aminotadalafil
updated
Aminotadalafil is a modified form of tadalafil found undeclared in adulterated supplements, including a product flagged by Singapore's regulator. It is sometimes described as a permanent PDE5 inhibitor, a claim that comes from a concern about its chemical structure rather than a measured effect. Several laboratories can detect it, but no study has tested erectile function, a dose or safety in people, and the regulator said its adverse effects are not established. Graded F because it is found in hidden-drug products with no established benefit or safe exposure.
Small-molecule tadalafil analog
- Singapore HSA identified it together with another undeclared analog in S Lion Juice 1.
- The regulator explicitly said the analogs’ adverse effects were not established.
- A chemical identity and a product warning do not establish an effective or safe dose.
What is aminotadalafil?
Aminotadalafil is a modified tadalafil compound. It differs from tadalafil and from the separately named analog acetaminotadalafil.
source: PubChem: aminotadalafil chemical identity, National Library of Medicine. PubChem CID 10178467.
source: Simultaneous HPLC-MS identification of aminotadalafil and other adulterants, Tagami T, Takeda A, Asada A, Aoyama A, Doi T, Kajimura K, Sawabe Y. Simultaneous identification of hydroxythiohomosildenafil, aminotadalafil, thiosildenafil, dimethylsildenafil, and thiodimethylsildenafil in dietary supplements using high-performance liquid chromatography-mass spectrometry. Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan. 2013. DOI 10.3358/shokueishi.54.232.
What evidence exists beyond product alerts?
Several laboratories have identified aminotadalafil or validated methods to detect it. These analytical studies do not test erectile function, dosing, or safety in people.
A 2024 Chinese method covered 90 analytes and tested 286 batches. Its eight positive batches involved other PDE5-related compounds; including aminotadalafil in the test panel does not mean it was found in those batches.
An immunoassay IC50 measures antibody recognition. It is not the concentration needed to inhibit PDE5. HSA’s S Lion Juice finding involved both aminotadalafil and thiodimethylsildenafil, so the mixed product cannot supply a clean compound-specific effect or injury rate.
source: LC-ion-trap/time-of-flight screening, 2020, Kim U, Cho HD, Kang MH, Suh JH, Eom HY, Kim J, Seo S, Kim G, Koo HR, Ha N, Song UT, Han SB. Screening of Phosphodiesterase-5 Inhibitors and Their Analogs in Dietary Supplements by Liquid Chromatography-Hybrid Ion Trap-Time of Flight Mass Spectrometry. Molecules (Basel, Switzerland). 2020. DOI 10.3390/molecules25122734.
source: Simultaneous HPLC-MS identification of aminotadalafil and other adulterants
source: Chinese 90-analyte supplement screen, 2024, Jin S, Wang Y, Ning X, Liu T, Liang R, Pei X, Cao J. UPLC-MS/MS-Based Target Screening of 90 Phosphodiesterase Type 5 Inhibitors in 5 Dietary Supplements. Molecules (Basel, Switzerland). 2024. DOI 10.3390/molecules29153601.
source: Chinese immunoassay method, Yang JY, Xie MC, Tan XC, Tian YX, Wang H, Xu ZL, Yuan TT, Xiao YM, Shen YD. Improved molecular softness of tadalafil hapten enhancing antibody performance in immunoassay: Evidence from computational chemistry. Journal of food science. 2022. DOI 10.1111/1750-3841.16078.
source: HSA S Lion Juice product finding, Health Sciences Authority, Singapore. S Lion Juice product alert. August 14, 2015.
Does it permanently inhibit PDE5?
That has not been demonstrated by the cited evidence. The original RIVM discussion says a chemical group may cause permanent enzyme inhibition; later accounts often state the concern too confidently.
The cited records contain no exact-compound functional result, human duration study or clinical PK result to validate that claim. Product adulteration and uncertain analog effects remain sufficient concerns without inventing irreversible pharmacology or a measured rate of harm.
source: RIVM 2007 unapproved PDE5-inhibitor report, RIVM 2007 unapproved PDE5-inhibitor report. https://www.rivm.nl/bibliotheek/rapporten/370030001.pdf
source: HSA S Lion Juice product finding
Studies and sources
HSA S Lion Juice product finding
Official scientific or regulatory record
Health Sciences Authority, Singapore. S Lion Juice product alert. August 14, 2015.
The implicated product contained aminotadalafil and thiodimethylsildenafil. The regulator warned about hidden potent ingredients and uncertain analogue adverse effects. The record establishes an adulteration hazard, not a clean aminotadalafil adverse-event denominator.
- Participants / model
- Marketed mixed-ingredient products
- Follow-up
- August 2015
- Study design
- Regulatory laboratory analysis and alert
Simultaneous HPLC-MS identification of aminotadalafil and other adulterants
Analytical identity or detection study
Tagami T, Takeda A, Asada A, Aoyama A, Doi T, Kajimura K, Sawabe Y. Simultaneous identification of hydroxythiohomosildenafil, aminotadalafil, thiosildenafil, dimethylsildenafil, and thiodimethylsildenafil in dietary supplements using high-performance liquid chromatography-mass spectrometry. Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan. 2013. DOI 10.3358/shokueishi.54.232.
The study separates and identifies several chemically distinct adulterants. Quantification performance depends on the matrix and method; the existence of a detected chromatographic peak establishes neither biological efficacy nor safety.
- Participants / model
- Chemical standards and supplement testing
- Follow-up
- Method-development study
- Study design
- HPLC-MS analytical method
PubChem: aminotadalafil chemical identity
Government chemical identity database
National Library of Medicine. PubChem CID 10178467.
C21H18N4O4; molecular weight 390.4 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 sourceRIVM 2007 unapproved PDE5-inhibitor report
Official scientific or regulatory record
RIVM 2007 unapproved PDE5-inhibitor report. https://www.rivm.nl/bibliotheek/rapporten/370030001.pdf
RIVM describes a chemical group that may cause permanent inhibition of enzymes. This is a mechanistic concern, not measured irreversible PDE5 inhibition, a human exposure study or proof of prolonged erection.
Read the original sourceLC-ion-trap/time-of-flight screening, 2020
Analytical identity or detection study
Kim U, Cho HD, Kang MH, Suh JH, Eom HY, Kim J, Seo S, Kim G, Koo HR, Ha N, Song UT, Han SB. Screening of Phosphodiesterase-5 Inhibitors and Their Analogs in Dietary Supplements by Liquid Chromatography-Hybrid Ion Trap-Time of Flight Mass Spectrometry. Molecules (Basel, Switzerland). 2020. DOI 10.3390/molecules25122734.
The paper validates identification of PDE5-related analytes in supplement matrices. Its background repeats the permanent-inhibition concern using stronger wording while referring to prior reviews/government material. Analytical recovery and precision are method performance, not drug potency or therapeutic efficacy.
Read the original sourceChinese 90-analyte supplement screen, 2024
Analytical identity or detection study
Jin S, Wang Y, Ning X, Liu T, Liang R, Pei X, Cao J. UPLC-MS/MS-Based Target Screening of 90 Phosphodiesterase Type 5 Inhibitors in 5 Dietary Supplements. Molecules (Basel, Switzerland). 2024. DOI 10.3390/molecules29153601.
Investigators validated a 90-analyte method and tested 286 product batches; eight were positive, involving sildenafil, 2-hydroxypropylnortadalafil and N-ethyltadalafil. Aminotadalafil’s inclusion in the target/validation panel is not a positive aminotadalafil exposure or efficacy finding.
Read the original sourceChinese immunoassay method
Analytical identity or detection study
Yang JY, Xie MC, Tan XC, Tian YX, Wang H, Xu ZL, Yuan TT, Xiao YM, Shen YD. Improved molecular softness of tadalafil hapten enhancing antibody performance in immunoassay: Evidence from computational chemistry. Journal of food science. 2022. DOI 10.1111/1750-3841.16078.
An immunochemical detection IC50 describes antibody recognition in that assay. It does not measure inhibition of PDE5-mediated cGMP hydrolysis. These numbers do not measure relative pharmacological potency.
This assay record does not describe a therapeutic experiment.
Read the original sourceWhy is aminotadalafil in F tier?
F: found in hidden-drug products, with no established clinical benefit or safe exposure. The permanent-inhibition claim remains a concern about its chemical structure rather than demonstrated PDE5 pharmacology. The grade does not quantify its toxicity.
how tiers are graded: methodology · every cited source · about reptides.
Research reference, not medical advice. Entries distinguish product labels, study doses and reported protocols. Check the linked source for the product, route and population.