SARMSARMNon-steroidalOral

S-23

Also known as S23

Written by enwyReviewed 15 Jul 20261 sources0 comments

S-23 is a potent non-steroidal SARM studied in animals partly as a candidate for male hormonal contraception because it strongly suppresses sperm production. Human data are absent. It is considered one of the more suppressive SARMs anecdotally, with the usual lipid and endocrine downsides and no established dosing.

01 Overview

S-23 was investigated preclinically by GTx, including work on reversible male contraception, since in male rats it suppressed spermatogenesis and gonadotropins while maintaining libido; effects were reversible after cessation. It has high androgen-receptor binding and good oral bioavailability in animal models.

No human trials exist. Recreationally it is regarded as strongly suppressive, and users often report the need for careful post-cycle recovery. It is unapproved, prohibited in sport, and sold only as a research chemical, with all dosing extrapolated from anecdote.

02 Mechanism

High-affinity non-steroidal androgen-receptor agonist; in animals it suppresses LH, FSH and spermatogenesis while retaining anabolic activity.

03 Dosing

Tier	Dose	Route	Notes
Light	10–15 mg/day	Oral	Anecdotal only; no human dosing data.
Common	15–30 mg/day	Oral	Higher anecdotal range; strongly suppressive.

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Increased lean mass and bone densityAnimal studies show anabolic effects on muscle and bone.		Preclinical
Muscle hardness and strengthUsers report pronounced hardening and strength; no human trials.		Anecdotal

05 Side effects

Effect	Severity	Frequency	Evidence
Testosterone and spermatogenesis suppressionIn animals S-23 strongly suppresses gonadotropins and sperm production; reversible on cessation. Human suppression is assumed pronounced.	Severe	Near-universal	Preclinical
Lipid changes (HDL reduction)Reported HDL reductions consistent with potent androgenic action.	Moderate	Common	Anecdotal
Mood changes and aggressionSome users report irritability or heightened aggression; unverified.	Mild	Uncommon	Anecdotal

06 Legal status

United States

Not FDA-approved; unlawful as dietary supplement

as of

United Kingdom

Not licensed as a medicine

as of

07 References

S-23 as a candidate for male contraception (preclinical)PubMed

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.