Follistatin 344 vs Sermorelin
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Follistatin 344
Follistatin 344 is a 344-amino acid isoform of follistatin — an endogenous glycoprotein that functions primarily as a myostatin and activin inhibitor. Myostatin (GDF-8) is the body's primary muscle growth suppressor; follistatin binds and neutralizes it with high affinity, removing this brake on muscle protein synthesis. Research and animal data show dramatic increases in muscle fiber size and strength when follistatin is elevated or myostatin is inhibited.
Full profileSermorelin
Sermorelin is a synthetic analog of the first 29 amino acids of GHRH (Growth Hormone-Releasing Hormone). It was FDA-approved for pediatric GH deficiency diagnosis and is widely used off-label in anti-aging and performance medicine. It stimulates pulsatile GH release more physiologically than exogenous GH.
Full profile| Follistatin 344 | Sermorelin | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | FST-344, Follistatin isoform 344, FST | GHRH 1-29, GRF 1-29 NH2, Geref |
| Evidence | Research-stage | FDA-approved |
| Dosing range | 50mcg–200mcg mcg, Once daily or every other day for 10–30 day cycles | 100mcg–500mcg mcg, once daily (before sleep) |
| Administration | Subcutaneous injection, Intramuscular injection (into target muscle — local effect hypothesis) | Subcutaneous injection |
| Key side effects | Potential FSH suppression (reproductive effects in females — may affect menstrual cycle), Accelerated hair follicle cycling (Wnt pathway involvement — theoretical hair loss concern at high doses), Joint discomfort with rapid muscle tissue growth, Limited long-term human safety data | Injection site redness, Headache, Flushing, Dizziness |
| Cited sources | 3 references | 1 reference |
Key differences
- Evidence level differs: Follistatin 344 is research-stage, while Sermorelin is fda-approved.
- Administration: Follistatin 344 — Subcutaneous injection, Intramuscular injection (into target muscle — local effect hypothesis); Sermorelin — Subcutaneous injection.
- Frequency: Follistatin 344 is typically Once daily or every other day for 10–30 day cycles; Sermorelin is once daily (before sleep).
- Research depth: this profile cites 3 sources for Follistatin 344 vs 1 for Sermorelin.
How each works
Follistatin 344
Follistatin's muscle effects were dramatically illustrated when mice and cattle with follistatin overexpression or myostatin knockouts developed 2–3x normal muscle mass. Human follistatin gene therapy trials (AAV-mediated) are ongoing for Becker Muscular Dystrophy, showing sustained myostatin inhibition and improved muscle function over years from a single injection. Follistatin also inhibits activin A and B (involved in muscle wasting during illness), FSH secretion (reproductive effects), and inflammatory cytokines. The 344 isoform has an extended heparin-binding domain that increases tissue retention compared to the shorter FST-288 isoform.
Sermorelin
Sermorelin works by binding pituitary GHRH receptors to stimulate GH secretion within the body's natural feedback loop. Unlike synthetic GH, it does not suppress endogenous production. Clinical studies show improved body composition, sleep quality, and IGF-1 levels in GH-deficient adults. Its short half-life (~10 min) means it requires daily dosing.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.