# S-23

*Also known as: S23*

Suppressive SARM explored for male contraception; short half-life.

## Overview

S-23 is a non-steroidal selective androgen receptor modulator originally investigated as a candidate male hormonal contraceptive. It binds the androgen receptor with high affinity and strong tissue selectivity, producing pronounced anabolic effects in muscle while markedly suppressing gonadotropins, which is the mechanism behind its contraceptive interest. The compound has a short roughly 4-hour half-life, requiring divided twice-daily oral dosing, and solid human pharmacokinetic data are absent, so the model is approximate. It is among the most suppressive SARMs studied, with rapid reductions in luteinizing hormone, follicle-stimulating hormone, and endogenous testosterone, and a bis-hydroxylated long-term metabolite is detectable in urine for roughly three weeks. As an investigational, unapproved compound that is WADA-prohibited and frequently sold mislabeled or contaminated, harm reduction prioritizes understanding that suppression is severe and reversible only with a structured PCT, alongside third-party testing and on-cycle bloodwork (LH, FSH, total T, lipids, ALT/AST).

## Pharmacokinetics

- **Model tier:** simple
- **Half-life:** 0.2 days (4 hours)
- **Bioavailability:** 100%

## Dosing

- **Default dose:** 15 mg
- **Typical range:** 5–30 mg
- **Units:** ng/mL

## Harm reduction

- **Aromatizes:** No
- **Hepatotoxicity:** mild
- **Injection frequency:** Oral, 2×/day
- **Interaction notes:** Highly suppressive; investigated as a male contraceptive.

## Detection time (anti-doping)

- **Window:** 15–21 days post-last-dose
- **Target metabolite:** Bis-hydroxylated metabolite
- **Assay:** LC-HRMS/MS
- **Notes:** Bis-hydroxylated long-term metabolite detectable ~20.5 days.

## Source

- **Label:** PMC S-23
- **URL:** https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2630904/
- **Notes:** No good PK sources.

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**Canonical URL:** https://anabolicdex.com/compounds/s23
**Plot:** https://anabolicdex.com/plot?compound=s23