PeptiDex
Peptide Research Index
Research-backed
Peptide Research Index
⚠️ Educational only · Not medical advice · Consult a doctor · Most peptides are research-only / not FDA-approved for human use
⚠️ Educational only · Not medical advice · Consult a doctor · Most peptides are research-only / not FDA-approved for human use
Also: FS-344
💪Myostatin InhibitorBlocks myostatin (the body's muscle growth limiter) and activin, allowing enhanced muscle development and regeneration beyond normal physiological limits.
Rodino-Klapac et al. (Mol. Ther.): AAV-delivered follistatin 344 increases muscle mass and fiber diameter across multiple animal species without adverse reproductive or endocrine effects.
preclinicalKalista et al.: Review of follistatin's role as primary endogenous myostatin antagonist and its therapeutic potential for muscular dystrophies and sarcopenia.
preclinicalMendell et al. (Mol. Ther.): Phase I clinical trial of AAV1-follistatin gene transfer in Becker muscular dystrophy patients shows improved 6-minute walk test with no adverse effects.
moderateResearch demonstrating follistatin's broader metabolic role in adipocyte browning, energy expenditure, and metabolic health beyond muscle hypertrophy.
preclinicalResearch-only. Potent effects potential for unregulated growth. Limited human safety data. Phase I gene therapy trials show safety.
⚠️ For educational purposes only. Not medical advice. Consult a healthcare professional before using any peptide.
Very short cycles. 100mcg/day common. Acts via myostatin/activin inhibition effects compound over days.
Last updated: 2026-01 · Laws change frequently. Verify current status in your jurisdiction.
Weeks 2-4
Initial myostatin inhibition; muscle fullness and pumps
Month 2-3
Measurable lean mass increase; strength gains
Long-term
Very limited long-term human data; Phase I gene therapy shows safety
| Side Effect | Incidence | Severity |
|---|---|---|
Limited human safety data | Investigational only | mild |
Injection site reaction | ~5% of users | mild |
Theoretical cancer promotion Myostatin inhibition could allow unregulated cell growth | Mechanism-based concern | rare |
Incidence rates sourced from published clinical trial data where available; otherwise based on community research observations.
Maximize lean muscle gain through GH optimization, growth factor signaling, and myostatin inhibition
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