Activin/myostatin-binding glycoprotein (research)
Follistatin
A myostatin/activin-binding protein studied for muscle hypertrophy research; systemic use carries substantial theoretical risks.
- Evidence:
- Insufficient evidence summarized
- Status:
- Research-stage
- Reviewed:
- 2026-08-03
Also known as: FST-344, Follistatin
What is Follistatin?
A myostatin/activin-binding protein studied for muscle hypertrophy research; systemic use carries substantial theoretical risks.
This profile is educational. It organizes publicly discussed research context for Follistatin and related naming aliases — it is not a treatment guide.
Proposed mechanism
Binds and neutralizes myostatin and related TGF-β superfamily ligands, removing a brake on muscle growth in animal models.
Mechanism language on PepGuide describes how researchers discuss pathways. Proposed mechanisms can change as evidence evolves.
Current research notes
Human evidence grade: Insufficient evidence summarized
Preclinical evidence grade: Moderate human evidence
Follistatin gene therapy and protein research show strong anabolic signals in animals. Human therapeutic development is cautious due to safety and off-target concerns. Research-chemical “Follistatin 344” products lack drug-grade evidence.
Key uncertainties
- Safe systemic exposure windows in humans
Research areas being studied
- Muscle biology
- Myostatin pathway
- Cachexia research
Being studied for a topic is not the same as proven benefit in that topic. Prefer primary literature for study design, endpoints, and limitations.
Safety & side-effect notes
Reported or discussed adverse effects
- Insufficient systematic human data for research vials
Additional risks & considerations
- Off-target growth-factor effects
- Unknown human safety for research products
Regulatory status
Research-stage
Regulatory framing here is educational and can lag policy changes. Check official sources for current status.
Frequently asked questions
What is Follistatin?
A myostatin/activin-binding protein studied for muscle hypertrophy research; systemic use carries substantial theoretical risks.
How does Follistatin work (proposed mechanism)?
Binds and neutralizes myostatin and related TGF-β superfamily ligands, removing a brake on muscle growth in animal models.
What is Follistatin being researched for?
Follistatin has been discussed in research contexts including: Muscle biology, Myostatin pathway, Cachexia research.
What does current evidence say about Follistatin?
Insufficient evidence summarized. Follistatin gene therapy and protein research show strong anabolic signals in animals. Human therapeutic development is cautious due to safety and off-target concerns. Research-chemical “Follistatin 344” products lack drug-grade evidence.
What safety considerations are noted for Follistatin?
Reported or discussed considerations include: Insufficient systematic human data for research vials; Off-target growth-factor effects; Unknown human safety for research products. This is educational information, not medical advice.
References & sources
- Haidet AM et al. (2008). Follistatin gene delivery and muscle hypertrophy — Proc Natl Acad Sci USA. Evidence type: animal.
Prefer interactive tools? Open the PepGuide library entry for Follistatin or ask PepGuide AI.
Educational and research information only. PepGuide does not sell or prescribe peptides, diagnose conditions, or provide personalized medical advice. Evidence summaries may include early-stage, animal, or limited human research — none of that is a substitute for primary literature or clinician guidance.