Folistatina (FST): what it is and what the evidence says
A protein studied for its relationship with myostatin regulation and signals associated with muscle development.
Last reviewed: August 16, 2026 · How we verify this
The ground it plays on
Tissue repair happens in phases, not all at once: an initial inflammation that is actually useful, the building of new tissue, and then its remodelling, which can take months. Compounds studied in this area relate to one of those phases. None of them replaces rest or rehabilitation, and that is precisely the most common mistake people make when reading about them.
What it is studied for
Muscle development, composition.
There is a distinction that almost always gets lost. A compound being studied for something is not the same as achieving it. And even where it works in a dish or in a mouse, that says little about whether it works in a person or whether the benefit is worth the risk. The section below therefore carries more weight than everything above it.
What the human evidence says
The only thing tested in people is gene therapy injected directly into muscle (phase 1/2a trials in Becker muscular dystrophy and in inclusion body myositis), with very small samples and no randomized control group. There is no clinical trial of injectable follistatin as a peptide.
The limitation that matters most
The spectacular hypertrophy that gets cited comes from transgenic mice and local gene transfer, not from follistatin injections; on top of that it blocks activins involved in the reproductive, hepatic and inflammatory axes, and the human meta-analysis shows modest and heterogeneous changes.
Regulatory status
Not approved. The only thing tested in people was gene therapy in phase 1/2a trials. Banned in sport by WADA.
Status can change and varies by country. Always verify the rules in force where you live before drawing conclusions.
Cautions and context
Developing research; long-term effects and safety not well characterized.
Only within a professional framework; not a self-managed strategy.
What this page cannot give you
A reference page can take you this far. You know what Folistatina (FST) is and where its research stands, which already puts you ahead of most readers. Four questions remain that no encyclopedia can answer for you, because the answers depend on your own situation:
- What would you measure beforehand, so that later you could tell whether anything actually changed?
- What would you watch along the way, and how consistently?
- What would you ask a professional, and in how much detail, so you do not walk out with a textbook answer?
- What would make you stop?
That is what the course is for
PeptiXtreme is ${CIF.LECCIONES} lessons that hand out no numbers. Each one ends with your starting point, what to watch along the way, the specific questions you take to a professional and the signals that mean stop. It includes per-module exams, a diploma with a verifiable folio, a record to track how you progress, and a human advisor you can actually write to.
See the course → Or measure your judgment, freeReferences
Every entry links to its record on PubMed, the US National Library of Medicine database. Open them and check. We would rather have a reader who verifies than one who takes our word for it.
- Follistatin Gene Therapy for Sporadic Inclusion Body Myositis Improves Functional Outcomeshuman Mol Ther · 2017 · PMID 28279643 →
- A phase 1/2a follistatin gene therapy trial for becker muscular dystrophyhuman Mol Ther · 2015 · PMID 25322757 →
- The effects of resistance training on myostatin and follistatin in adults: A systematic review and meta-analysis Physiol Behav · 2023 · PMID 37328021 →
- Regulation of myostatin activity and muscle growthpreclinical Proc Natl Acad Sci U S A · 2001 · PMID 11459935 →
- Follistatin induces muscle hypertrophy through satellite cell proliferation and inhibition of both myostatin and activinpreclinical Am J Physiol Endocrinol Metab · 2009 · PMID 19435857 →
- Follistatin-mediated skeletal muscle hypertrophy is regulated by Smad3 and mTOR independently of myostatinpreclinical J Cell Biol · 2012 · PMID 22711699 →
- Transgenic expression of a myostatin inhibitor derived from follistatin increases skeletal muscle mass and ameliorates dystrophic pathology in mdx micepreclinical FASEB J · 2008 · PMID 17893249 →
- Regulation of muscle mass by follistatin and activinsreview Mol Endocrinol · 2010 · PMID 20810712 →
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Frequently asked questions
What is Folistatina (FST)?
A protein studied for its relationship with myostatin regulation and signals associated with muscle development. It is studied within the area of regenerative.
Is there human evidence for Folistatina (FST)?
The only thing tested in people is gene therapy injected directly into muscle (phase 1/2a trials in Becker muscular dystrophy and in inclusion body myositis), with very small samples and no randomized control group. There is no clinical trial of injectable follistatin as a peptide.
Is it approved by any health agency?
Not approved. The only thing tested in people was gene therapy in phase 1/2a trials. Banned in sport by WADA.
What is the dose of Folistatina (FST)?
We do not publish dosages. This is not an oversight. No single figure works for everyone: the regimen depends on a person's medical history, on whatever medication they already take, and on the goal they are chasing, which is something a professional weighs with the case in front of them. What you can build is the ability to walk into that appointment knowing what to ask.
Where can I learn to evaluate this properly?
This page tells you what Folistatina (FST) is and what the evidence says. The PeptiXtreme course teaches the other half: what you would measure before considering anything, what you would watch, the specific questions you would take to a professional and when you would stop.