PERFORMANCE · Injectable
Follistatin 344.
Myostatin inhibitor — unlocks muscle growth ceiling
How it works
Class & mechanism.
In short
Follistatin-344 is a research peptide that works by neutralizing myostatin, a protein the body uses to cap muscle growth. By removing that natural brake, it has produced dramatic muscle gains in animal studies. It's studied mainly as a muscle-building compound rather than for injury repair or general wellness.
Class
Glycoprotein / Myostatin Inhibitor
Mechanism
Follistatin 344 (FS-344) is the 344-amino acid isoform of follistatin, an autocrine glycoprotein that binds and neutralizes members of the TGF-β superfamily — particularly myostatin (GDF-8) and activin. By blocking myostatin, it removes a key biological brake on skeletal muscle growth. Lee & McPherron (2001, PNAS) demonstrated that follistatin overexpression produces "mighty mice" with 2–3× normal muscle mass. AAV-follistatin gene therapy in macaques produced significant muscle growth and strength gains (Rodino-Klapac, 2009). Recombinant injectable FS-344 is used off-label; no formal human PK studies for the injectable form exist.
Personalized Peptides provides DNA-driven peptide recommendations — we are not a compounding pharmacy, peptide synthesis company, or clinical provider.
Did you know
Follistatin is so powerful at building muscle that a single gene therapy injection can produce permanent muscle growth — the "mighty mice" stayed muscular for life. The challenge isn't making it work; it's controlling how much it works.
Benefits
What it does.
Myostatin inhibition — directly removes the primary biological limit on skeletal muscle hypertrophy
Significant muscle growth — animal models show 2–3× increases in muscle mass with follistatin overexpression
Strength gains — macaque AAV-follistatin studies demonstrated functional strength improvements alongside hypertrophy
Regenerative potential — preclinical data suggests enhanced muscle repair and reduced fibrosis in injury models
The science
Peer-reviewed findings.
Research supporting this compound's mechanisms and safety profile.
What this does not mean
Follistatin-344 is a research chemical. The information on this page is educational and does not constitute medical advice, diagnosis, or treatment. Follistatin-344 is not FDA-approved for building muscle, treating any condition, or any other use. This page does not recommend, endorse, or prescribe any compound for human use. Always consult a qualified healthcare provider before making health decisions. Personalized Peptides provides DNA-driven educational context and test interpretation — not clinical protocols or pharmaceutical recommendations.
Lee & McPherron (2001, PNAS) demonstrated that follistatin overexpression produces "mighty mice" with 2–3× normal muscle mass through myostatin pathway inhibition
SOURCE · Lee SJ, McPherron AC. "Regulation of myostatin activity and muscle growth." PNAS 98(16):9306-9311, 2001. PMID: 11459935
AAV-follistatin gene therapy in macaques produced significant muscle growth and strength gains in non-human primates, establishing proof-of-concept for clinical translation
SOURCE · Rodino-Klapac et al., 2009; Nationwide Children's Hospital gene therapy program
Protocol
How to use it.
Dosing
Off-label recombinant injectable: 50–200 mcg subcutaneous or intramuscular, 3–5× per week. Intramuscular injection into target muscle theorized to provide local depot effect with sustained myostatin inhibition.
Cycle
4–8 week cycles with equal rest periods. No established human cycling data — all protocols are extrapolated from animal and gene therapy studies.
Contraindications
When to skip it.
Elevated circulating follistatin is epidemiologically linked to increased type 2 diabetes risk, early death, heart failure, stroke, and CKD (Wu 2021, Nature Communications). Follistatin suppresses FSH — potential reproductive effects. No human injectable safety data. Banned by WADA for competitive athletes.
Always cleared with your concierge before protocol start.
Regulatory Context
FDA compounding status.
| FDA Status | Risk Level | Compounding | Key Date |
|---|---|---|---|
| No specific FDA action | 🟢 Stable | Gray zone — no specific enforcement | No pending dates |
Myostatin inhibitor. Not on any FDA Category 1/2/3 lists. No pending PCAC review. Research-stage compound — primarily studied in muscle-wasting conditions.
Source: FDA Federal Register, PCAC agendas, industry analyses. Educational context only — not legal advice. Review after July 23-24, 2026 PCAC meeting.
Pricing
What it costs.
Indicative range for Follistatin 344, sourced from vetted US and EU dispensing suppliers. Concierge confirms the exact figure once your match is locked.
Indicative range (USD)
Sourced through vetted dispensing partners in the United States and European Union. Concierge confirms the exact figure once your match is locked.
- 0199% purity verified, third-party tested
- 02Includes vial and reconstitution guidance
- 03Concierge supplier match included with every protocol
See Follistatin 344 pricing — and your supplier match.
Pricing is unlocked once we know who you are. Take the 3-minute quiz and we'll match you to a US or EU dispensary based on your location and protocol fit.
- Live USD price range
- US & EU supplier shortlist
- Concierge sign-off on dosing
Indicative price range: $104–$156 USD