CE-123

updated

CE-123 is a research code for a thiazole analogue of modafinil, sold for working memory, executive function, focus and motivation without the full stimulant profile. Its published work is rat and mouse studies and cell assays spanning about ten years, and no controlled human study exists: a PubMed query on 10 October 2026 found no record of CE-123 given to a person. Cognitive flexibility, effort-based choice and aged-rat motivation have rat support, working memory is not shown for CE-123 itself, and no study found a focus effect.

Selective dopamine transporter inhibitor (thiazole analogue of modafinil)

  • CE-123 is 5-(benzhydrylsulfinylmethyl)-1,3-thiazole, PubChem CID 118871455, C17H15NOS2, molecular weight 313.4; the (S)-enantiomer used in most papers is a separate record, CID 139577498.
  • In cells expressing human transporters CE-123 blocked dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters.
  • In healthy male rats, CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts in a set-shifting task, and visuospatial attention did not differ from control.
  • In rats the highest dose of (S)-CE-123 tested, 24.0 mg/kg, partially but significantly reversed a tetrabenazine-induced shift toward low-effort choice.
  • A PubMed query on 10 October 2026 returned 26 records, none reports CE-123 given to a person, and every one of the 16 papers with CE-123 results read lists Lubec G as an author.
  • A 2025 study in female Wistar rats found CE-123 increased bone length and growth plate size in healthy rats, and the authors call for safety studies, particularly in younger populations.

What is CE-123, and what is its regulatory status?

CE-123 is a research code for a thiazole analogue of modafinil, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole, studied mostly as the (S)-enantiomer. No label, application or registered study exists, and the neighboring codes CE-103, CE-104, CE-125 and CE-158 are different molecules.

CE-123 is 5-(benzhydrylsulfinylmethyl)-1,3-thiazole, PubChem CID 118871455 (no stereochemistry in the name), C17H15NOS2, 313.4 g/mol. CAS 1879038-73-9 and 2378384-49-5 are both among the synonyms, and which belongs to which form is not stated in the records reviewed. The sulfoxide is a stereocenter, and the (S)-enantiomer has its own record, CID 139577498.

The papers use the S-enantiomer in most work, written (S)-CE-123 or S-CE-123, and the racemate, written rac-CE-123, in at least one mouse study that compares the two, so a vial labeled CE-123 cannot be tied to either form by the name alone. Neighboring codes belong to different molecules: CE-103, CE-104, CE-125 and CE-158 are separate analogues, and the radial arm maze working-memory studies in this literature used CE-103, CE-104 and CE-125, not CE-123. No public record ties any vendor material to the studied compound.

On 10 October 2026 DailyMed returned no label for CE-123, an openFDA Drugs@FDA query returned no match, and ClinicalTrials.gov queries for CE-123, for (S)-CE-123 or S-CE-123, and for the chemical name returned no studies. Status outside the United States is not covered here.

PubChem: CE-123 racemate and (S)-enantiomer identity

Chemical identity record

PubChem, National Library of Medicine. Compound summary for CID 139577498, (S)-CE-123; the record without stereochemistry is CID 118871455, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole.

CE-123 is a research code for a thiazole analogue of modafinil, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole. PubChem CID 118871455 (no stereochemistry in the name), C17H15NOS2, 313.4 g/mol, with CAS 1879038-73-9 and 2378384-49-5 both among the synonyms. The sulfoxide is a stereocenter, and the (S)-enantiomer has its own record, CID 139577498 (listed as (S)-CE-123 and CE-123 S-isomer). The papers use the S-enantiomer in most work, written (S)-CE-123 or S-CE-123, and the racemate, written rac-CE-123, in at least one mouse study that compares the two. CE-103, CE-104, CE-125 and CE-158 are separate analogues.

Participants / model
Chemical identity, not a clinical population
Treatment
Defined molecule; racemate and S-enantiomer
Follow-up
Not applicable
Study design
Chemical database record
Funding
not stated in the source

Identity record only. A vial labeled CE-123 cannot be tied to either form by the name alone, which CAS number belongs to which form is not stated, and no public record ties any vendor material to the studied compound.

Read the original source
Label and registry searches, 10 October 2026: no label, no match, no study

Regulatory record

U.S. Food and Drug Administration (DailyMed label search; openFDA Drugs@FDA query) and ClinicalTrials.gov. Searches for CE-123, (S)-CE-123, S-CE-123 and the chemical name, run 10 October 2026.

DailyMed returned no label for CE-123, the openFDA Drugs@FDA query returned no match, and ClinicalTrials.gov queries for CE-123, for (S)-CE-123 or S-CE-123, and for the chemical name returned no studies.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated label, application and registry search
Funding
not stated in the source

An absence finding as of 10 October 2026. It covers United States label, application and registry records only.

Read the original source

What did the rat and mouse studies find?

In healthy male rats CE-123 improved cognitive flexibility in a set-shifting task, partially reversed a drug-induced loss of effort in a choice task and improved spatial memory in a hole-board task, and (S)-CE-123 improved motivation in aged rats. No attention effect was found, and working memory is not shown for CE-123. All of it is rat and mouse work, and no controlled human study exists.

In an attentional set-shifting task in healthy male rats, CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts than controls, which the authors read as increased cognitive flexibility. In a 5-choice serial reaction time task, R-modafinil at 10 mg/kg increased premature responses, an impulsivity measure, at the 10-second intertrial interval, and CE-123 at the same dose did not. Visuospatial attention did not differ between either drug and its control, apart from premature responses. The route is not in the abstract. This supports flexibility in rats and does not support a focus or attention effect.

In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task, with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. S-CE-123 improved performance of aged but not young rats in a reward-motivated spatial hole-board task. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently.

The radial arm maze working-memory reports in this literature are for the siblings CE-103 (dopamine uptake IC50 14.73 micromolar), CE-104 (27.88 micromolar) and CE-125 (4.1 micromolar), studied in male rats at 1 to 10 mg/kg, and they cannot be cited for CE-123. A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper whose abstract reports declarative, spatial and aversive memory rather than working memory.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123, 24.0 mg/kg from a tested range of 6.0 to 24.0, partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core and had no effect on fixed ratio responding alone; the route is not in the abstract. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, the authors report that subchronic S-CE-123 markedly enhanced motivation, giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity. 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups, and the authors say the profile resembles that of modafinil in the clinic.

Healthy male rats: fewer extra-dimensional shifts at 0.3 and 1.0 mg/kg, no attention effect

Animal study

Nikiforuk A et al. Front Behav Neurosci. 2017;11:222. PMID 29230168.

In an attentional set-shifting task, rats treated with CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts than controls, which the authors read as increased cognitive flexibility. In a 5-choice serial reaction time task, R-modafinil at 10 mg/kg increased premature responses (an impulsivity measure) at the 10-second intertrial interval, and CE-123 at the same dose did not. Visuospatial attention did not differ between either drug and its control, apart from premature responses.

Participants / model
Healthy male rats
Treatment
CE-123 at 0.1, 0.3 and 1.0 mg/kg (and 10 mg/kg in the 5-choice task); route not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study
Funding
not stated in the source

Supports cognitive flexibility in rats and does not support a focus or attention effect.

Read the original source
Dopamine transporter IC50 4.606 micromolar; hole-board memory in rats; aged-rat and mouse memory

Animal study

Kristofova M et al. Behav Brain Res. 2018;343:83-94. PMID 29410048.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task (reference memory indices and latency), with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. A 2023 paper from the same research network (PMID 36979402) calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats, and reports it improved performance of aged but not young rats in a reward-motivated spatial hole-board task. A 2020 structure-activity paper on the thiazole modafinil analogues (PMID 31841637) reports the S configuration generally gave the highest DAT activity and selectivity. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently (PMID 31031603).

Participants / model
Cells expressing human transporters; male Sprague-Dawley rats; aged and young rats; mice
Treatment
CE-123 in cell uptake assays; daily single dose in rats; doses and routes mostly not stated in the abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The radial arm maze working-memory reports in this literature are for the siblings CE-103, CE-104 and CE-125 and cannot be cited for CE-123. CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Read the original source
Effort-based choice in rats; motivation in 27 aged rats

Animal study

Rotolo RA et al. Front Pharmacol. 2019;10:682. PMID 31316379.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123 (24.0 mg/kg, from a tested range of 6.0 to 24.0) partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core, and had no effect on fixed ratio responding alone. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, subchronic S-CE-123 markedly enhanced motivation according to the authors (PMID 34907284), giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity; 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups. The authors say the profile resembles that of modafinil in the clinic.

Participants / model
Male rats, including 27 aged rats
Treatment
(S)-CE-123 6.0 to 24.0 mg/kg; subchronic dosing in the aged-rat study, dose and route not stated in that abstract; route not stated in the effort-choice abstract
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The best-supported part of the supplier claim, and still rat data. The aged-rat abstract reports a mild rise in impulsivity.

Read the original source
PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

Read the original source

How does CE-123 act on dopamine signaling?

CE-123 is a low-affinity but selective dopamine transporter inhibitor: in cells expressing human transporters it blocked dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. It is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. A 2023 paper from the same research network calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, and reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats; the abstract gives no doses. A 2020 structure-activity paper on the thiazole modafinil analogues, a series that includes CE-123, reports the S configuration generally gave the highest DAT activity and selectivity.

In rats, S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil. In anesthetized rats (S)-CE-123 reduced firing of pyramidal neurons in infralimbic and prelimbic cortex and neither it nor R-modafinil changed ventral tegmental area dopamine cell firing, and in freely moving rats it raised dopamine in that cortex. In one rat study daily CE-123 raised D1 receptor protein in hippocampal CA1 and CA3 and the total DAT level.

CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Dopamine transporter IC50 4.606 micromolar; hole-board memory in rats; aged-rat and mouse memory

Animal study

Kristofova M et al. Behav Brain Res. 2018;343:83-94. PMID 29410048.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task (reference memory indices and latency), with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. A 2023 paper from the same research network (PMID 36979402) calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats, and reports it improved performance of aged but not young rats in a reward-motivated spatial hole-board task. A 2020 structure-activity paper on the thiazole modafinil analogues (PMID 31841637) reports the S configuration generally gave the highest DAT activity and selectivity. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently (PMID 31031603).

Participants / model
Cells expressing human transporters; male Sprague-Dawley rats; aged and young rats; mice
Treatment
CE-123 in cell uptake assays; daily single dose in rats; doses and routes mostly not stated in the abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The radial arm maze working-memory reports in this literature are for the siblings CE-103, CE-104 and CE-125 and cannot be cited for CE-123. CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Read the original source
Acute rat measures: lower accumbens shell signal, no 50-kHz vocalizations

Animal study

Sagheddu C et al. Biomolecules. 2020;10(5). PMID 32443397.

In anesthetized rats (S)-CE-123 given intravenously at 1.25 to 10 mg/kg dose-dependently reduced firing of pyramidal neurons in infralimbic and prelimbic cortex and R-modafinil did not, and neither drug changed ventral tegmental area dopamine cell firing. In freely moving rats (S)-CE-123 at 10 mg/kg intraperitoneally raised dopamine in that cortex, and in the nucleus accumbens shell produced a low and transitory increase seen only after (S)-CE-123. Neither compound triggered 50-kHz ultrasonic vocalizations, a marker of positive affect and drug reward.

Participants / model
Adult male rats
Treatment
Intravenous (S)-CE-123 1.25 to 10 mg/kg; intraperitoneal 10 mg/kg
Follow-up
Acute measures
Study design
Original preclinical study
Funding
not stated in the source

Three small acute measures in rats. Nothing in the records reviewed tests abuse liability, self-administration or cardiovascular effects, and no comparison with a classic stimulant such as methylphenidate or amphetamine appears in the abstracts read.

Read the original source
Bone growth signal in healthy rats; brain penetration and metabolism of S-CE-123

Animal study

Osiak-Wicha C et al. J Clin Med. 2025;14(7). PMID 40217875.

A 2025 study in female Wistar rats found CE-123 in healthy rats increased bone length and growth plate size, and the authors say this raises questions about long-term impact on skeletal development and call for safety studies, particularly in younger populations. Separately, S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil, and 9.3-fold faster hepatic metabolism than R-modafinil (PMID 38069277; the abstract does not give the metabolic species or the half-life). A 2023 paper reports a basic neurotoxic screen and a GPCR and kinome screen without giving results in the abstract (PMID 36979402). A 2024 paper reports a 1 kg preclinical batch made at purity above 99% and enantiomeric excess of 95% (PMID 38524446), which shows development effort and says nothing about toxicology.

Participants / model
Female Wistar rats; rats; liver preparations (species not stated)
Treatment
CE-123; dose and route not stated in the bone and pharmacokinetic abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The abstract gives no dose, route or size for the bone finding, so none is stated here. No LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found among the abstracts read.

Read the original source

What did the developing-rat disease models show?

In developing rats with an induced deficit (neonatal alcohol exposure, maternal separation, valproate exposure or stress), CE-123 reduced hyperactivity and improved learning, social behavior or fear extinction. These are disease-model results in young animals and are not evidence for healthy cognition.

In rats exposed to alcohol as neonates, CE-123 at 3 and 10 mg/kg inhibited hyperactivity and at 10 mg/kg ameliorated reversal learning impairment. In maternally separated adolescent rats CE-123 ameliorated spatial learning and memory deficits, more in females. Chronic CE-123 prevented social recognition deficits after neonatal ethanol exposure. In a valproate rat model of autism, 10 mg/kg intraperitoneally from postnatal day 10 to 23 attenuated several behavioral abnormalities without non-specific locomotor stimulation. In stressed adolescent male rats, 10 mg/kg intraperitoneally reduced freezing during fear extinction.

All of this is in developing rats with an induced deficit, given CE-123 by intraperitoneal injection at 1 to 10 mg/kg. None of it tests healthy cognition, and none is in people.

Developing-rat disease models: alcohol exposure, maternal separation, valproate, stress

Animal study

Gibula-Tarlowska E et al. Behav Brain Res. 2021;410:113326. PMID 33940050.

In rats exposed to alcohol as neonates, CE-123 at 3 and 10 mg/kg inhibited hyperactivity and at 10 mg/kg ameliorated reversal learning impairment. In maternally separated adolescent rats CE-123 ameliorated spatial learning and memory deficits, more in females (PMID 36142621). Chronic CE-123 prevented social recognition deficits after neonatal ethanol exposure (PMID 38256113). In a valproate rat model of autism, 10 mg/kg intraperitoneally from postnatal day 10 to 23 attenuated several behavioral abnormalities without non-specific locomotor stimulation (PMID 42501761). In stressed adolescent male rats, 10 mg/kg intraperitoneally reduced freezing during fear extinction (PMID 42794782).

Participants / model
Neonatal ethanol, maternally separated, valproate-exposed and fear-conditioned rats
Treatment
Intraperitoneal injection of CE-123, 1 to 10 mg/kg
Follow-up
Postnatal day 10 to 23 in the valproate model; not stated for the others
Study design
Original preclinical studies
Funding
not stated in the source

All of this is in developing rats with an induced deficit, so it is not evidence for healthy cognition.

Read the original source

Has CE-123 been tested in people?

No. A PubMed query on 10 October 2026 returned 26 records, and none reports CE-123 given to a person. ClinicalTrials.gov returned no studies.

A PubMed query on 10 October 2026 for CE-123, CE123, benzhydrylsulfinyl and benzhydrylsulfinylmethyl returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10. They were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person.

Of the 16 papers with CE-123 results that were read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories, including teams in Connecticut, Cagliari, Lublin and Budapest. ClinicalTrials.gov queries for CE-123, for (S)-CE-123 or S-CE-123 and for the chemical name returned no studies. No controlled human trial exists in the records reviewed.

PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

Read the original source
Label and registry searches, 10 October 2026: no label, no match, no study

Regulatory record

U.S. Food and Drug Administration (DailyMed label search; openFDA Drugs@FDA query) and ClinicalTrials.gov. Searches for CE-123, (S)-CE-123, S-CE-123 and the chemical name, run 10 October 2026.

DailyMed returned no label for CE-123, the openFDA Drugs@FDA query returned no match, and ClinicalTrials.gov queries for CE-123, for (S)-CE-123 or S-CE-123, and for the chemical name returned no studies.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated label, application and registry search
Funding
not stated in the source

An absence finding as of 10 October 2026. It covers United States label, application and registry records only.

Read the original source

Does CE-123 improve memory, focus and motivation?

Partly, and only in rats and mice. Motivation and cognitive flexibility are supported in rats, and memory as spatial reference and social memory in rats and mice, but working memory is not shown for CE-123 and two rat studies found no attention effect. The without-the-full-stimulant-profile wording rests on a few acute rat measures.

Sellers claim working memory, executive function, focus and motivation without the full stimulant profile. Motivation is the best-supported part, with effort-based choice and progressive ratio results in rats and better motivation in aged rats. Executive function is supported as cognitive flexibility in a set-shifting task in healthy rats.

Memory is supported as spatial reference memory in rats and as social recognition memory in mice. Working memory is not shown for CE-123, because the working-memory studies in this literature used CE-103, CE-104 and CE-125. Focus is not supported, because two rat studies found no attention effect.

The without-the-full-stimulant-profile wording rests on three small acute rat measures. In anesthetized rats (S)-CE-123 given intravenously at 1.25 to 10 mg/kg dose-dependently reduced firing of pyramidal neurons in infralimbic and prelimbic cortex and R-modafinil did not, and neither drug changed ventral tegmental area dopamine cell firing. In freely moving rats (S)-CE-123 at 10 mg/kg intraperitoneally raised dopamine in that cortex, and in the nucleus accumbens shell produced a low and transitory increase seen only after (S)-CE-123. Neither compound triggered 50-kHz ultrasonic vocalizations, a marker of positive affect and drug reward. Impulsivity results differ: no rise in premature responses at 10 mg/kg in healthy rats and a mild rise in aged rats. Nothing in the records reviewed tests abuse liability, self-administration or cardiovascular effects, and no comparison with a classic stimulant such as methylphenidate or amphetamine appears in the abstracts read.

Effort-based choice in rats; motivation in 27 aged rats

Animal study

Rotolo RA et al. Front Pharmacol. 2019;10:682. PMID 31316379.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123 (24.0 mg/kg, from a tested range of 6.0 to 24.0) partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core, and had no effect on fixed ratio responding alone. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, subchronic S-CE-123 markedly enhanced motivation according to the authors (PMID 34907284), giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity; 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups. The authors say the profile resembles that of modafinil in the clinic.

Participants / model
Male rats, including 27 aged rats
Treatment
(S)-CE-123 6.0 to 24.0 mg/kg; subchronic dosing in the aged-rat study, dose and route not stated in that abstract; route not stated in the effort-choice abstract
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The best-supported part of the supplier claim, and still rat data. The aged-rat abstract reports a mild rise in impulsivity.

Read the original source
Healthy male rats: fewer extra-dimensional shifts at 0.3 and 1.0 mg/kg, no attention effect

Animal study

Nikiforuk A et al. Front Behav Neurosci. 2017;11:222. PMID 29230168.

In an attentional set-shifting task, rats treated with CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts than controls, which the authors read as increased cognitive flexibility. In a 5-choice serial reaction time task, R-modafinil at 10 mg/kg increased premature responses (an impulsivity measure) at the 10-second intertrial interval, and CE-123 at the same dose did not. Visuospatial attention did not differ between either drug and its control, apart from premature responses.

Participants / model
Healthy male rats
Treatment
CE-123 at 0.1, 0.3 and 1.0 mg/kg (and 10 mg/kg in the 5-choice task); route not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study
Funding
not stated in the source

Supports cognitive flexibility in rats and does not support a focus or attention effect.

Read the original source
Dopamine transporter IC50 4.606 micromolar; hole-board memory in rats; aged-rat and mouse memory

Animal study

Kristofova M et al. Behav Brain Res. 2018;343:83-94. PMID 29410048.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task (reference memory indices and latency), with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. A 2023 paper from the same research network (PMID 36979402) calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats, and reports it improved performance of aged but not young rats in a reward-motivated spatial hole-board task. A 2020 structure-activity paper on the thiazole modafinil analogues (PMID 31841637) reports the S configuration generally gave the highest DAT activity and selectivity. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently (PMID 31031603).

Participants / model
Cells expressing human transporters; male Sprague-Dawley rats; aged and young rats; mice
Treatment
CE-123 in cell uptake assays; daily single dose in rats; doses and routes mostly not stated in the abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The radial arm maze working-memory reports in this literature are for the siblings CE-103, CE-104 and CE-125 and cannot be cited for CE-123. CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Read the original source
Acute rat measures: lower accumbens shell signal, no 50-kHz vocalizations

Animal study

Sagheddu C et al. Biomolecules. 2020;10(5). PMID 32443397.

In anesthetized rats (S)-CE-123 given intravenously at 1.25 to 10 mg/kg dose-dependently reduced firing of pyramidal neurons in infralimbic and prelimbic cortex and R-modafinil did not, and neither drug changed ventral tegmental area dopamine cell firing. In freely moving rats (S)-CE-123 at 10 mg/kg intraperitoneally raised dopamine in that cortex, and in the nucleus accumbens shell produced a low and transitory increase seen only after (S)-CE-123. Neither compound triggered 50-kHz ultrasonic vocalizations, a marker of positive affect and drug reward.

Participants / model
Adult male rats
Treatment
Intravenous (S)-CE-123 1.25 to 10 mg/kg; intraperitoneal 10 mg/kg
Follow-up
Acute measures
Study design
Original preclinical study
Funding
not stated in the source

Three small acute measures in rats. Nothing in the records reviewed tests abuse liability, self-administration or cardiovascular effects, and no comparison with a classic stimulant such as methylphenidate or amphetamine appears in the abstracts read.

Read the original source
PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

Read the original source

What is known about the safety of CE-123?

No human safety, pharmacokinetic or toxicology data exist for CE-123. A 2025 rat study found CE-123 increased bone length and growth plate size in healthy rats, and its authors call for safety studies, particularly in younger populations; no LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found.

No record reports CE-123 given to a person, so no human adverse event, tolerability or interaction information exists.

A 2025 study in female Wistar rats found CE-123 in healthy rats increased bone length and growth plate size, and the authors say this raises questions about long-term impact on skeletal development and call for safety studies, particularly in younger populations. The abstract gives no dose, route or size, so none is stated here.

S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil, and 9.3-fold faster hepatic metabolism than R-modafinil; the abstract does not give the species of the liver preparation or the half-life. A 2023 paper reports a basic neurotoxic screen and a GPCR and kinome screen without giving results in the abstract. A 2024 paper reports a 1 kg preclinical batch made at purity above 99% and enantiomeric excess of 95%, which shows development effort and says nothing about toxicology.

In aged rats subchronic S-CE-123 mildly increased impulsivity. No LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found among the abstracts read. Product identity is a separate concern, because a vial labeled CE-123 cannot be tied to the S-enantiomer or the racemate by the name alone.

Bone growth signal in healthy rats; brain penetration and metabolism of S-CE-123

Animal study

Osiak-Wicha C et al. J Clin Med. 2025;14(7). PMID 40217875.

A 2025 study in female Wistar rats found CE-123 in healthy rats increased bone length and growth plate size, and the authors say this raises questions about long-term impact on skeletal development and call for safety studies, particularly in younger populations. Separately, S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil, and 9.3-fold faster hepatic metabolism than R-modafinil (PMID 38069277; the abstract does not give the metabolic species or the half-life). A 2023 paper reports a basic neurotoxic screen and a GPCR and kinome screen without giving results in the abstract (PMID 36979402). A 2024 paper reports a 1 kg preclinical batch made at purity above 99% and enantiomeric excess of 95% (PMID 38524446), which shows development effort and says nothing about toxicology.

Participants / model
Female Wistar rats; rats; liver preparations (species not stated)
Treatment
CE-123; dose and route not stated in the bone and pharmacokinetic abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The abstract gives no dose, route or size for the bone finding, so none is stated here. No LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found among the abstracts read.

Read the original source
Effort-based choice in rats; motivation in 27 aged rats

Animal study

Rotolo RA et al. Front Pharmacol. 2019;10:682. PMID 31316379.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123 (24.0 mg/kg, from a tested range of 6.0 to 24.0) partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core, and had no effect on fixed ratio responding alone. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, subchronic S-CE-123 markedly enhanced motivation according to the authors (PMID 34907284), giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity; 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups. The authors say the profile resembles that of modafinil in the clinic.

Participants / model
Male rats, including 27 aged rats
Treatment
(S)-CE-123 6.0 to 24.0 mg/kg; subchronic dosing in the aged-rat study, dose and route not stated in that abstract; route not stated in the effort-choice abstract
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The best-supported part of the supplier claim, and still rat data. The aged-rat abstract reports a mild rise in impulsivity.

Read the original source
PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

Read the original source
PubChem: CE-123 racemate and (S)-enantiomer identity

Chemical identity record

PubChem, National Library of Medicine. Compound summary for CID 139577498, (S)-CE-123; the record without stereochemistry is CID 118871455, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole.

CE-123 is a research code for a thiazole analogue of modafinil, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole. PubChem CID 118871455 (no stereochemistry in the name), C17H15NOS2, 313.4 g/mol, with CAS 1879038-73-9 and 2378384-49-5 both among the synonyms. The sulfoxide is a stereocenter, and the (S)-enantiomer has its own record, CID 139577498 (listed as (S)-CE-123 and CE-123 S-isomer). The papers use the S-enantiomer in most work, written (S)-CE-123 or S-CE-123, and the racemate, written rac-CE-123, in at least one mouse study that compares the two. CE-103, CE-104, CE-125 and CE-158 are separate analogues.

Participants / model
Chemical identity, not a clinical population
Treatment
Defined molecule; racemate and S-enantiomer
Follow-up
Not applicable
Study design
Chemical database record
Funding
not stated in the source

Identity record only. A vial labeled CE-123 cannot be tied to either form by the name alone, which CAS number belongs to which form is not stated, and no public record ties any vendor material to the studied compound.

Read the original source

Why does CE-123 sit in C tier?

CE-123 has a plausible, well-characterized mechanism and about ten years of consistent rat work, with no failed trial or documented human harm, but the data are rats and mice only, with no human exposure, no toxicology, an author link on every CE-123 paper read and a bone growth signal that needs follow-up.

The mechanism is plausible and well characterized: a selective, low-affinity dopamine transporter blocker with better brain penetration than R-modafinil in rats. The animal work spans about ten years and several laboratories, and the effects on set shifting, effort-based choice and aged-rat motivation are internally consistent. Nothing in the records reviewed shows a failed trial or documented human harm.

The data are thin in the C sense: rats and mice only, no human exposure, no human pharmacokinetics, no toxicology, an author link (Lubec G) on every CE-123 paper read, a healthy-rat bone growth signal that needs follow-up, and no registered study.

Dopamine transporter IC50 4.606 micromolar; hole-board memory in rats; aged-rat and mouse memory

Animal study

Kristofova M et al. Behav Brain Res. 2018;343:83-94. PMID 29410048.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task (reference memory indices and latency), with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. A 2023 paper from the same research network (PMID 36979402) calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats, and reports it improved performance of aged but not young rats in a reward-motivated spatial hole-board task. A 2020 structure-activity paper on the thiazole modafinil analogues (PMID 31841637) reports the S configuration generally gave the highest DAT activity and selectivity. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently (PMID 31031603).

Participants / model
Cells expressing human transporters; male Sprague-Dawley rats; aged and young rats; mice
Treatment
CE-123 in cell uptake assays; daily single dose in rats; doses and routes mostly not stated in the abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The radial arm maze working-memory reports in this literature are for the siblings CE-103, CE-104 and CE-125 and cannot be cited for CE-123. CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Read the original source
Effort-based choice in rats; motivation in 27 aged rats

Animal study

Rotolo RA et al. Front Pharmacol. 2019;10:682. PMID 31316379.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123 (24.0 mg/kg, from a tested range of 6.0 to 24.0) partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core, and had no effect on fixed ratio responding alone. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, subchronic S-CE-123 markedly enhanced motivation according to the authors (PMID 34907284), giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity; 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups. The authors say the profile resembles that of modafinil in the clinic.

Participants / model
Male rats, including 27 aged rats
Treatment
(S)-CE-123 6.0 to 24.0 mg/kg; subchronic dosing in the aged-rat study, dose and route not stated in that abstract; route not stated in the effort-choice abstract
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The best-supported part of the supplier claim, and still rat data. The aged-rat abstract reports a mild rise in impulsivity.

Read the original source
Healthy male rats: fewer extra-dimensional shifts at 0.3 and 1.0 mg/kg, no attention effect

Animal study

Nikiforuk A et al. Front Behav Neurosci. 2017;11:222. PMID 29230168.

In an attentional set-shifting task, rats treated with CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts than controls, which the authors read as increased cognitive flexibility. In a 5-choice serial reaction time task, R-modafinil at 10 mg/kg increased premature responses (an impulsivity measure) at the 10-second intertrial interval, and CE-123 at the same dose did not. Visuospatial attention did not differ between either drug and its control, apart from premature responses.

Participants / model
Healthy male rats
Treatment
CE-123 at 0.1, 0.3 and 1.0 mg/kg (and 10 mg/kg in the 5-choice task); route not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study
Funding
not stated in the source

Supports cognitive flexibility in rats and does not support a focus or attention effect.

Read the original source
PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

Read the original source
Bone growth signal in healthy rats; brain penetration and metabolism of S-CE-123

Animal study

Osiak-Wicha C et al. J Clin Med. 2025;14(7). PMID 40217875.

A 2025 study in female Wistar rats found CE-123 in healthy rats increased bone length and growth plate size, and the authors say this raises questions about long-term impact on skeletal development and call for safety studies, particularly in younger populations. Separately, S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil, and 9.3-fold faster hepatic metabolism than R-modafinil (PMID 38069277; the abstract does not give the metabolic species or the half-life). A 2023 paper reports a basic neurotoxic screen and a GPCR and kinome screen without giving results in the abstract (PMID 36979402). A 2024 paper reports a 1 kg preclinical batch made at purity above 99% and enantiomeric excess of 95% (PMID 38524446), which shows development effort and says nothing about toxicology.

Participants / model
Female Wistar rats; rats; liver preparations (species not stated)
Treatment
CE-123; dose and route not stated in the bone and pharmacokinetic abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The abstract gives no dose, route or size for the bone finding, so none is stated here. No LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found among the abstracts read.

Read the original source

Studies and sources

PubChem: CE-123 racemate and (S)-enantiomer identity

Chemical identity record

PubChem, National Library of Medicine. Compound summary for CID 139577498, (S)-CE-123; the record without stereochemistry is CID 118871455, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole.

CE-123 is a research code for a thiazole analogue of modafinil, 5-(benzhydrylsulfinylmethyl)-1,3-thiazole. PubChem CID 118871455 (no stereochemistry in the name), C17H15NOS2, 313.4 g/mol, with CAS 1879038-73-9 and 2378384-49-5 both among the synonyms. The sulfoxide is a stereocenter, and the (S)-enantiomer has its own record, CID 139577498 (listed as (S)-CE-123 and CE-123 S-isomer). The papers use the S-enantiomer in most work, written (S)-CE-123 or S-CE-123, and the racemate, written rac-CE-123, in at least one mouse study that compares the two. CE-103, CE-104, CE-125 and CE-158 are separate analogues.

Participants / model
Chemical identity, not a clinical population
Treatment
Defined molecule; racemate and S-enantiomer
Follow-up
Not applicable
Study design
Chemical database record
Funding
not stated in the source

Identity record only. A vial labeled CE-123 cannot be tied to either form by the name alone, which CAS number belongs to which form is not stated, and no public record ties any vendor material to the studied compound.

Read the original source
Dopamine transporter IC50 4.606 micromolar; hole-board memory in rats; aged-rat and mouse memory

Animal study

Kristofova M et al. Behav Brain Res. 2018;343:83-94. PMID 29410048.

In cells expressing human transporters, CE-123 blocked [3H]dopamine uptake with an IC50 of 4.606 micromolar, with negligible effects on the serotonin and norepinephrine transporters. In male Sprague-Dawley rats a daily single dose of CE-123 enhanced memory acquisition and retrieval in a spatial hole-board task (reference memory indices and latency), with increased D1 receptor protein in hippocampal CA1 and CA3 and a raised total DAT level; dose and route are not in the abstract. A 2023 paper from the same research network (PMID 36979402) calls S-CE-123 a low-affinity but highly selective dopamine reuptake inhibitor with good bioavailability, reports it did not induce hyperlocomotion or anxiogenic or stereotypic behavior in young rats, and reports it improved performance of aged but not young rats in a reward-motivated spatial hole-board task. A 2020 structure-activity paper on the thiazole modafinil analogues (PMID 31841637) reports the S configuration generally gave the highest DAT activity and selectivity. In mice, rac-CE-123 blocked retroactive interference with long-term social recognition memory induced at 3 hours but not 6 hours after learning, S-CE-123 blocked it at 6 hours but not 3 hours and did not block proactive interference, and both raised nucleus accumbens dopamine release dose-dependently (PMID 31031603).

Participants / model
Cells expressing human transporters; male Sprague-Dawley rats; aged and young rats; mice
Treatment
CE-123 in cell uptake assays; daily single dose in rats; doses and routes mostly not stated in the abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The radial arm maze working-memory reports in this literature are for the siblings CE-103, CE-104 and CE-125 and cannot be cited for CE-123. CE-123 is still a dopamine transporter inhibitor, the same mechanism class as the stimulants the supplier claim is set against.

Read the original source
Healthy male rats: fewer extra-dimensional shifts at 0.3 and 1.0 mg/kg, no attention effect

Animal study

Nikiforuk A et al. Front Behav Neurosci. 2017;11:222. PMID 29230168.

In an attentional set-shifting task, rats treated with CE-123 at 0.3 and 1.0 mg/kg but not 0.1 mg/kg made fewer extra-dimensional shifts than controls, which the authors read as increased cognitive flexibility. In a 5-choice serial reaction time task, R-modafinil at 10 mg/kg increased premature responses (an impulsivity measure) at the 10-second intertrial interval, and CE-123 at the same dose did not. Visuospatial attention did not differ between either drug and its control, apart from premature responses.

Participants / model
Healthy male rats
Treatment
CE-123 at 0.1, 0.3 and 1.0 mg/kg (and 10 mg/kg in the 5-choice task); route not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study
Funding
not stated in the source

Supports cognitive flexibility in rats and does not support a focus or attention effect.

Read the original source
Effort-based choice in rats; motivation in 27 aged rats

Animal study

Rotolo RA et al. Front Pharmacol. 2019;10:682. PMID 31316379.

In a fixed ratio 5 versus chow choice test, tetrabenazine at 1.0 mg/kg shifted choice toward low effort, and the highest co-administered dose of (S)-CE-123 (24.0 mg/kg, from a tested range of 6.0 to 24.0) partially but significantly reversed that. The same dose raised lever pressing on a progressive ratio choice task, raised extracellular dopamine in the nucleus accumbens core, and had no effect on fixed ratio responding alone. In 27 male Lister Hooded rats aged 26 months that had learned several tasks, subchronic S-CE-123 markedly enhanced motivation according to the authors (PMID 34907284), giving superior performance in a new-to-learn operant discrimination task and a social cooperation assay, did not affect attention or spatial and motor learning, and mildly increased impulsivity; 182 protein groups in prefrontal cortex synaptosomes differed between treatment groups. The authors say the profile resembles that of modafinil in the clinic.

Participants / model
Male rats, including 27 aged rats
Treatment
(S)-CE-123 6.0 to 24.0 mg/kg; subchronic dosing in the aged-rat study, dose and route not stated in that abstract; route not stated in the effort-choice abstract
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The best-supported part of the supplier claim, and still rat data. The aged-rat abstract reports a mild rise in impulsivity.

Read the original source
Acute rat measures: lower accumbens shell signal, no 50-kHz vocalizations

Animal study

Sagheddu C et al. Biomolecules. 2020;10(5). PMID 32443397.

In anesthetized rats (S)-CE-123 given intravenously at 1.25 to 10 mg/kg dose-dependently reduced firing of pyramidal neurons in infralimbic and prelimbic cortex and R-modafinil did not, and neither drug changed ventral tegmental area dopamine cell firing. In freely moving rats (S)-CE-123 at 10 mg/kg intraperitoneally raised dopamine in that cortex, and in the nucleus accumbens shell produced a low and transitory increase seen only after (S)-CE-123. Neither compound triggered 50-kHz ultrasonic vocalizations, a marker of positive affect and drug reward.

Participants / model
Adult male rats
Treatment
Intravenous (S)-CE-123 1.25 to 10 mg/kg; intraperitoneal 10 mg/kg
Follow-up
Acute measures
Study design
Original preclinical study
Funding
not stated in the source

Three small acute measures in rats. Nothing in the records reviewed tests abuse liability, self-administration or cardiovascular effects, and no comparison with a classic stimulant such as methylphenidate or amphetamine appears in the abstracts read.

Read the original source
Developing-rat disease models: alcohol exposure, maternal separation, valproate, stress

Animal study

Gibula-Tarlowska E et al. Behav Brain Res. 2021;410:113326. PMID 33940050.

In rats exposed to alcohol as neonates, CE-123 at 3 and 10 mg/kg inhibited hyperactivity and at 10 mg/kg ameliorated reversal learning impairment. In maternally separated adolescent rats CE-123 ameliorated spatial learning and memory deficits, more in females (PMID 36142621). Chronic CE-123 prevented social recognition deficits after neonatal ethanol exposure (PMID 38256113). In a valproate rat model of autism, 10 mg/kg intraperitoneally from postnatal day 10 to 23 attenuated several behavioral abnormalities without non-specific locomotor stimulation (PMID 42501761). In stressed adolescent male rats, 10 mg/kg intraperitoneally reduced freezing during fear extinction (PMID 42794782).

Participants / model
Neonatal ethanol, maternally separated, valproate-exposed and fear-conditioned rats
Treatment
Intraperitoneal injection of CE-123, 1 to 10 mg/kg
Follow-up
Postnatal day 10 to 23 in the valproate model; not stated for the others
Study design
Original preclinical studies
Funding
not stated in the source

All of this is in developing rats with an induced deficit, so it is not evidence for healthy cognition.

Read the original source
Bone growth signal in healthy rats; brain penetration and metabolism of S-CE-123

Animal study

Osiak-Wicha C et al. J Clin Med. 2025;14(7). PMID 40217875.

A 2025 study in female Wistar rats found CE-123 in healthy rats increased bone length and growth plate size, and the authors say this raises questions about long-term impact on skeletal development and call for safety studies, particularly in younger populations. Separately, S-CE-123 had an unbound brain-to-plasma ratio (Kp,uu,brain) of 0.5 versus 0.1 for R-modafinil, and 9.3-fold faster hepatic metabolism than R-modafinil (PMID 38069277; the abstract does not give the metabolic species or the half-life). A 2023 paper reports a basic neurotoxic screen and a GPCR and kinome screen without giving results in the abstract (PMID 36979402). A 2024 paper reports a 1 kg preclinical batch made at purity above 99% and enantiomeric excess of 95% (PMID 38524446), which shows development effort and says nothing about toxicology.

Participants / model
Female Wistar rats; rats; liver preparations (species not stated)
Treatment
CE-123; dose and route not stated in the bone and pharmacokinetic abstracts
Follow-up
not stated in the source
Study design
Original preclinical studies
Funding
not stated in the source

The abstract gives no dose, route or size for the bone finding, so none is stated here. No LD50, repeat-dose, genotoxicity, cardiovascular or abuse-liability study was found among the abstracts read.

Read the original source
PubMed, 10 October 2026: 26 records, none gives CE-123 to a person

PubMed search record

PubMed search run 10 October 2026: "CE-123"[tiab] OR CE123[tiab] OR "benzhydrylsulfinyl"[tiab] OR "benzhydrylsulfinylmethyl"[tiab], with a follow-up query adding human, humans, patients, volunteers, clinical, trial or trials.

The search returned 26 records. Adding human, humans, patients, volunteers, clinical, trial or trials returned 16, and abstracts were read for all 16 and for the other 10; they were rat and mouse studies, cell assays, three unrelated modafinil chemistry papers, a lactation database entry on armodafinil and a zebrafish modafinil paper, and none reports CE-123 given to a person. Of the 16 papers with CE-123 results read, every one lists Lubec G as an author, with a synthesis group (Kalaba P, Langer T) on most, though behavioral work came from several laboratories (Connecticut, Cagliari, Lublin and Budapest teams among them). A PubMed query for the CE-123 names with working memory, radial arm maze or delayed returned 1 record, a 2026 rat autism-model paper (PMID 42501761) whose abstract reports declarative, spatial and aversive memory rather than working memory. The 2025 Savchenko paper (PMID 39710336) lists CE-123 in its aims, but its abstract reports no CE-123 result and it was not used.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated literature search
Funding
not stated in the source

An absence finding as of 10 October 2026, not proof that no unpublished or unindexed work exists.

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Label and registry searches, 10 October 2026: no label, no match, no study

Regulatory record

U.S. Food and Drug Administration (DailyMed label search; openFDA Drugs@FDA query) and ClinicalTrials.gov. Searches for CE-123, (S)-CE-123, S-CE-123 and the chemical name, run 10 October 2026.

DailyMed returned no label for CE-123, the openFDA Drugs@FDA query returned no match, and ClinicalTrials.gov queries for CE-123, for (S)-CE-123 or S-CE-123, and for the chemical name returned no studies.

Participants / model
Records reviewed, not a population
Treatment
Not applicable
Follow-up
Searches run on 10 October 2026
Study design
Dated label, application and registry search
Funding
not stated in the source

An absence finding as of 10 October 2026. It covers United States label, application and registry records only.

Read the original source

Why is CE-123 in C tier?

C fits a research compound with a plausible, well-characterized dopamine transporter mechanism, about ten years of consistent rat work and no failed trial or documented human harm in the records reviewed. The data are thin: rats and mice only, no human exposure, no toxicology, an author link on every CE-123 paper read, a bone growth signal in healthy rats and no registered study.