S-23 A preclinical arylpropionamide with contraception animal data and almost no human efficacy package

01 Names and chemistry

S-23 is an arylpropionamide-class SARM ((2S)-N-(4-cyano-3-trifluoromethylphenyl)-3-(3-fluoro-4-chlorophenoxy)-2-hydroxy-2-methylpropanamide in the analytical literature). It is not enobosarm, not ligandrol, not RAD140, and not Cardarine. Open PubMed counts for careful "S-23" AND (SARM OR androgen) queries were on the order of nineteen records at harvest — among the thinnest surfaces in this commission.

02 Preclinical pharmacology and contraception models

Jones et al. (PMID 18772237) and related preclinical characterisation describe anabolic activity with spermatogenesis suppression in animal contraception designs. That is a rodent/animal reproductive pharmacology finding. It is not a human male contraceptive trial, not a fertility counselling document, and not a physique protocol.

03 Human record — mostly analytical

In-vitro human liver microsome metabolite characterisation and a voluntary single-administration excretion study with analytical follow-up (PMID 35182830; related work PMID 20967890) exist to support doping control. Equine metabolism studies of RAD140 and S-23 enlarge the detection map (PMID 32853476). These papers confirm that S-23 entered the anti-doping problem set. They do not establish therapeutic efficacy or long-term safety in humans.

PubMed-count noise from unrelated “S-23” strings (older receptor or peptide papers) is filtered by requiring SARM / androgen context before admission.

04 Safety inference limits

Class LiverTox and SARM DILI reviews may list S-23 among consumer names; a dense S-23-specific clinical DILI series was not the harvest centre of gravity. Absence of indexed cases is not proof of hepatic safety. No FDA-approved indication exists; WADA S1 listing covers SARMs as a class.

05 Absences

No peer-reviewed human lean-mass RCT. No approved indication. No admitted long-term safety programme. Forum cycle lore is refused.

06 Harvest literature map

Deep-harvest strata for S-23: (1) Jones et al. preclinical contraception / anabolic characterisation; (2) in-vitro metabolite maps; (3) limited human excretion analytical study; (4) equine co-studies with RAD140. PubMed careful count ~19. Tavily commercial pages claiming human muscle/fat outcomes were treated as marketing, not evidence. No therapeutic RCT was found.

How this document was assembled

Commissioned 5 August 2026 in the Adjacent Compounds / SARMs group and rewritten the same day after a deep research-API harvest (Tavily, Exa, PubMed E-utilities, ClinicalTrials.gov API v2, Camoufox for selected primary pages). Artefacts live under projects/adjacent_compounds_research_2026/deep_harvest/. HOUSE_STYLE governs presentation. PubMed-indexed references are NCBI-resolved.

Evidence handling

Study type is named in the reporting sentence. Animal and in-vitro results are not phrased as human outcomes. Sponsor press is secondary until peer-reviewed full text is admitted. Consumer case reports are grey-market exposure literature unless product analytics accompany the report. Cardarine is never called a SARM.

References

1. Alhalabi H, Korsmeier L, Thomas A, Thevis M. Investigations Into the Urinary Metabolite Elimination Profile of the Selective Androgen Receptor Modulator S-23 in Studies Mimicking Contaminated Product Ingestion for Doping Control Purposes. Biomed Chromatogr. 2025;39(6):e70090.
   PMID 40277337 · doi:10.1002/bmc.70090 · PMC12023825
2. Ameline A, Gheddar L, Raul JS, Kintz P. In vitro characterization of S-23 metabolites produced by human liver microsomes, and subsequent application to urine after a controlled oral administration. J Pharm Biomed Anal. 2022;212:114660.
   PMID 35182830 · doi:10.1016/j.jpba.2022.114660
3. Jones A, Chen J, Hwang DJ, Miller DD, Dalton JT. Preclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception. Endocrinology. 2009;150(1):385-95.
   PMID 18772237 · doi:10.1210/en.2008-0674 · PMC2630904
4. Leciejewska N, Jędrejko K, Gómez-Renaud VM, Manríquez-Núñez J, Muszyńska B, Pokrywka A. Selective androgen receptor modulator use and related adverse events including drug-induced liver injury: Analysis of suspected cases. Eur J Clin Pharmacol. 2024;80(2):185-202.
   PMID 38059982 · doi:10.1007/s00228-023-03592-3 · PMC10847181
5. So YM, Wong JKY, Choi TLS, Prabhu A, Stewart B, Farrington AF, et al.. Metabolic studies of selective androgen receptor modulators RAD140 and S-23 in horses. Drug Test Anal. 2021;13(2):318-337.
   PMID 32853476 · doi:10.1002/dta.2920
6. Solomon ZJ, Mirabal JR, Mazur DJ, Kohn TP, Lipshultz LI, Pastuszak AW. Selective Androgen Receptor Modulators: Current Knowledge and Clinical Applications. Sex Med Rev. 2019;7(1):84-94.
   PMID 30503797 · doi:10.1016/j.sxmr.2018.09.006 · PMC6326857
7. Thevis M, Gerace E, Thomas A, Beuck S, Geyer H, Schlörer N, et al.. Characterization of in vitro generated metabolites of the selective androgen receptor modulators S-22 and S-23 and in vivo comparison to post-administration canine urine specimens. Drug Test Anal. 2010;2(11-12):589-98.
   PMID 20967890 · doi:10.1002/dta.211
8. U.S. Food and Drug Administration. Consumer updates and warning letters on body-building products containing SARMs. Regulatory context.
   https://www.fda.gov/
9. World Anti-Doping Agency. Prohibited List — S1 Anabolic Agents (selective androgen receptor modulators).
   https://www.wada-ama.org/
10. NIDDK LiverTox. Selective Androgen Receptor Modulators (SARMs). NCBI Bookshelf NBK619971.
    https://www.ncbi.nlm.nih.gov/books/NBK619971/
11. ClinicalTrials.gov. Protocol inventory via API v2; not peer-reviewed results.
    https://clinicaltrials.gov/
12. PubChem compound summary pages used for identity cross-checks.
    https://pubchem.ncbi.nlm.nih.gov/