ACE-031 vs Exemestane
Emerging vs FDA Approved
synergistic Mechanism-based · 46% Exemestane supports hormonal recovery from suppression caused by ACE-031. Standard protocol — begin PCT after the suppressive compound has cleared based on its half-life.
Molecular Data
ACE-031 Exemestane
Weight — 296.40 Da
Half-life 12-15 days ~24 hours
Type Soluble activin receptor type IIB-Fc fusion protein Steroidal aromatase inhibitor (irreversible, suicide inhibitor)
Key Benefits
ACE-031
01 Significant lean mass increases (up to 1.7% in 29 days) observed in Phase 1 trials
02 Simultaneous reduction in fat mass alongside muscle gains
03 Long half-life (12-15 days) allows infrequent dosing
04 Broad TGF-beta ligand neutralization for robust anti-catabolic effects
05 Dose-dependent increases in thigh muscle volume confirmed by MRI
Exemestane
01 Irreversible aromatase inactivation eliminates estrogen rebound upon discontinuation
02 Steroidal structure with mild androgenic activity may offset some low-estrogen side effects
03 Potent estrogen suppression (85-95% reduction in estradiol at full dose)
04 Compatible with tamoxifen (unlike anastrozole, no pharmacokinetic interference)
05 Prevents gynecomastia during testosterone or aromatizable steroid cycles
06 Reduces estrogen-driven water retention, bloating, and blood pressure elevation
07 Oral dosing with once-daily or less frequent administration for cycle support
Dosing Protocols
ACE-031
0.5-3 mg/kg IV every 2 weeks (clinical research doses only) / Every 2 weeks
Phase 1 Research Protocol (Healthy Volunteers) 0.1-3 mg/kg Single IV dose
Phase 2 Research Protocol (DMD) 0.5-2.5 mg/kg Every 2 weeks
Exemestane
12.5mg EOD or 25mg E3D (estrogen management) / Every other day to every 3 days (cycle support); daily (breast cancer)
Side Effects
ACE-031
Nosebleeds (epistaxis) - most frequently reported adverse event
Gum bleeding
Telangiectasia (dilated small blood vessels visible on skin)
Skin erythema (redness)
Minor injection site reactions
Exemestane
Joint pain and stiffness (generally less severe than with anastrozole due to mild androgenic activity)
Fatigue and general malaise
Hot flashes or flushing
Mood changes (irritability, flat affect, low mood)
Headache
Increased sweating
Contraindications
NEVER approved for human use - clinical development discontinued
History of bleeding disorders or vascular malformations
Concurrent anticoagulant or antiplatelet therapy
Known hypersensitivity to Fc fusion proteins
Pregnancy or breastfeeding
Known hypersensitivity to exemestane or any excipients
Premenopausal women (not indicated and potentially harmful to reproductive function)
Pregnancy or breastfeeding (teratogenic risk)
Severe hepatic impairment
Pre-existing severe osteoporosis or high fracture risk
Concurrent use with other aromatase inhibitors (anastrozole, letrozole)
Research Evidence
ACE-031 Exemestane
Status Emerging FDA Approved
References 4 studies 5 studies
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.