Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| LGD-4033 (Ligandrol) | S-23 | |
|---|---|---|
| Category | SARMs | SARMs |
| Standard Dose | Research indicates 5-10 mg daily orally for 8-12 weeks. Phase 1 data showed significant lean mass gains at 1 mg/day. | Research indicates 10-25 mg daily orally for 8-12 weeks. No human clinical trials — dosing extrapolated from rat pharmacology and anecdotal reports. |
| Timing | Once daily, consistent timing. Half-life approximately 24-36 hours. No food timing requirements. | Split into 2 daily doses due to relatively short half-life (~12 hours). Morning and evening dosing. |
| Cycle Duration | 8-12 week cycles maximum. PCT strongly recommended after all but the shortest/lowest-dose cycles. | 8 week cycles maximum recommended. PCT is absolutely mandatory due to profound HPG suppression. Allow full recovery before considering subsequent cycles. |
| Evidence Level | moderate_human | animal_plus_anecdotal |
LGD-4033 is a potent nonsteroidal selective androgen receptor modulator with high AR binding affinity (Ki of approximately 1 nM). It demonstrates strong anabolic activity in muscle and bone with significantly reduced androgenic activity in prostate tissue, achieving an anabolic-to-androgenic ratio of approximately 10:1. LGD-4033 activates the AR with full agonist efficacy in muscle, upregulating the PI3K/Akt/mTOR pathway for protein synthesis and satellite cell recruitment. It produces dose-dependent suppression of SHBG, total testosterone, LH, and FSH, indicating significant HPG axis suppression even at low doses.
Research indicates 5-10 mg daily orally for 8-12 weeks. Phase 1 data showed significant lean mass gains at 1 mg/day.
Once daily, consistent timing. Half-life approximately 24-36 hours. No food timing requirements.
8-12 week cycles maximum. PCT strongly recommended after all but the shortest/lowest-dose cycles.
S-23 is one of the most potent nonsteroidal SARMs developed, originally investigated by GTx, Inc. as a potential male hormonal contraceptive. It binds the androgen receptor with very high affinity, producing near-steroidal anabolic effects in muscle and bone while profoundly suppressing FSH and LH, leading to oligospermia and azoospermia in animal models. S-23 increases lean body mass and bone mineral density while reducing fat mass in a dose-dependent manner. The contraceptive effect was fully reversible in rat studies — spermatogenesis and fertility recovered completely after a 100-day washout period.
Research indicates 10-25 mg daily orally for 8-12 weeks. No human clinical trials — dosing extrapolated from rat pharmacology and anecdotal reports.
Split into 2 daily doses due to relatively short half-life (~12 hours). Morning and evening dosing.
8 week cycles maximum recommended. PCT is absolutely mandatory due to profound HPG suppression. Allow full recovery before considering subsequent cycles.
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