Peptide Academy · Growth

Follistatin-315

Also known as FST-315

Educational research summary, not medical advice. Many compounds here are not approved for human use. Talk to a licensed clinician before making any health decision.

The Peptide Academy is free to read. Members also get the research protocols for Follistatin-315, dose and vial tracking, and an AI Advisor with cited sources. Try it all free for 7 days, no card needed.

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What is Follistatin-315?

The circulating splice isoform of follistatin, a myostatin/activin-binding protein studied for muscle growth.

How it works

Binds and neutralizes myostatin and activins, removing a key brake on muscle hypertrophy.

Published research

Gene-therapy follistatin expression produced large muscle gains in animal models
Human FST gene therapy trial (DMD/BMD) reported functional benefit

Cautions

Reproductive-axis effects (FST binds activin) are a concern; WADA-relevant.

Side effects & fixes

Common side effects

—Human side-effect data is limited or absent for this compound
—Injection-site redness, itching or soreness is the most commonly reported effect for injected research peptides

Histamine reactions

Possible at the injection site, as with most injected peptides.

Common fixes

Rotate injection sites (abdomen, thighs, upper arms) and stay at least an inch from the last spot.
Let the alcohol swab dry fully, let the solution reach room temperature, and inject slowly with a fresh needle.
A cold compress for 5–10 minutes eases a red or itchy welt; it should fade within a day.
For mild itching, redness or flushing, a non-drowsy over-the-counter antihistamine (such as cetirizine or loratadine) is commonly used — check with a pharmacist first, especially if you take other medicines.
Start low, change one thing at a time, and keep a log of how you feel.

Stop and get help

Any unexpected or severe symptom — stop and contact a doctor.
Stop and get emergency help for swelling of the face, lips, tongue or throat, trouble breathing, widespread hives, chest pain or fainting.

Basis: Limited data; general experience with injected peptides. Educational only, not medical advice.

Medication concerns

Theoretical: no human interaction studies

Prescription medicines in general
No human interaction studies exist for this compound, so its interaction profile is unknown. Unknown is not the same as safe.
Everything else you take, including supplements
Bring a full list of medicines and supplements to your pharmacist or clinician before starting.

Basis: No published human interaction data. Educational only, not medical advice. Never stop or change a prescribed medicine without your prescriber.

Protocols & tracking are members-only

Members see the research protocols for Follistatin-315, plan schedules, track every dose and vial, and ask the AI Advisor questions with cited sources. Try every Researcher feature free for 7 days, no card needed.

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