GTx Developed • Male Contraceptive • Strongest SARM

S-23: The Strongest SARM Ever

By , HighPeptides Editor

Closest SARM to actual anabolic steroids. 100% reversible infertility in rats (male contraceptive research). GTx developed it, human trials never happened. Very suppressive. Here's the research.

0
Common Research Dose
(Daily)
0
Infertility in Rats
(Reversible)
0
Elimination Half-Life
(Daily Dosing)
📋 On this page
  1. How S-23 Works
  2. What the Research Shows
  3. Side Effects & Risks
  4. Key Takeaways
  5. 🔬 Verified Research Source
  6. 🛒 Recommended Products
  7. More SARM Research
⚠️ Regulatory Status Warning

S-23 is NOT FDA approved. It was investigated by GTx as a male contraceptive but human trials never happened. Very limited human safety data exists.

All SARMs are banned by WADA. This page is for educational purposes only.

NOT FDA APPROVED WADA BANNED

Mechanism

How S-23 Works

Developed by GTx (same as Ostarine). Highest anabolic potency of any SARM. Investigated as male hormonal contraceptive — produces reversible infertility.

💪
Highest Anabolic Potency
S-23 has the highest anabolic:androgenic ratio of any SARM, making it the closest to actual steroids in terms of muscle-building potential. This also means more suppression and side effects.
🎯
Male Contraceptive Research
GTx investigated S-23 as a male hormonal contraceptive. In rat studies, it produced 100% reversible infertility by suppressing gonadotropins and spermatogenesis. Fertility returned after cessation.
🧪
GTx Development
Same company that developed Ostarine. S-23 was their "next generation" SARM with higher potency. Human trials were planned but never materialized. Compound was shelved.
⚠️
Very Suppressive
Significant testosterone suppression expected at research doses. The contraceptive mechanism itself is based on suppressing the HPG axis. Recovery may require PCT.
Research Data

What the Research Shows

Anabolic:Androgenic Ratio (vs Testosterone)
Highest of any SARM — closest to actual steroids
Spermatogenesis Suppression (Rats)
100% reversible infertility in male contraceptive study
Testosterone Suppression
Expected to be very significant at research doses
Safety

Side Effects & Risks

⚠️ Major Concerns
  • Very significant testosterone suppression
  • Potential prostate effects (estrogenic)
  • HPG axis suppression for contraception
  • Limited human safety data
  • Unknown long-term effects
Other Effects
  • Water retention likely
  • Acne and oiliness possible
  • Hair loss risk (potent)
  • Lipid profile changes
  • Fatigue during suppression
Bottom Line

Key Takeaways

✅ What We Know
  • Highest anabolic potency SARM
  • 100% reversible infertility in rats
  • Developed by GTx (Ostarine creators)
  • 12-hour half-life
⚠️ What We DON'T Know
  • Human safety data
  • Optimal dosing
  • Long-term effects
  • Recovery timeline

🔬 Verified Research Source

Third-party tested compounds from Swiss Chems — one of the most trusted research suppliers.

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Supplies
🛡️ TUDCALiver support🌿 AshwagandhaPCT support💊 ZMAHormonal support
Related

More SARM Research

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Ostarine Guide
Most researched
⚡
RAD-140 Guide
High potency
⚠️ Disclaimer

Educational only. S-23 is NOT FDA approved. Limited human data. Banned by WADA. Male contraceptive research was in rats only. Consult healthcare provider.