fladrafinil
The only modern human study shows that fladrafinil converts to flmodafinil after one dose. It measured metabolism and detection, with no wakefulness, focus, or safety endpoint. An old patent claims human benefit without providing an appraisable trial record.
Small-molecule experimental adrafinil analog
- Six volunteers each received one analytically adjusted 20 mg exposure; no benefit or adverse-event endpoint was reported.
- The fladrafinil bottle assayed 93.1 mg/mL against a 100 mg/mL label. The near-twofold error belonged to the separate flmodafinil bottle.
- A patent reports stimulant-like rodent effects and an undocumented human hypersomnia claim with no denominator or outcome table.
- A urinary metabolite detected for two weeks is not a two-week half-life or effect.
What is fladrafinil?
Fladrafinil is CRL-40,941, the N-hydroxy bis-fluoro analog of adrafinil. It is chemically distinct from flmodafinil, CRL-40,940.
An FDA-linked analytical method can distinguish the compounds. Analytical identity does not show that a retail liquid contains the labeled strength or that the compound is clinically effective.
FDA analytical method for modafinil analogs
Primary analytical methods poster
US FDA. Development and Validation of an Analytical Method to Identify and Quantitate Novel Modafinil Analogs in Dietary Supplements. 2023.
The method distinguishes modafinil, adrafinil, CRL-40,940, CRL-40,941, and N-methyl-4,4-difluoromodafinil.
- Participants / model
- Chemical standards and supplement analysis
- Follow-up
- Method-development study
- Study design
- LC-HRMS analytical method
Identifying a molecule is not demonstrating an approved indication, efficacy, or safe dose.
Read the original sourceDevelopment and Validation of an Analytical Method to Identify and Quantitate Novel Modafinil Analogs in Products Marketed as Dietary Supplements.
Primary analytical study
Bakota EL et al. Journal of Dietary Supplements. 2025. PMID 39466147.
The method distinguishes modafinil, adrafinil, CRL-40,940 and CRL-40,941; four tested products were labeled as and contained adrafinil.
- Participants / model
- Four products labeled as adrafinil plus analytical standards
- Follow-up
- Cross-sectional product testing
- Study design
- Laboratory method validation and market-sample analysis
The study does not report that the products contained either fluorinated analog and supplies no efficacy or safety result.
Read the original sourcePubChem: fladrafinil chemical identity
Government chemical identity database
National Library of Medicine. PubChem CID 13316557.
C15H13F2NO3S; molecular weight 325.3 g/mol.
- Participants / model
- Chemical record
- Follow-up
- Living database
- Study design
- Curated structure record
Formula and molecular weight establish the recorded structure, not the contents of a retail product or an effective dose.
Read the original sourceWhat did the six-person human study establish?
After one 20 mg exposure, researchers detected fladrafinil and its conversion to flmodafinil. They did not test wakefulness, focus, tolerability, or daily use.
The same six volunteers received flmodafinil and fladrafinil three weeks apart. Fladrafinil’s purchased liquid assayed 93.1 mg/mL versus its 100 mg/mL label, and researchers adjusted the administered volume.
Urine parent concentrations peaked at 52 to 111 ng/mL after two or four hours; parent was detectable up to 12 hours, generated flmodafinil up to eight days, and acid/sulfone metabolites up to two weeks. Dried-blood-spot values were sparse. These are assay windows, not plasma half-life or felt-effect duration.
Investigations Into the Metabolism and Elimination of Flmodafinil and Fladrafinil for Sports Drug Testing Purposes.
Primary human metabolism study
Krug O et al. Drug Testing and Analysis. 2026. PMID 42210629. DOI 10.1002/dta.70100.
Six healthy volunteers each received analytically adjusted single 20 mg exposures to flmodafinil and fladrafinil three weeks apart; the study measured blood/urine analytes, not benefit or tolerability.
- Participants / model
- Six healthy volunteers, three women and three men
- Follow-up
- Single exposures separated by three weeks
- Study design
- Within-person two-administration metabolism and anti-doping detection study without placebo
No cognitive, wakefulness, sleep, physical-performance, vital-sign, ECG, laboratory-safety or adverse-event endpoint was reported.
Read the original sourceDoes fladrafinil convert to flmodafinil?
Yes. Generated flmodafinil appeared later in blood and urine, supporting conversion in people.
The study does not establish how much flmodafinil exposure is needed for an effect, interchangeable doses, onset, clinical benefit or safety. Modafinil and armodafinil trials cannot fill those gaps.
Investigations Into the Metabolism and Elimination of Flmodafinil and Fladrafinil for Sports Drug Testing Purposes.
Primary human metabolism study
Krug O et al. Drug Testing and Analysis. 2026. PMID 42210629. DOI 10.1002/dta.70100.
Six healthy volunteers each received analytically adjusted single 20 mg exposures to flmodafinil and fladrafinil three weeks apart; the study measured blood/urine analytes, not benefit or tolerability.
- Participants / model
- Six healthy volunteers, three women and three men
- Follow-up
- Single exposures separated by three weeks
- Study design
- Within-person two-administration metabolism and anti-doping detection study without placebo
No cognitive, wakefulness, sleep, physical-performance, vital-sign, ECG, laboratory-safety or adverse-event endpoint was reported.
Read the original sourceDid Lafon report wakefulness or hypersomnia effects?
The patent reports stimulant-like effects in mice and rats, then asserts “excellent” human results without providing the study needed to evaluate that sentence.
In rodents, selected intraperitoneal doses increased locomotion, shortened barbiturate sleep and restored movement after habituation or hypoxia. The same program also recorded sedation or depressed respiration at some doses and faster convulsion/death after an anoxia challenge at 256 mg/kg.
The human claim gives no sample, diagnosis, comparator, randomization, masking, endpoint, effect size, attrition, harms or citation. The historical term “psychasthenia” does not identify a modern anxiety, depression, fatigue or cognitive disorder.
Substituted benzhydrylsulphinylacetamide derivatives and pharmaceutical compositions containing them.
Original patent disclosure
Lafon Laboratories. US Patent 4,489,095. Filed 1982; published 1984.
The patent reports stimulant-like rodent pharmacology and an undocumented statement of human results at 100 to 150 mg/day; it provides no human denominator, comparator, outcome magnitude or safety table.
- Participants / model
- Male mice and rats in acute experiments; unspecified people in an unsupported narrative claim
- Follow-up
- Acute animal experiments; claimed human exposure of two to eight weeks
- Study design
- Patent experiments and narrative development claim
- Funding
- Patent applicant disclosure.
Patents disclose applicant-selected data and are not peer-reviewed trial reports.
Read the original sourceWhat is known about human safety?
No adequate human safety dataset exists. The metabolism paper contains no formal adverse-event, cardiovascular, psychiatric, laboratory or repeated-dose assessment.
Rodent respiratory, excitation, stimulant-potentiation and worsened-anoxia findings are hazard signals, not human incidence estimates. Dependence, tolerance, withdrawal, liver, skin, reproductive and interaction risks remain unresolved.
Investigations Into the Metabolism and Elimination of Flmodafinil and Fladrafinil for Sports Drug Testing Purposes.
Primary human metabolism study
Krug O et al. Drug Testing and Analysis. 2026. PMID 42210629. DOI 10.1002/dta.70100.
Six healthy volunteers each received analytically adjusted single 20 mg exposures to flmodafinil and fladrafinil three weeks apart; the study measured blood/urine analytes, not benefit or tolerability.
- Participants / model
- Six healthy volunteers, three women and three men
- Follow-up
- Single exposures separated by three weeks
- Study design
- Within-person two-administration metabolism and anti-doping detection study without placebo
No cognitive, wakefulness, sleep, physical-performance, vital-sign, ECG, laboratory-safety or adverse-event endpoint was reported.
Read the original sourceSubstituted benzhydrylsulphinylacetamide derivatives and pharmaceutical compositions containing them.
Original patent disclosure
Lafon Laboratories. US Patent 4,489,095. Filed 1982; published 1984.
The patent reports stimulant-like rodent pharmacology and an undocumented statement of human results at 100 to 150 mg/day; it provides no human denominator, comparator, outcome magnitude or safety table.
- Participants / model
- Male mice and rats in acute experiments; unspecified people in an unsupported narrative claim
- Follow-up
- Acute animal experiments; claimed human exposure of two to eight weeks
- Study design
- Patent experiments and narrative development claim
- Funding
- Patent applicant disclosure.
Patents disclose applicant-selected data and are not peer-reviewed trial reports.
Read the original sourceDoes WADA listing prove it improves performance?
No. Fladrafinil is prohibited in competition as an S6.A non-specified stimulant, but the cited evidence contains no human athletic-performance, strength or endurance trial.
A long analytical detection window can outlast any subjective effect. The 2,000 athlete samples in the metabolism study were all negative, which only describes that tested pool.
The 2026 Prohibited List.
Official sports-regulation record
World Anti-Doping Agency. The 2026 Prohibited List. Effective 1 January 2026.
Flmodafinil and fladrafinil are named S6.A non-specified stimulants prohibited in competition.
- Participants / model
- Athletes subject to the World Anti-Doping Code
- Follow-up
- 2026 list
- Study design
- Official prohibited-substance list
A prohibited classification is a rule consequence, not evidence of improved performance or a quantified medical risk.
Read the original sourceDevelopment and Validation of an Analytical Method to Identify and Quantitate Novel Modafinil Analogs in Products Marketed as Dietary Supplements.
Primary analytical study
Bakota EL et al. Journal of Dietary Supplements. 2025. PMID 39466147.
The method distinguishes modafinil, adrafinil, CRL-40,940 and CRL-40,941; four tested products were labeled as and contained adrafinil.
- Participants / model
- Four products labeled as adrafinil plus analytical standards
- Follow-up
- Cross-sectional product testing
- Study design
- Laboratory method validation and market-sample analysis
The study does not report that the products contained either fluorinated analog and supplies no efficacy or safety result.
Read the original sourceStudies and sources
Investigations Into the Metabolism and Elimination of Flmodafinil and Fladrafinil for Sports Drug Testing Purposes.
Primary human metabolism study
Krug O et al. Drug Testing and Analysis. 2026. PMID 42210629. DOI 10.1002/dta.70100.
Six healthy volunteers each received analytically adjusted single 20 mg exposures to flmodafinil and fladrafinil three weeks apart; the study measured blood/urine analytes, not benefit or tolerability.
- Participants / model
- Six healthy volunteers, three women and three men
- Follow-up
- Single exposures separated by three weeks
- Study design
- Within-person two-administration metabolism and anti-doping detection study without placebo
No cognitive, wakefulness, sleep, physical-performance, vital-sign, ECG, laboratory-safety or adverse-event endpoint was reported.
Read the original sourceFDA analytical method for modafinil analogs
Primary analytical methods poster
US FDA. Development and Validation of an Analytical Method to Identify and Quantitate Novel Modafinil Analogs in Dietary Supplements. 2023.
The method distinguishes modafinil, adrafinil, CRL-40,940, CRL-40,941, and N-methyl-4,4-difluoromodafinil.
- Participants / model
- Chemical standards and supplement analysis
- Follow-up
- Method-development study
- Study design
- LC-HRMS analytical method
Identifying a molecule is not demonstrating an approved indication, efficacy, or safe dose.
Read the original sourcePubChem: fladrafinil chemical identity
Government chemical identity database
National Library of Medicine. PubChem CID 13316557.
C15H13F2NO3S; molecular weight 325.3 g/mol.
- Participants / model
- Chemical record
- Follow-up
- Living database
- Study design
- Curated structure record
Formula and molecular weight establish the recorded structure, not the contents of a retail product or an effective dose.
Read the original sourceSubstituted benzhydrylsulphinylacetamide derivatives and pharmaceutical compositions containing them.
Original patent disclosure
Lafon Laboratories. US Patent 4,489,095. Filed 1982; published 1984.
The patent reports stimulant-like rodent pharmacology and an undocumented statement of human results at 100 to 150 mg/day; it provides no human denominator, comparator, outcome magnitude or safety table.
- Participants / model
- Male mice and rats in acute experiments; unspecified people in an unsupported narrative claim
- Follow-up
- Acute animal experiments; claimed human exposure of two to eight weeks
- Study design
- Patent experiments and narrative development claim
- Funding
- Patent applicant disclosure.
Patents disclose applicant-selected data and are not peer-reviewed trial reports.
Read the original sourceThe 2026 Prohibited List.
Official sports-regulation record
World Anti-Doping Agency. The 2026 Prohibited List. Effective 1 January 2026.
Flmodafinil and fladrafinil are named S6.A non-specified stimulants prohibited in competition.
- Participants / model
- Athletes subject to the World Anti-Doping Code
- Follow-up
- 2026 list
- Study design
- Official prohibited-substance list
A prohibited classification is a rule consequence, not evidence of improved performance or a quantified medical risk.
Read the original sourceDevelopment and Validation of an Analytical Method to Identify and Quantitate Novel Modafinil Analogs in Products Marketed as Dietary Supplements.
Primary analytical study
Bakota EL et al. Journal of Dietary Supplements. 2025. PMID 39466147.
The method distinguishes modafinil, adrafinil, CRL-40,940 and CRL-40,941; four tested products were labeled as and contained adrafinil.
- Participants / model
- Four products labeled as adrafinil plus analytical standards
- Follow-up
- Cross-sectional product testing
- Study design
- Laboratory method validation and market-sample analysis
The study does not report that the products contained either fluorinated analog and supplies no efficacy or safety result.
Read the original sourceWhy is fladrafinil in D tier?
D reflects demonstrated human metabolic conversion and preclinical stimulant plausibility without an appraisable human benefit trial or repeated-use safety dataset. The patent gives no study details that support human efficacy.