Follistatin 344 vs Tesamorelin
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 profileTesamorelin
Tesamorelin is an FDA-approved synthetic analog of growth hormone-releasing hormone (GHRH). Approved in 2010 as Egrifta, it is the only GHRH peptide with an approved clinical indication — reduction of excess visceral abdominal fat in people with HIV-associated lipodystrophy. It has the most robust human trial evidence of any growth hormone secretagogue, including dedicated studies on visceral fat and liver fat.
Full profile| Follistatin 344 | Tesamorelin | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | FST-344, Follistatin isoform 344, FST | Egrifta, Egrifta SV, TH9507, GHRH analog |
| Evidence | Research-stage | FDA-approved |
| Dosing range | 50mcg–200mcg mcg, Once daily or every other day for 10–30 day cycles | 1.28mg–2mg mg, once daily (subcutaneous) |
| Administration | Subcutaneous injection, Intramuscular injection (into target muscle — local effect hypothesis) | Subcutaneous injection (abdomen, with site rotation) |
| 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 reactions (erythema, pruritus), Peripheral edema, Arthralgia (joint pain), Myalgia |
| Cited sources | 3 references | 5 references |
Key differences
- Evidence level differs: Follistatin 344 is research-stage, while Tesamorelin is fda-approved.
- Administration: Follistatin 344 — Subcutaneous injection, Intramuscular injection (into target muscle — local effect hypothesis); Tesamorelin — Subcutaneous injection (abdomen, with site rotation).
- Dosing units differ: Follistatin 344 is dosed in mcg, Tesamorelin in mg — they operate at different scales.
- Frequency: Follistatin 344 is typically Once daily or every other day for 10–30 day cycles; Tesamorelin is once daily (subcutaneous).
- Research depth: this profile cites 3 sources for Follistatin 344 vs 5 for Tesamorelin.
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.
Tesamorelin
Tesamorelin stimulates pulsatile growth hormone (GH) release from the pituitary, raising serum IGF-1 and preferentially reducing visceral adipose tissue (VAT). FDA-registration trials (Falutz et al., NEJM 2007; JAIDS 2010) showed ~15% VAT reduction versus placebo over 26 weeks. Later randomized trials (Stanley et al., JAMA 2014; Lancet HIV 2019) extended the evidence to liver fat, showing meaningful reductions in hepatic fat fraction and attenuated fibrosis progression in HIV-associated NAFLD.
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.