S-23 is an oral selective androgen receptor modulator (SARM) from the same Ohio State research group that studied andarine. It was studied in rats as a possible male contraceptive, has no published human trial, and is not FDA approved.
Also known as: S23.
For S-23, there is no approved product and no published human trial, so there are no label strengths or studied human amounts.
S-23 is not FDA approved, and we could not find any published trial that gave it to people. FDA says SARMs are unapproved drugs that cannot be legally marketed in the US as dietary supplements or drugs, and lists risks including liver injury and acute liver failure, a higher risk of heart attack or stroke, and effects on fertility. The World Anti-Doping Agency (WADA) names it on its 2026 Prohibited List as a SARM under "other anabolic agents" (S1.2), banned in and out of competition.
In male rats (Jones 2009), S-23 cut LH by more than half, shrank the prostate and grew the levator ani muscle. Given with estradiol for up to 10 weeks, it stopped sperm production in 4 of 6 rats and none of the treated rats sired a pregnancy; fertility came back fully after stopping. It also raised bone density and lean mass and lowered fat mass. Rat results often do not carry over to people.
In an anti-doping study where one volunteer took a single dose (Ameline 2022), S-23 was found in urine for up to 28 days. The authors noted that nothing has been published about its long-term effects.
We could not find a published human half-life or time to peak. In one volunteer given a single dose (Ameline 2022), S-23 was detectable in urine from 2 hours to 28 days later, which shows it lingers but is not a half-life.
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