S-23
S23
Suppressive SARM explored for male contraception; short half-life.
Key takeaways
- The most suppressive SARM in the dataset; studied in rats as a male contraceptive candidate.
- Short ~4-hour half-life, so reported protocols split doses twice daily.
- No human trials exist; all efficacy and safety data are animal-derived.
- Long-term metabolite detectable in urine for roughly three weeks.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| Physique (community) | 10–30 mg split into 2 doses | Oral | Twice daily | 6–8 weeks |
Pharmacokinetic summary
- Model tier
- Simple (t½ + F, Tmax estimated)
- Half-life
- 4 hours
- Bioavailability
- 100%
- Typical dose
- 5–30 mg
Harm reduction
- Aromatizes
- No
- Hepatotoxicity
- mild
- Injection frequency
- Oral, 2×/day
⚠ Highly suppressive; investigated as a male contraceptive.
Frequently asked questions
Is S-23 really a male contraceptive?
It was studied as one in rats: the 2009 Endocrinology study showed near-complete, reversible suppression of sperm production. No human trials followed, so calling it a contraceptive overstates what the evidence supports.
How suppressive is S-23?
By animal data and community reports, it's the most suppressive SARM in the dataset, with rapid drops in LH, FSH, and testosterone. Full suppression is treated as a given, so PCT planning and bloodwork aren't optional.
How long is S-23 detectable?
A bis-hydroxylated metabolite is detectable in urine for roughly 20 days by high-resolution mass spectrometry. It's WADA-prohibited, and tested athletes should treat the detection window as about three weeks.
References
- PMC S-23 — No good PK sources.
- Preclinical characterization of S-23, Endocrinology 2009 — Rat study showing reversible suppression of spermatogenesis; basis of the male-contraceptive interest.
Related compounds
Comments
Loading comments…