FS315 vs ACE-031
Head-to-head comparison of FS315 (Follistatin-315 (FS315)) and ACE-031 (ACE-031 (soluble activin receptor type IIB-Fc)) — benefits, dosing, side effects, research data, and where to buy.
| Property | FS315 | ACE-031 |
|---|---|---|
| Category | Muscle & Performance | Muscle & Performance |
| Full Name | Follistatin-315 (FS315) | ACE-031 (soluble activin receptor type IIB-Fc) |
| Molecular Weight | ~40 kDa | ~95 kDa |
| Half-Life | N/A; depends on construct/delivery | Days to weeks |
| Amino Acids | 315 | N/A |
| Typical Dose | Research-only; no standardized human dose | 0.1-3 mg/kg in early studies |
| Route | Intramuscular / research expression systems | Subcutaneous |
| Purity | ≥98% | ≥98% |
| Studies Count | 95 | 75 |
| Research Status | Pre-clinical | Clinical |
FS315 Benefits
- ✓activin neutralization
- ✓muscle growth signaling
- ✓anti-catabolic support
- ✓tissue repair modulation
ACE-031 Benefits
- ✓myostatin/activin neutralization
- ✓lean mass gain
- ✓muscle function support
- ✓anti-catabolic effect
FS315 Dosing
Research-only recombinant/protein-expression studies|no standardized clinical dose|route varies by platform
ACE-031 Dosing
Clinical studies used single or repeated SC doses|dose escalation in mg/kg|monitoring for edema/bleeding
FS315 Side Effects
- ⚠off-target endocrine effects
- ⚠immune response risk
- ⚠fluid balance changes
ACE-031 Side Effects
- ⚠telangiectasia/vascular effects
- ⚠epistaxis
- ⚠headache/edema
Research Overview
FS315
Follistatin-315 is a key reference isoform in studies of muscle anabolism and reproductive/endocrine biology. In muscle research, it is relevant because it suppresses activin and can indirectly blunt myostatin pathway output.
ACE-031
ACE-031 produced increases in lean mass in early studies, but development was curtailed after safety concerns and variable efficacy. Its literature remains important because it validated activin receptor blockade as a muscle-building strategy.
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