Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Ostarine (MK-2866 / Enobosarm) | RAD-140 (Testolone) | |
|---|---|---|
| Category | SARMs | SARMs |
| Standard Dose | Research indicates 10-25 mg daily orally for 8-12 weeks. Phase 2 clinical trials used 1-3 mg/day with significant lean mass gains. | Research indicates 10-20 mg daily orally for 8-12 weeks. Phase 1 clinical trial (oncology) identified 100 mg as the maximum tolerated dose. |
| Timing | Once daily, morning or evening. Consistent timing. Half-life approximately 24 hours. No food timing requirements. | Once daily, consistent timing. Very long half-life (~60 hours) means stable plasma levels even with once-daily dosing. Morning preferred. |
| Cycle Duration | 8-12 week cycles. PCT may be required depending on suppression level and cycle length. | 8-12 week cycles. PCT mandatory due to significant HPG axis suppression. |
| Evidence Level | moderate_human | animal_plus_anecdotal |
Ostarine (enobosarm/GTx-024) is a nonsteroidal selective androgen receptor modulator that binds the androgen receptor with high affinity, inducing a conformational change that recruits coactivator proteins preferentially in muscle and bone tissue over prostate and seminal vesicles. This tissue selectivity arises from differential AR cofactor recruitment and 5-alpha reductase metabolism. Ostarine promotes lean body mass by activating AR-mediated transcription of anabolic genes (MYC, IGF-1) in myocytes while minimizing androgenic effects in reproductive tissues. It has demonstrated dose-dependent increases in lean mass in Phase 2 trials.
Research indicates 10-25 mg daily orally for 8-12 weeks. Phase 2 clinical trials used 1-3 mg/day with significant lean mass gains.
Once daily, morning or evening. Consistent timing. Half-life approximately 24 hours. No food timing requirements.
8-12 week cycles. PCT may be required depending on suppression level and cycle length.
RAD-140 is a potent nonsteroidal SARM with high oral bioavailability and selectivity for muscle and bone AR over prostate. It acts as a full agonist at the AR in muscle tissue, promoting nitrogen retention and protein synthesis via mTOR/p70S6K pathway activation. RAD-140 also demonstrates neuroprotective properties, acting against beta-amyloid-induced neurotoxicity through AR-mediated MAPK/ERK signaling. Preclinical data show greater anabolic potency than testosterone propionate at equivalent doses with significantly reduced prostate stimulation.
Research indicates 10-20 mg daily orally for 8-12 weeks. Phase 1 clinical trial (oncology) identified 100 mg as the maximum tolerated dose.
Once daily, consistent timing. Very long half-life (~60 hours) means stable plasma levels even with once-daily dosing. Morning preferred.
8-12 week cycles. PCT mandatory due to significant HPG axis suppression.
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