Ostarine (MK-2866) and LGD-4033 (Ligandrol) are the two SARMs with the most robust published human trial datasets. Despite operating through the same basic mechanism, they differ significantly in potency, suppression characteristics, and the depth of their clinical research programmes.
The most significant practical distinction between the two compounds is potency. In the GTx Phase II trials, Ostarine produced statistically significant lean mass gains at 1–3 mg/day. In the Basaria 2013 LGD-4033 trial, comparable or greater lean mass effects were observed at 1 mg/day — suggesting LGD-4033 is meaningfully more potent per milligram.
Typical research doses reflect this: Ostarine protocols commonly use 10–25 mg/day; LGD-4033 protocols typically use 5–10 mg/day to achieve comparable or greater effects. For researchers requiring less aggressive AR activation, Ostarine's milder potency may be an advantage in certain protocol designs.
Testosterone suppression is dose-dependent for both compounds. The published data indicates:
The deeper suppression of LGD-4033 at comparable lean mass-effective doses is an important consideration in research protocol design and post-cycle support planning.
Ostarine has the most extensive published human data of any SARM, having progressed to Phase III oncology trials. LGD-4033 has the most rigorous controlled human pharmacokinetic data from healthy volunteers (Basaria 2013). Both are considerably better characterised in human research than RAD-140, YK-11, S-23, or LGD-3033.
| Parameter | Ostarine (MK-2866) | LGD-4033 |
|---|---|---|
| Potency (relative) | Mild–moderate | Moderate–high |
| Typical research dose | 10–25 mg/day | 5–10 mg/day |
| Half-life | ~24 hours | ~24–36 hours |
| Suppression (typical doses) | Mild–moderate | Moderate–significant |
| Human phase trial data | Phase II/III (cachexia) | Phase I (healthy men) |
| Aromatisation | None | None |
Ostarine's well-characterised human safety profile, mild potency, and the most extensive published clinical data of any SARM make it a logical starting compound for researchers building a SARM research programme. Its lower potency provides more granular dose-response data and its recovery characteristics are well-documented.
At lean mass-effective doses, yes. The Basaria 2013 data shows approximately 50% testosterone suppression at 1 mg/day LGD-4033 over 21 days. Ostarine at comparable lean mass doses (3 mg/day) produces milder suppression. At higher research doses (10–25 mg LGD-4033), suppression is proportionally greater.
