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S233.0
S-23 Research
Mostly mechanism / observationalLimited safety
5 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most S-23 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality studies published 2009–2025.
Based on 5 studies
Confidence
Low
By outcome
Androgen & hormonal axis
Mostly mechanism / observational4 studies
Safety profile
Mostly mechanism / observational3 studies
Body composition (rats only)
Too few graded studies1 study
Fertility suppression (contraceptive effect)
Too few graded studies1 study
Active research area
4 studies in the last 5 years
200920172025
1Spermatogenesis suppression and body compositionAnimal2009
This is the first study to show that a selective androgen receptor modulator combined with EB is an effective and reversible regimen for hormonal male contraception in rats.
Jones A, Chen J, Hwang DJ, Miller DD, Dalton JT · Endocrinology (2009)
Foundational S-23 paper — high androgen-receptor binding affinity (Ki ~1.7 nM) and full-agonist activity in vitro
In intact male rats, suppressed LH (>50%) and, with estradiol benzoate, suppressed FSH and spermatogenesis: four of six rats had no sperm and zero pregnancies in mating trials
Increased bone mineral density and lean mass and reduced fat mass dose-dependently — the basis for its grey-market body-composition use
It is shown that SARMs may increase the risk of cardiovascular diseases ... There is a noticeable lack of clinical trials and literature on the relationship between SARMs, cardiovascular diseases, and the AR.
Hall E, Vrolijk MF · Nutrients (2023)
Review of androgen-receptor pharmacology and the cardiovascular risk of abusing SARM-containing supplements
Notes SARM abuse may raise cardiovascular risk via the renin-angiotensin system, lipid profile, inflammation, platelet activity, and other pathways
Emphasizes the near-total absence of clinical trials on SARMs and cardiovascular outcomes
3Label accuracy of SARM-marketed supplementsObservational2021
This study found discrepancies ranging from a supplement in which no active ingredients were found, to supplements containing undeclared prohibited analytes.
Leaney AE, Beck P, Biddle S, Brown P, Grace PB, Hudson SC, Mawson DH · Drug testing and analysis (2021)
Purchased and chemically analyzed consumer products marketed as SARMs (the grey market S-23 is sold in)
Found pervasive mislabeling — products with no active ingredient, undeclared prohibited analytes, and doses differing from the label
No SARM has met the safety/efficacy bar for FDA or EMA approval; products are illegally marketed as supplements
4Urinary detection window of S-23Observational2022
To the best of the authors knowledge, this seems to be the first study ever achieved on S-23 [in humans] ... nothing has been published about long-term effects of S-23.
Ameline A, Gheddar L, Raul JS, Kintz P · Journal of pharmaceutical and biomedical analysis (2022)
Single ~8 mg oral dose of S-23 in one human volunteer, used to characterize urinary metabolites for anti-doping — a detection study, not an efficacy or safety study
S-23 was detectable in urine from 2 h up to 28 days post-administration
Explicitly notes very few data exist and nothing is published on the long-term effects of S-23
5Urinary elimination profile of microdosed S-23Observational2025
Among these, S-23 has been identified in five AAFs reported in 2022 ... inadvertent exposure through contaminated dietary supplements has emerged as a significant concern.
Alhalabi H, Korsmeier L, Thomas A, Thevis M · Biomedical chromatography : BMC (2025)
Microdose (1, 10, 50 µg) human administration study characterizing S-23 urinary elimination for doping control
S-23 was responsible for five adverse analytical findings (positive doping tests) in athletes in 2022
Highlights contaminated dietary supplements as a route of inadvertent S-23 exposure