Follistatin (FST-344)_Dosage, benefits & legal status
Also known as FST-344, Follistatin, Follistatin-344, FS344
An experimental muscle-builder that releases the body's brake on growth.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Follistatin (FST-344)?
Plain language first. The technical label stays, but it never stands alone.Overview
With the brake released, muscles can grow past their normal limit. The effect is dramatic in animals and still experimental in people.
Follistatin is a protein that binds and blocks myostatin, the body's natural brake on muscle growth.
What it's used for
Blocks the natural brake on muscle growth so muscles can get bigger. It is very strong in animals; human use is experimental and expensive.
How does Follistatin (FST-344) work?
What it does in the body, and where.Follistatin blocks myostatin, the signal that limits how much muscle you can build. Animals lacking myostatin are visibly, dramatically muscular.
- 01It binds and neutralises myostatinRemoving the brake rather than pressing the accelerator.
- 02Muscle grows past its normal ceilingIn animals the effect is striking and well replicated.
- 03Human data is from gene therapy, not injectionThe trials used a virus to deliver the gene into muscle, at doses measured in viral particles. That has almost nothing to do with the protein sold for injection.
- 04Myostatin limits muscle for reasonsIt also regulates tendon and heart tissue. What happens when it is blocked long-term in humans is unknown.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Muscle growth by blocking the body's natural brake on itResearch only
- Muscular dystrophy, studied as a gene therapy in early trialsInvestigational
The published record
Papers and trials about Follistatin (FST-344)
Searched: Follistatin, FST-344, Follistatin-344, FS344.
255 papers tagged human · 166 not reviews or lab · 16 clinical trial publications
15 registered trials · 1 with posted results
Furthest stage reached: Phase 1, completed, no results posted
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Prohibited at all times, in and out of competition. S4.3 Myostatin-binding proteins (e.g. follistatin, myostatin propeptide). Non-Specified.RegulatorsCounted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count. 500 papers and 15 trials indexed in detail.
At a glance
Four things to know about Follistatin (FST-344)
How much, and do you cycle it?
The range, and whether you take breaks.Research only, cycled. Commonly cycled Community practice
Cycled by convention rather than to a tested schedule. No published study establishes a block length or a break length for this one.
Nothing publishedNo figure
No published human pharmacokinetic study.
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
Follistatin (FST-344) starts at $50.99 across 30 vendors, typically $54.99 – $169.00 per mg.
34 listings, last read Oct 24, 2026. Shipping and card fees are not included.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized Follistatin (FST-344) keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Any history of cancer, given the growth-promoting mechanism
- Pregnancy
- No established human safety profile
Stop and get help
- New lumps or masses
- Any severe or unexpected symptom
- Signs of an allergic reaction such as face or throat swelling, hives, or trouble breathing
Common effects
- Unknown in humans
- Theoretical risk of unwanted tissue or organ growth
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Follistatin (FST-344) approved?
And where the numbers on this page come from.No. Follistatin (FST-344) is not approved for any use, anywhere. It is sold labeled for laboratory research only, and there is no legal route to buy it for human use.
- Approval statusResearch only
- RouteUnder the skin (subcutaneous)
- Checked22 September 2026
- DoseFrom community reports. No regulator or trial established this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesNone traced yet.
What has happened recently
We have not yet written a full regulatory note for this compound. The status above is current as of the date shown.
What regulators say
From official documentsProhibited at all times, in and out of competition. S4.3 Myostatin-binding proteins (e.g. follistatin, myostatin propeptide). Non-Specified.
Checked 12 September 2026WADA: The 2026 Prohibited List (in force 1 January 2026)
You can compare this against the whole library, or read how to check a seller.
What else is like Follistatin (FST-344)?
Others in Muscle building, side by side.If you're weighing Follistatin (FST-344), it's worth reading MGF (Mechano Growth Factor), ACE-031 (Ramatercept), and IGF-1 DES in the same class.
An experimental muscle-builder that releases the body's brake on growth.
- Dose
- Research only
- How often
- Cycled
A local muscle-repair peptide injected near a worked muscle.
- Dose
- 0.1 up to 0.2 mg per dose (start low, increase slowly)
- How often
- Post-workout
An experimental muscle-builder whose development was paused over side effects.
- Dose
- 0.02 up to 3 mg/kg per dose
- How often
- Single dose in the trial
A short-acting muscle-builder that works right where you inject it.
- Dose
- 0.05 up to 0.15 mg per dose (start low, increase slowly)
- How often
- Around training
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
No primary source has been traced for this compound yet. Treat everything on this page as unverified until one is. How we grade evidence
Beyond these, 515 records are indexed. Browse the records