ACE-031 vs 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 profileMGF
MGF (Mechano Growth Factor) is a splice variant of IGF-1 produced locally in muscle tissue in response to mechanical loading (exercise, especially eccentric loading). Unlike circulating IGF-1 which is produced primarily by the liver, MGF is generated within the muscle itself and acts locally to activate satellite cells (muscle stem cells) — the cells responsible for muscle repair, growth, and adaptation. It is considered the primary local anabolic signal generated by resistance training.
Full profile| ACE-031 | MGF | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | ACVR2B-Fc, ActRIIB-Fc fusion protein | Mechano Growth Factor, IGF-1Ec, Insulin-like Growth Factor splice variant |
| Evidence | Investigational (in trials) | Preclinical only |
| Dosing range | 0.3mg/kg–3mg/kg mg/kg, every 2–4 weeks (subcutaneous injection) | 100mcg–300mcg mcg, Post-workout (within 30–60 minutes of training), 3–4x weekly |
| Administration | Subcutaneous injection | Intramuscular injection (into worked muscle — critical for local effect), Subcutaneous injection (produces more systemic distribution) |
| Key side effects | Nosebleeds (epistaxis — most common reported AE), Telangiectasia (visible small blood vessel dilation), Gum bleeding, Elevated hemoglobin | Localized muscle swelling at injection site (normal response), Hypoglycemia (less pronounced than IGF-1 DES but present), Very short half-life means side effects are brief, Potential overuse injury if post-workout injection is used consistently without adequate recovery |
| Cited sources | 2 references | 3 references |
Key differences
- Evidence level differs: ACE-031 is investigational (in trials), while MGF is preclinical only.
- Administration: ACE-031 — Subcutaneous injection; MGF — Intramuscular injection (into worked muscle — critical for local effect), Subcutaneous injection (produces more systemic distribution).
- Dosing units differ: ACE-031 is dosed in mg/kg, MGF in mcg — they operate at different scales.
- Frequency: ACE-031 is typically every 2–4 weeks (subcutaneous injection); MGF is Post-workout (within 30–60 minutes of training), 3–4x weekly.
- Research depth: this profile cites 2 sources for ACE-031 vs 3 for MGF.
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.
MGF
MGF is encoded by the IGF-1 gene but produced via alternative splicing that generates a unique 49-amino acid C-terminal E-peptide (Ec peptide). The Ec peptide has distinct biological activity from the IGF-1 domain — it directly activates satellite cell proliferation through a receptor pathway separate from the standard IGF-1R. Studies in rodents show that local MGF injection produces significant muscle hypertrophy in the injected limb without systemic IGF-1 elevation. MGF expression spikes within 30 minutes of resistance exercise and declines over 24–48 hours — aligning precisely with the post-exercise anabolic window.
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.