What does the evidence show about S-23's effects?

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.

What safety findings are reported for S-23?

S-23 has a unknown-high risk profile in the database. Unknown-High (strongest HPG suppression of common SARMs; fertility effects — the original intended indication) Legal status: NOT FDA-approved; gray market; banned sport.

What does the low Safety score for S-23 represent?

The Safety score is 3/10. It records the substantial harms described for one or more use contexts; the Benefit score, indication, dose, route, duration, population, and legal status remain separate parts of the evidence profile.

Rankings / Muscle & Strength

S-23

Muscle & Strength · SARM

Tier D

High-risk evidence profile

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

anabolicbannedresearch-only

High-risk evidence profile

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.

Its high-risk evidence profile reflects a Safety score of 3/10; reported benefits and harms can differ by indication, dose, route, duration, and population.

Developed at Kaken Pharmaceutical / GTx as contraceptive.

Studied, labeled, or reported-use context: Typical illicit: 10-30 mg/day PO — NOT FDA-approved; gray market; banned sport; not individualized guidance.

Citation correction in progress

1 PubMed link was found to be unrelated to this entry and removed from public output. The remaining sources are shown below, but this row's claims and score still need a full source-by-source revalidation.

What the evidence says

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

Studied, labeled, or reported dose & route

Typical illicit: 10-30 mg/day PO

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

A link means the source informed this entry; it does not mean every claim on the page comes from that source. If a citation looks wrong or you want a claim re-checked, send a correction.

Common questions

What does the evidence show about S-23's effects?: 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.
What safety findings are reported for S-23?: S-23 has a unknown-high risk profile in the database. Unknown-High (strongest HPG suppression of common SARMs; fertility effects — the original intended indication) Legal status: NOT FDA-approved; gray market; banned sport.
What does the low Safety score for S-23 represent?: The Safety score is 3/10. It records the substantial harms described for one or more use contexts; the Benefit score, indication, dose, route, duration, population, and legal status remain separate parts of the evidence profile.
What doses or routes are reported for S-23?: Typical illicit: 10-30 mg/day PO This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
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.