Read Off Label rates the evidence for S-23 as Very Weak and the benefit magnitude as unclear, producing an overall grade of D (2.9/10). Developed at Kaken Pharmaceutical / GTx as contraceptive.

S-23 has a unknown-high risk profile in published human data. Legal status: NOT FDA-approved; gray market; banned sport. This is not medical advice — see the disclaimer.

S-23

Muscle & Strength · SARM

Tier D

Reviewed by Read Off Label · Last reviewed Jun 8, 2026 · How we grade

anabolicbannedresearch-only

2.9 / 10

Tier D

Ev 2 Bn 5 Sf 3

Bottom line

Read Off Label grades S-23 as D (2.9/10) based on very weak evidence, unclear benefit magnitude, and a unknown-high-risk safety profile.

Developed at Kaken Pharmaceutical / GTx as contraceptive.

Typical use: Typical illicit: 10-30 mg/day PO — NOT FDA-approved; gray market; banned sport.

What this is

Developed at Kaken Pharmaceutical / GTx as contraceptive. Because it fully suppresses spermatogenesis at moderate doses, 'SARM-like' billing is misleading — closer to an AAS in effect. Limited popularity due to severity of side effect profile.

Mechanism

Strong SARM with high AR binding and full agonist activity in androgenic tissues; originally developed as male hormonal contraceptive candidate

Dose & route

Typical illicit: 10-30 mg/day PO

Citations

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Common questions

Does S-23 work?: Read Off Label rates the evidence for S-23 as Very Weak and the benefit magnitude as unclear, producing an overall grade of D (2.9/10). Developed at Kaken Pharmaceutical / GTx as contraceptive.
Is S-23 safe?: S-23 has a unknown-high risk profile in published human data. Legal status: NOT FDA-approved; gray market; banned sport. This is not medical advice — see the disclaimer.
What is the typical dose for S-23?: Typical illicit: 10-30 mg/day PO
How does S-23 work?: Strong SARM with high AR binding and full agonist activity in androgenic tissues; originally developed as male hormonal contraceptive candidate

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.