Overview
ACE-031 is an investigational fusion protein designed as a soluble decoy receptor to block myostatin and related muscle-inhibiting proteins.
What problem it targets: It was engineered to address severe muscle wasting conditions and neuromuscular diseases by removing the body's natural biological limiters on muscle growth.
What It Does
• Traps myostatin before it hits muscle receptors: ACE-031 binds circulating myostatin (GDF-8) and activins, preventing them from attaching to ActRIIB receptors that signal muscles to stop growing.
• Drives substantial muscle hypertrophy: By releasing the molecular "brakes" on skeletal muscle, it triggers rapid increases in lean muscle mass and physical strength in experimental models.
• Cross-reacts with vascular proteins: Because it also binds BMP9 (a growth factor required for blood vessel stability), clinical trials observed micro-bleeding issues such as nosebleeds and skin vessel dilation.
• Realistic expectations: Due to vascular side effects, its clinical development was discontinued. It serves as a potent research model for myostatin inhibition rather than a practical or safe long-term muscle builder.
Reconstitution
| Vial size | BAC water / Solvent | Concentration |
|---|
| 1 mg | + 1 mL | 1 mg/mL |
Handling & Stacking
Injection site
SubQ if used. Rotate.
Storage
Freeze-dried: -4°F. Reconstituted: 36–46°F, best used within ~2–4 weeks (structure-based estimate), kept cold; an Fc-fusion that aggregates without stabilisers, so use it sooner.
Side effects
Nosebleeds, gum bleeding, skin telangiectasias (dilated vessels), headache. Vascular bleeding is the signature risk.
What to expect
- Increased muscle mass in principle, but with a real bleeding-risk profile that ended its clinical development.
- Risk/benefit is unfavorable for physique use.
- Supply math Not applicable, no validated safe human dose.
- Research compound only.
Pairs well with
Not recommended for stacking given the bleeding-risk profile
Avoid
Bleeding disorders. Anticoagulant/antiplatelet use. Vascular abnormalities. Pregnancy. Honestly: avoid pending a safe human protocol
Safety & Patient Education
Contraindications
Any bleeding disorder or anticoagulant/antiplatelet therapy Known vascular malformations / telangiectasia Pregnancy and lactation Active malignancy
Warnings
Mechanism-based vascular bleeding (BMP9 inhibition), ended the clinical program No safe, validated human dosing for physique use Activin/myostatin pathway inhibition has broad off-target effects Not an approved drug
Drug interactions
Anticoagulants / antiplatelets / NSAIDs: compounded bleeding risk, avoid Other growth-promoting agents: unknown combined risk
Labs
CBC and bleeding assessment if used at all Watch for epistaxis, gum bleeding, new skin vascular lesions
Stop criteria
Any abnormal bleeding (nose, gums, skin) New telangiectasias Any sign of internal bleeding
Patient education
This compound’s clinical trial was stopped early for bleeding, that is the headline There is no established safe physique dose; included for completeness, not endorsement Do not combine with anything affecting bleeding Stop immediately for any abnormal bleeding
References
PubMed · clinicaltrials.gov · researchdosing
