S-23 — Dosing, Cycles, Half-Life & Side Effects

S-23 is a selective androgen receptor modulator (SARM) with a half-life of 12 hours. Aryl-propionamide SARM investigated as male contraceptive: 96% oral bioavailability in rats, dose-dependent muscle/bone anabolism with prostate-sparing tissue selectivity. Only SARM with published preclinical evidence of fully reversible azoospermia (Jones 2008) — most HPTA-suppressive SARM characterized. No human PK study. Primary risks include strong HPTA suppression. This page is educational harm-reduction reference compiled from peer-reviewed literature — not medical advice, not an endorsement, not a recommendation to use. Consult a licensed clinician before any decision.

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Quick Facts

Class	Selective Androgen Receptor Modulator
Half-life	12 hours
Detection window	14 days
Aromatization	No
Hepatotoxicity	Low
Suppression	9/10
17α-alkylated	No
Administration	oral

Typical Dosing Ranges

Common dose range: 10-30mg/day

Cycle length: 8-10 weeks

Time to steady state: ~2.5 days

Dose ranges are compiled from published pharmacokinetic studies and community-reported usage. Where a value is community-reported rather than clinically studied, this page and its structured data flag it. Lower end of any range is always the safer starting point.

Stacking Considerations

No structural stacking blockers. Standard harm-reduction rules apply: minimize total androgen load, minimize oral exposure, and monitor bloodwork.

PCT Requirements

This compound causes clinically meaningful HPTA suppression. Post-cycle therapy is recommended.
Depot clearance estimate: ~3 days post-last-dose before SERM start (5 × apparent depot half-life of 12h).
Never stack two SERMs. Extend a single SERM (tamoxifen OR enclomiphene/clomiphene) rather than combining.
Use the cycle planner to generate a full protocol based on your complete stack, not this compound alone.

Side Effect Profile

Significant suppression
Vision tint (rare)
Limited research
May reduce HDL

Known Interactions

RAD-140 (Testolone) + s23
moderate — suppressive
S23 is highly suppressive. Combination may cause significant hormonal disruption.
Recommendation: Test base strongly recommended. PCT required.
Monitor: Full hormone panel

Monitoring (Bloodwork & Vitals)

Comprehensive metabolic panel (baseline, mid-cycle, post-cycle)
Lipid panel (total cholesterol, HDL, LDL, triglycerides)
CBC (hemoglobin, hematocrit — watch for erythrocytosis)
Sex-hormone panel (Total T, Free T, Estradiol sensitive, SHBG, LH, FSH)
Blood pressure (weekly self-check; flag systolic >140 or diastolic >90)

Baseline bloodwork is recommended before any cycle. Discontinue if liver enzymes exceed 3× upper limit of normal or if hematocrit exceeds 54%.

Frequently Asked Questions

What is the half-life of S-23?

S-23 has a half-life of approximately 12 hours. Clearance estimate: 12h × 5 = 60h = 2.5 days. This figure is used to determine injection frequency (for esters) and post-cycle clearance timing.

What is the typical dose range for S-23?

Commonly reported ranges for S-23: 10-30mg/day. Cycle length: 8-10 weeks. These are compiled from published studies and community-reported usage — individual response varies and lower end is always preferred.

Does S-23 suppress natural testosterone?

S-23 causes severe suppression of the HPTA axis (score 9/10). Post-cycle therapy (PCT) is recommended after use.

Is S-23 liver toxic?

Hepatotoxicity rating: Low. Non-17αα compound — liver stress is lower but still warrants periodic monitoring during a cycle.

Does S-23 aromatize to estrogen?

Aromatization profile: No. Minimal to no aromatization expected, so aromatase inhibitors are not typically indicated for this compound alone.

What is S-23 typically used for?

S-23 is commonly used for: Cutting, Recomposition, Advanced SARM users. Intended-use context does not imply safety — every use case carries the same underlying pharmacological risks.

Citations

Disclaimer

StackItSmart is an independent harm-reduction reference. The content above is compiled from peer-reviewed literature and is not medical advice, not an endorsement, and not a recommendation to use S-23. Performance-enhancing compounds carry legal, endocrine, cardiovascular, and hepatic risks. Consult a licensed clinician before any decision. StackItSmart does not provide sourcing, procurement, or dosing prescriptions.