ACE-031 vs PEG-MGF
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
ACE-031
Soluble form of activin type IIB receptor (ActRIIB-Fc fusion protein) that acts as a myostatin and activin trap. Blocks the primary signals that limit muscle growth by sequestering myostatin, activin, and related ligands before they reach cell surface receptors. Phase 2 trials in Duchenne muscular dystrophy demonstrated significant lean mass increases.
Full profilePEG-MGF
PEG-MGF is Mechano Growth Factor (MGF) conjugated to a polyethylene glycol (PEG) polymer chain. The PEGylation dramatically extends the half-life from ~5 minutes (native MGF) to approximately 24–72 hours, allowing less frequent dosing and systemic distribution rather than purely local action. This trade-off — longer duration vs localized intensity — makes PEG-MGF a different tool than native MGF, better suited for systemic muscle recovery support and convenience-focused protocols.
Full profile| ACE-031 | PEG-MGF | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | ACVR2B-Fc, ActRIIB-Fc fusion protein | PEGylated Mechano Growth Factor, Polyethylene Glycol-MGF, Long-acting MGF |
| Evidence | Investigational (in trials) | Preclinical only |
| Dosing range | 0.3mg/kg–3mg/kg mg/kg, every 2–4 weeks (subcutaneous injection) | 100mcg–400mcg mcg, 2x weekly (Monday/Thursday or similar split) |
| Administration | Subcutaneous injection | Subcutaneous injection (preferred for systemic distribution), Intramuscular injection |
| Key side effects | Nosebleeds (epistaxis — most common reported AE), Telangiectasia (visible small blood vessel dilation), Gum bleeding, Elevated hemoglobin | Hypoglycemia (less pronounced than IGF-1 DES, more than native MGF due to systemic distribution), Generalized fatigue on injection days, PEG accumulation concern with very high doses over long periods (theoretical — not established at research doses), Localized injection site swelling |
| Cited sources | 2 references | 2 references |
Key differences
- Evidence level differs: ACE-031 is investigational (in trials), while PEG-MGF is preclinical only.
- Administration: ACE-031 — Subcutaneous injection; PEG-MGF — Subcutaneous injection (preferred for systemic distribution), Intramuscular injection.
- Dosing units differ: ACE-031 is dosed in mg/kg, PEG-MGF in mcg — they operate at different scales.
- Frequency: ACE-031 is typically every 2–4 weeks (subcutaneous injection); PEG-MGF is 2x weekly (Monday/Thursday or similar split).
How each works
ACE-031
ACE-031 functions as a decoy receptor, binding myostatin, activin A/B, GDF-11, and BMP-9 in circulation before they can activate cellular ActRIIB receptors. In the Duchenne muscular dystrophy Phase 2 trial, ACE-031 produced meaningful lean body mass increases but was halted due to vascular side effects (epistaxis, telangiectasia) requiring dose and safety optimization.
PEG-MGF
PEGylation is a validated pharmaceutical strategy for extending peptide half-life (used in Pegasys/interferon, Somavert/pegvisomant, and others). The PEG chain shields the MGF peptide from proteolytic degradation and slows renal clearance. Research in rodent models confirms PEG-MGF preserves the biological activity of native MGF (satellite cell activation, muscle repair) with extended duration. Unlike native MGF which requires precise post-workout injection timing, PEG-MGF can be injected on a scheduled basis and still achieves systemic muscle-wide satellite cell effects.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.