Rankings / Metabolic Health

Bimagrumab

Metabolic Health · Activin receptor antagonist

Tier C+

Reviewed by Read Off Label · Last reviewed · How we grade

monoclonal-antibodyinvestigational
5.7 / 10
Tier C+
Ev 6 Bn 6.5 Sf 5

Bottom line

Read Off Label grades Bimagrumab as C+ (5.7/10) based on moderate evidence, moderate-high benefit magnitude, and a med-risk safety profile.

Heymsfield JAMA 2021: -20.

Studied, labeled, or reported-use context: Phase 2 trials used 10 mg/kg IV every 4 weeks — Investigational; not individualized guidance.

What the evidence says

Heymsfield JAMA 2021: -20.5% fat mass with +3.6% lean mass gain at 48 weeks. Unique profile: most weight-loss drugs (incl. GLP-1s) cost ~25-30% of weight loss as lean mass. Now owned by Lilly — actively being explored as combo with tirzepatide for body recomposition. Highlighted in 2026 obesity-pharmacotherapy reviews (Lempesis & Dalamaga, Metabol Open) as the prototype lean-mass-preservation agent. BELIEVE Phase 2b now published in Nature Medicine (Heymsfield et al. 2026, n=507): high-dose bimagrumab+semaglutide -17.8 kg vs -3.3 kg placebo at 48 wk (bimagrumab alone -9.3 kg, semaglutide 2.4 mg alone -14.2 kg), confirming added fat-specific loss with lean-mass preservation. No Phase 3 readout yet.

Mechanism

Monoclonal antibody blocks activin type II receptors — reduces myostatin/activin signaling; increases muscle mass while reducing fat mass (body recomposition effect)

Studied, labeled, or reported dose & route

Phase 2 trials used 10 mg/kg IV every 4 weeks

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

A link means the source informed this entry; it does not mean every claim on the page comes from that source. If a citation looks wrong or you want a claim re-checked, send a correction.

Common questions

What does the evidence show about Bimagrumab's effects?
Read Off Label rates the evidence for Bimagrumab as Moderate and the benefit magnitude as moderate-high, producing an overall grade of C+ (5.7/10). Heymsfield JAMA 2021: -20.
What safety findings are reported for Bimagrumab?
Bimagrumab has a med risk profile in the database. Med (minor pancreatitis signal; acne, muscle cramps) Legal status: Investigational.
What doses or routes are reported for Bimagrumab?
Phase 2 trials used 10 mg/kg IV every 4 weeks This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Bimagrumab work?
Monoclonal antibody blocks activin type II receptors — reduces myostatin/activin signaling; increases muscle mass while reducing fat mass (body recomposition effect)

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.