On this page
This entry or formulation may be investigational and may not correspond to an FDA-approved product; safety and efficacy may not have been established. Kairo lists it for identification and record-keeping only.
Overview
Product & regulatory status
A gene-therapy study does not validate a supplied follistatin protein preparation.
Protein isoforms
NCBI describes alternatively spliced FST precursors including FST344 and FST317. An isoform label is a molecular distinction, not a clinical result. [1]
What the evidence shows
What the human trial actually tested
A phase 1/2a study treated six people with Becker muscular dystrophy using an AAV vector carrying FS344. Four improved on the walking test and two did not; there was no randomized placebo group. [2]
Why delivery changes the interpretation
The intervention delivered a gene to muscle so cells could produce a protein. It was not a trial of repeated injected follistatin protein or a study in healthy athletes. [2]
What remains unknown
This small study cannot establish general muscle-enhancement benefit, long-term safety in healthy people, or equivalence of commercially offered protein products.
Safety
Small studies cannot exclude uncommon harm
No adverse effects were reported in this six-person trial, but that does not establish safety for another delivery method or population. [2]
Gene therapy versus protein vial
AAV-mediated FS344 expression and a vial labeled Follistatin 344 are different interventions. The study does not establish their equivalence. [2]
Understanding product quality
Compounded drugs are not FDA-approved finished products. Poor preparation can cause contamination or incorrect strength. A catalog entry or a research paper is not a quality assessment of your product. [3]
When to seek urgent help
Severe allergic symptoms such as trouble breathing, throat or tongue swelling, or fainting need immediate help. Call 911 or your local emergency number. This is general emergency information, not a complete list of risks for this compound. [4]
A starting point for discussion
This is not a complete list of adverse effects or interactions. Your health history, other medicines, and the exact formulation matter. Missing safety data is not evidence of safety.
Common questions
What does 344 identify?
It identifies a precursor isoform described in gene biology. It does not indicate purity, activity, or a clinically established amount.
Questions for your clinician
Does the evidence match my condition and this exact product? What risks or interactions matter for me? How would we assess whether it is helping?
Sources
- FST follistatin — Homo sapiensNCBI Gene · Gene identity and isoforms
- A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy2015 · Primary research · PubMed
- Compounding and the FDA: Questions and AnswersFDA · product quality and regulation
- AnaphylaxisMedlinePlus · recognizing an emergency
Educational information, not a recommendation to use a compound. Kairo does not give dosing advice. Review decisions with a licensed healthcare professional.