Head to head
Bimagrumab against Enobosarm
Two approaches to keeping muscle during GLP-1 weight loss, an activin receptor antibody and a selective androgen receptor modulator sold on the grey market as ostarine. Both report lean mass effects and neither has shown that preserving lean mass on a scan changes how a person functions.
Column A
BimagrumabBimagrumab (anti-activin receptor antibody)
A muscle-preserving antibody that blocks activin receptors to reduce fat while increasing lean mass, being studied alongside GLP-1 drugs.
Column B
EnobosarmEnobosarm (ostarine, GTx-024, MK-2866)
The selective androgen receptor modulator known on the gray market as ostarine, now in formal trials where 3 mg cut lean-mass loss on semaglutide by 71% in adults over 60.
Side by side, on the facts we can check
| Attribute | Bimagrumab | Enobosarm |
|---|---|---|
| Category | Metabolic | Muscle & Performance |
| FDA status | Investigational for obesity / body composition; Phase 2 BELIEVE published 2026 | Investigational; not approved for any use. Unapproved SARM products are illegal to sell as supplements. |
| Half-life | Weeks (antibody) | ~24 hours (once-daily oral) |
| Molecular weight | About 150 kDa (IgG1 monoclonal antibody; KEGG lists the full heavy and light chain sequences but no mass) | 389.3 Da |
| Mechanism | Blocks activin type II receptors, neutralizing myostatin and activin signaling to build muscle and reduce fat mass. | Tissue-selective androgen receptor agonism that promotes muscle protein synthesis with less androgenic effect on prostate and skin than testosterone. |
| Human studies cited | 2 | 3 |
| Legal status, US | Investigational, not approved | Investigational; SARMs are not legal dietary ingredients and are on the WADA prohibited list |
Frequently asked questions
What is the difference between Bimagrumab and Enobosarm?
Bimagrumab: A muscle-preserving antibody that blocks activin receptors to reduce fat while increasing lean mass, being studied alongside GLP-1 drugs. Enobosarm: The selective androgen receptor modulator known on the gray market as ostarine, now in formal trials where 3 mg cut lean-mass loss on semaglutide by 71% in adults over 60.
Which has stronger research evidence, Bimagrumab or Enobosarm?
This database does not grade compounds. It counts what was run in people: 2 of the 2 studies cited on the Bimagrumab profile were human work, against 3 of 3 for Enobosarm. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Bimagrumab and Enobosarm FDA-approved?
Bimagrumab: Investigational for obesity / body composition; Phase 2 BELIEVE published 2026. Enobosarm: Investigational; not approved for any use. Unapproved SARM products are illegal to sell as supplements..
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.