How much water do I add to Follistatin (FST-344)?

You can reconstitute Follistatin (FST-344) with 0.5, 1, or 2 mL of bacteriostatic water. Each option produces a different concentration and syringe draw for the same dose. Use the calculator to see which is easiest to measure.

What does Follistatin (FST-344) cost per dose?

Cost per dose depends on vial size, price paid, and your dose. Enter your vendor's price in the Follistatin (FST-344) calculator to see cost per dose and monthly cost.

What is the reference dose for Follistatin (FST-344)?

The commonly referenced range is Research only, taken cycled. This is reference information, not a recommendation. Talk to a licensed clinician.

What are the side effects of Follistatin (FST-344)?

Reported side effects of Follistatin (FST-344) include: High risk: long-term safety is unknown, with a theoretical risk of unwanted tissue or organ growth.. Severity and frequency vary by person and dose.

Who should not take Follistatin (FST-344)?

Follistatin (FST-344) is generally not appropriate for: Any history of cancer, given the growth-promoting mechanism; Pregnancy; No established human safety profile. Talk to a licensed clinician before starting.

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Decoding

Follistatin (FST-344)_Dosage, benefits & legal status

Also known as FST-344, Follistatin, Follistatin-344, FS344

By the Peptide Decoding Editorial Team

Published July 22, 2026 · Updated August 14, 2026

An experimental muscle-builder that releases the body's brake on growth.

Muscle growthMyostatin inhibitorResearch onlyHigh-risk

InMuscle building

Common vial size1 mg

DoseResearch only

FrequencyCycled

RouteUnder the skin (subcutaneous)

StatusResearch only

MixYour choice, calculate it

CycledCommonly cycled

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.

The technical version

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.

01
It binds and neutralises myostatin
Removing the brake rather than pressing the accelerator.
02
Muscle grows past its normal ceiling
In animals the effect is striking and well replicated.
03
Human data is from gene therapy, not injection
The 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.
04
Myostatin limits muscle for reasons
It also regulates tendon and heart tissue. What happens when it is blocked long-term in humans is unknown.

Where it acts

Muscle

Where this compound is thought to act.

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

Research index

3,227

Records indexed for Follistatin (FST-344)400 papers and 15 trials indexed in detail.

207 in humans, 147 of them original studies.

15 registered trials, 1 with posted results.

Browse the records

In animalsPro

In the labPro

ReviewsPro

Senior author sharePro

Counted from Europe PMC indexing, not read by a person. Human means indexed under humans, which includes reviews and work on human cells. Original studies exclude reviews and lab work on human cells.Last updated 12 September 2026.

Compound field notes

At a glance

Four things to know about Follistatin (FST-344)

Evidence

Research only

How much, and do you cycle it?

The range, and whether you take breaks.

Research only, cycled. Commonly cycledCommunity practice

Cycled by convention rather than to a tested schedule. No published study establishes a block length or a break length for this one.

Compare this against the whole library →

How long does it stay in the body?

The half-life, and where the figure comes from.

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.

Your vial size (mg)

Printed on the vial.

What you paid per vial

Used for cost per dose only.

Your dose (mg)

Commonly referenced range: Research onlyNo range

Choose your mix

0.5 mL water—units · 2 mg/mL

Half a 100-unit syringe

1 mL water—units · 1 mg/mL

One full 100-unit syringe

2 mL water—units · 0.5 mg/mL

Two full 100-unit syringes

your own mL

units · —

Enter your own volume

Measuring the water1 mL = one full 100-unit syringe.

Your draw

0 / 100 units

Full calculator with reorder date →Read a syringe →

What it costs

Follistatin (FST-344) starts at $50.99 across 15 vendors, typically $54.99 – $182.75 per mg.

30 listings, last read Sep 6, 2026. Shipping and card fees are not included.

See all 30 listings →

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

Check these before anything else.

Any history of cancer, given the growth-promoting mechanism
Pregnancy
No established human safety profile

Stop and get help

These are emergencies. Seek care.

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

Expected, and usually mild.

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 labelled for laboratory research only, and there is no legal route to buy it for human use.

Approval status
Research only
Route
Under the skin (subcutaneous)
Checked
September 2026

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.

You can compare this against the whole library, or read how to check a seller.

DoseFrom research and community reports. No regulator has reviewed this dose.
Vial sizeFrom what vendors typically list; not a recommendation.
Sources
Mendell et al., a phase 1/2a follistatin gene therapy trial for Becker muscular dystrophy ClinicalTrials.gov NCT01519349, follistatin gene transfer in Becker muscular dystrophy and sporadic inclusion body myositis
Reviewed8 September 2026

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), PEG-MGF, and ACE-031 (Ramatercept) in the same class.

YOU ARE HERE

FST344 residues

Follistatin (FST-344)

An experimental muscle-builder that releases the body's brake on growth.

Research only

Dose: Research only
How often: Cycled

MGF

MGF (Mechano Growth Factor)

A local muscle-repair peptide injected near a worked muscle.

Research only

Dose: 0.1 up to 0.2 mg per dose (start low, increase slowly)
How often: Post-workout

PEG-MGF

A longer-lasting muscle-repair peptide on a less-frequent schedule.

Research only

Dose: 0.2 up to 0.4 mg per dose (start low, increase slowly)
How often: 1-2x per week

ACE-031Antibody

ACE-031 (Ramatercept)

An experimental muscle-builder whose development was paused over side effects.

Research only

Dose: Trial doses
How often: Cycled

Browse the full muscle-building lineup

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

Mendell et al., a phase 1/2a follistatin gene therapy trial for Becker muscular dystrophy(2015)
Six participants. This was AAV1.CMV.FS344 gene therapy delivered by direct bilateral intramuscular injection into the quadriceps, not an injected peptide. Two subjects improved on the six-minute walk test and the third showed no change.
ClinicalTrials.gov NCT01519349, follistatin gene transfer in Becker muscular dystrophy and sporadic inclusion body myositis(2015)
Registry record for the gene transfer trial, run at a single site. The supporting work includes non-human primate studies of follistatin gene delivery. Every human study of follistatin is gene therapy.

Last reviewed 8 September 2026

Beyond these, 415 records are indexed. Browse the records