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Decoding

Follistatin (FST-344)_

Also known as FST-344

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.

01

What is Follistatin (FST-344)?

Plain language first. The technical label stays, but it never stands alone.

Overview

Follistatin is a protein that binds and blocks myostatin, the body's natural brake on muscle growth. In plain terms: with the brake released, muscles can grow beyond their normal limit, an effect that is dramatic in animals but experimental in people.

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.

02

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.

  1. 01
    It binds and neutralises myostatin
    Removing the brake rather than pressing the accelerator.
  2. 02
    Muscle grows past its normal ceiling
    In animals the effect is striking and well replicated.
  3. 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.
  4. 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.

03

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
04

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 cycling across compounds →

05

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

your own mL
units · —
Enter your own volume

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

Your draw

200 / 100 units
200 units will not fit in a 100-unit syringe. It would take 2 separate draws, or you can mix with less water so it fits in one.
Full calculator with reorder date →Read a syringe →
06

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.

07

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.

08

Is Follistatin (FST-344) approved?

And where the numbers on this page come from.
Research only

No. Not FDA-approved.

Sold for research use only. Not cleared for human consumption or medical use.

  • DoseFrom research and community reports. No regulator has reviewed this dose.
  • Vial sizeFrom what vendors typically list; not a recommendation.
  • Reviewed22 July 2026
09

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 Bimagrumab, Ipamorelin + CJC-1295 blend, and IGF-1 LR3 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
BIMA300 residues
Bimagrumab

An experimental shot that strips fat while adding muscle.

Investigational
Dose
10 up to 30 mg/kg per month (trial doses)
How often
Monthly
IPA+CJCBlend
Ipamorelin + CJC-1295 blend

The popular growth-hormone combo in one shot, for muscle, recovery, and sleep.

Research only
Dose
~100 mcg CJC + 200-300 mcg ipa
How often
Daily, often at night
LR383 residues
IGF-1 LR3

A powerful muscle-builder that also drops blood sugar hard.

Research only
Dose
0.02 up to 0.05 mg per day (start low, increase slowly)
How often
Daily, cycled
Browse the full muscle-building lineup
10

What these words mean

Show glossary +
Titrate
Starting at a low dose and increasing it slowly over time so your body adjusts and side effects stay mild.
Subcutaneous
An injection just under the skin, into the fat layer, usually with a short, thin insulin needle.
Intramuscular (IM)
An injection into a muscle, using a longer needle.
Reconstitution
Mixing a powdered peptide with liquid (bacteriostatic water) so it can be drawn into a syringe.
Bacteriostatic water
Sterile water with a tiny amount of preservative, used to mix powdered peptides.
Concentration
How strong the mixed peptide is, in milligrams per milliliter (mg/mL). More water makes it weaker; less water makes it stronger.
Units (on the syringe)
The marks on an insulin syringe. 100 units equals 1 mL. They measure how much liquid you draw, not the dose in milligrams.
mcg and mg
Units of dose. 1 milligram (mg) equals 1,000 micrograms (mcg).
GLP-1
A natural gut hormone that lowers appetite and blood sugar. Drugs that copy it, like semaglutide, are used for weight loss.
Growth hormone secretagogue
A compound that nudges your body to release more of its own growth hormone, rather than injecting the hormone itself.
Half-life
How long a compound stays active in your body. A longer half-life means you inject less often.
Peptide vs small molecule
A peptide is a short chain of amino acids. A few items here (like MK-677 or methylene blue) are small molecules, not true peptides, but people use them the same way.
Research only
No approved dose or use in people. Sold for research and not reviewed by the FDA for safety or quality.
Investigational
Still being tested in clinical trials and not yet approved or legally sold for general use.
Banned in drug-tested sport
Prohibited by the World Anti-Doping Agency (WADA); using it can disqualify a competing athlete.

Last reviewed 22 July 2026