Peps
What is Follistatin 344?
Follistatin 344 refers to a follistatin precursor isoform. A frequently cited human study delivered an FS344 gene construct using a viral vector; it did not test injections of a supplier’s follistatin protein.
Biological role or research focus
Myostatin-pathway and muscular-dystrophy research.
The lack of a concurrent control limits causal interpretation. Gene-delivery outcomes cannot be transferred to a protein vial, and six participants cannot exclude uncommon harms.
Role reference: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Names you may encounter
FS344 · FST344 · FLGR242
Search terms can include brands, combinations, or historical names. They are not automatic product equivalents.
- Class / identity
- Follistatin precursor isoform used in gene-therapy research
- Research focus
- Myostatin-pathway and muscular-dystrophy research
- Featured evidence
- Related intervention · Human uncontrolled gene-therapy study
- Source check
- October 4, 2026
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Biology & proposed mechanism
Follistatin antagonizes members of the activin/myostatin signaling system. Expressing a gene construct in muscle is a different intervention from administering a purified protein preparation.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Research context & identity
The featured study concerns a proof-of-principle muscular-dystrophy intervention. It does not validate bodybuilding products labeled Follistatin 344.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
What does the evidence show?
Selected published evidence, with the population, findings, and limits kept together. These original summaries draw on publication abstracts; they are not a systematic review.
Related intervention · Human uncontrolled gene-therapy study · 2015
FS344 gene therapy in Becker muscular dystrophy
What did this publication test, and what did it find?
- Population / model
- Six men with Becker muscular dystrophy.
- Study design
- Uncontrolled phase 1/2a study of intramuscular AAV1.CMV.FS344 gene delivery.
- Main finding
- Four participants improved their six-minute-walk distance, while two showed no improvement. No adverse effects were reported in this small study.
- Limits & context
- The lack of a concurrent control limits causal interpretation. Gene-delivery outcomes cannot be transferred to a protein vial, and six participants cannot exclude uncommon harms.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Human retrospective case series · 2020
Follistatin-344 listings · eye-harm signal
What safety signal has been reported after self-administration?
- Population / model
- 11 male bodybuilding athletes seen at one clinic with reduced vision after injections labeled follistatin-344.
- Study design
- Retrospective clinical records and retinal imaging; no comparison group.
- Main finding
- Central serous chorioretinopathy was identified. Fluid resolved after an average 2.3 months in eight single-exposure cases; three multiple-exposure cases had recurrence.
- How to read it
- This is an association and a reason to investigate, not a controlled estimate of causal risk.
- Limits & context
- Referral selection, lack of a denominator, possible confounding, and uncertain product identity prevent estimating incidence or proving causation. It supplies no evidence of muscle-building efficacy.
Analytical product study · 2019
Follistatin-344 · product identity testing
Did the tested products contain what their labels claimed?
- Population / model
- 17 black-market products sold as follistatin formulations.
- Study design
- Protein detection methods using purification, electrophoresis, and immunoblotting.
- Main finding
- Nine products contained follistatin; others included growth-promoting peptides. The nine positive products contained His-tagged FS344 with substantial oligomers.
- How to read it
- A supplier label is not confirmation of protein identity, purity, or clinical equivalence.
- Limits & context
- This small historical sample is not a current supplier ranking or market-wide prevalence estimate. Detection does not demonstrate safety or effectiveness. A linked published erratum should also be consulted.
Read the original paper for methods, adverse events, funding, and conflicts of interest. Publisher access may require a subscription.
Further reading · 2 additional publication links
Exact-name PubMed search checked 2026-10-04. These records have not been appraised. A name match can include related compounds, combinations, or other formulations; it does not establish safety or benefit.
Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. ↗
Sports medicine (Auckland, N.Z.) · 2026 Aug · Journal Article, Review
Detection of black market follistatin 344. ↗
Drug testing and analysis · 2020 Oct · Published Erratum
New editorial updates
New source discoveries
Links appear automatically. Unreviewed discoveries are not verified medical findings.
Safety & precautions
Safety & what remains unknown
A viral-vector intervention has a different safety profile from protein administration. The study does not establish a safe consumer use.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Evidence boundaries
The lack of a concurrent control limits causal interpretation. Gene-delivery outcomes cannot be transferred to a protein vial, and six participants cannot exclude uncommon harms.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
This is not a complete list of contraindications, interactions, or adverse effects. Medicine labels apply to specific products and indications; research-use listings are not interchangeable with approved medicines.
What are people discussing?
No editorial transcript note has been reviewed for this profile yet. Below are the matching video records available for exploration; title and caption matches are not verified claims.
Watch the source discussions
0 matching video records · 0 with captions indexed.
Across the full library, 30 caption files are indexed from 20,199 inventoried videos. Most transcripts remain unreviewed. Select a thumbnail or timestamp to watch inside PepsRadar. Thumbnail images load from YouTube.
No matching video has been identified in the current snapshot.
Sources & supplier listings
Listings are grouped by the vendor’s stated identity. Blends and modified derivatives are labeled separately. Inclusion is not a quality assessment or an endorsement.
FLGR242 (10mg)
BioLongevity Labs · Vendor-labeled research use only
$499.00–$19,161.60
Listed in stock · Snapshot 2026-10-04
Options may vary. Shipping and tax excluded.
Affiliate link · PepsRadar may earn a commission from purchases through this link. Affiliate disclosure.
Catalog checked 2026-10-04. Seller listings retain their stated intended use. Shops covered: BioLongevity Labs, BioLongevity Supplements, American Peptides, PSPeptides. This is not a market-wide comparison. Affiliate participation does not determine evidence or editorial coverage.
Questions worth asking
- Was the human trial an injection of Follistatin 344 protein?
- What material, population, and route were actually studied?
- The lack of a concurrent control limits causal interpretation. Gene-delivery outcomes cannot be transferred to a protein vial, and six participants cannot exclude uncommon harms.
- What adverse effects, uncertainty, and conflicts of interest does the original source report?
Frequently asked questions
Was the human trial an injection of Follistatin 344 protein?
No. It delivered an FS344 gene construct using an adeno-associated viral vector. That distinction is central to interpreting the result.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
Does the publication verify a supplier’s product?
No. The tested material and a commercial listing need separate identity and batch checks. A research-use disclaimer does not establish clinical suitability.
Source: A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. · 2015 ↗
References & editorial record
- PubMed · PMID 25322757 ↗
- Central serous chorioretinopathy associated with high-dose follistatin-344: a retrospective case series. ↗
- Detection of black market follistatin 344. ↗
Source notes checked 2026-10-04. Original PepsRadar summaries. Not reviewed by a medical professional. Topic grouping is editorial navigation, not a treatment recommendation. Video notes specify which excerpts were reviewed; no full transcripts are published.