Follistatin-344
Follistatin-344 (FST-344)
Also called Follistatin-344, FS-344, FST
Releasing the brake on muscle growth
Follistatin is your body's own myostatin blocker. Myostatin is the brake on muscle growth, and follistatin takes it off. Animals engineered to overproduce it grow strikingly muscular, which is where the interest comes from, and almost all of that work is gene therapy rather than an injected peptide.
A naturally occurring protein that binds and neutralizes myostatin and activin — the body's built-in limiters on muscle growth. By sequestering myostatin, Follistatin-344 removes a key brake on hypertrophy, which is why it's one of the most discussed (and still early-stage) research peptides for muscle and recovery.
- Half-life
- ~30 hours
- Route
- Subcutaneous injection
- Typical dose
- Research-dependent
- Availability
- Research-only
Human trials published, with more underway
What people use Follistatin-344 for
Reported uses, roughly in order of how often they are the reason someone goes looking. Whether it works for any of them is a separate question, answered under each one.
- Muscle growth
- The only reason anyone looks at it. Blocking myostatin removes the ceiling your body normally imposes, and the animal images that circulate are the reason it has a reputation at all.
- Muscle-wasting conditions
- Where the legitimate research sits, in muscular dystrophy and similar. Those programmes use gene therapy, not an injectable peptide.
Mechanism of Action
How Follistatin-344 works
Follistatin-344 works by neutralizing the growth-limiting TGF-beta ligands:
- Myostatin (MSTN) sequestration — binds circulating myostatin and blocks it from activating its receptor, lifting the primary genetic brake on muscle fiber growth.
- Activin inhibition — also binds activin, a related TGF-beta ligand, broadening its effect on the growth-suppression pathway.
- De-repressed satellite cells — with myostatin signaling reduced, satellite-cell activity and protein synthesis are less restrained, favoring hypertrophy.
- Local vs systemic — effect size depends heavily on baseline myostatin tone, which is strongly genetically determined — so responses vary widely between individuals.
Follistatin-344 dosage calculator
Enter what is in your vial, how much water you added, and the dose you are using. It works out where to pull the plunger to.
How much is in the vial?
Printed on the label, in milligrams
How much water did you add?
Bacteriostatic water, in millilitres
What dose are you taking?
The dose you already intend to use
Which syringe?
Barrel size, printed on the wrapper
Draw to
10 units
on a 0.5 mL insulin syringe (0.1 mL)
- Strength once mixed
- 5 mg/mL
- Doses in the vial
- 20
10 mg in 2 mL makes 5 mg/mL. A 500 mcg dose is 0.1 mL of that, which is 10 units.
This is arithmetic, not advice. It converts a dose you already have into a mark on a syringe. It does not tell you what dose to take, and Follistatin-344 is not prescribed by us. Dosing belongs with a qualified clinician.
Follistatin-344 side effects: what people reported
Very little reported, and the gap between what people expect and what is documented is wider here than almost anywhere else in this catalogue.
What people report
- Injection-site reactions
- Little else, consistently
The honest concern
- Myostatin limits muscle growth for reasons, and heart muscle is muscle. Sustained blockade has raised questions in animal work about the heart and tendons that no human study has answered
- Injected follistatin has a very short life in the body, which is one explanation for why so little is reported: it may not be doing much at all
Source: Animal and gene-therapy research; no human trial of injected follistatin. This is a summary of published findings, not a complete safety profile and not medical advice. Follistatin-344 should only be considered with a qualified clinician who knows your history.
Your Genetics & Follistatin-344
The genes involved in how Follistatin-344 works
Follistatin-344 works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
The K153R variant alters myostatin activity. Your baseline myostatin tone sets how much brake there is to release — people with naturally higher myostatin signaling have more to gain from neutralizing it with Follistatin-344.
ACTN3 · ••
The R577X variant determines alpha-actinin-3 in fast-twitch fibers. Fiber-type genetics shape the hypertrophy ceiling and how much a myostatin-blocking peptide translates into visible muscle.
IGF-1 promoter variants set the anabolic signal that builds muscle once the myostatin brake is released. A stronger IGF-1 background amplifies the net effect of Follistatin-344.
VDR · ••
The FokI variant influences muscle strength and mass response to training. It shapes the muscular background on which a myostatin-blocking peptide acts.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which variants do you carry?
Upload your DNA data, or get tested through our partner, to find out.
Commonly combined with
What Follistatin-344 is most often paired with, and why:
IGF-1
Muscle StackModerate EvidenceInsulin-like Growth Factor-1
The primary anabolic mediator of growth hormone. Most of GH's effects on muscle, tissue repair and growth are actually carried out by IGF-1, produced mainly in the liver. Native IGF-1 is short-acting and tightly regulated by binding proteins — making the IGF axis one of the most genetically variable in the body.
4
Gene variants
45+
Studies
CJC-1295
GH Axis StackModerate EvidenceCJC-1295 (Modified GRF 1-29)
A copy of the brain signal that tells the pituitary to release growth hormone, rewritten so the enzyme that normally destroys it in minutes cannot. Before you read any dose, check which version you have: with DAC it keeps growth hormone up for days, without DAC it produces a short pulse, and nearly every blend sold with ipamorelin contains the second one.
4
Gene variants
30+
Studies
ACE-031
Myostatin StackEmerging EvidenceACE-031 (Ramatercept)
A soluble decoy version of the activin receptor type IIB (ActRIIB). ACE-031 acts as a trap — it circulates and binds myostatin and related growth-limiting ligands before they can reach muscle, removing the brake on growth. It reached human trials for muscular dystrophy but was discontinued over vascular safety signals, so it remains research-only.
4
Gene variants
15+
Studies
Sourcing & access
Where to buy Follistatin-344
Follistatin-344 is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Follistatin-344
Releasing the brake on muscle growth
$139.99at Swiss Chems
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Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you). Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Worth knowing before you consider Follistatin-344
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- The famous results are gene therapy, not injections
- The muscular animals people have seen came from genetic modification producing follistatin continuously. Injecting a protein that clears in minutes is a different thing entirely.
- Tendons do not grow with the muscle
- The consistent worry with anything that removes the brake on muscle: connective tissue does not keep pace, and that mismatch is where injuries happen.
Last updated
Frequently Asked Questions
How does Follistatin-344 build muscle?
It doesn't build muscle directly — it removes a brake. Myostatin is a protein your body produces to limit muscle growth. Follistatin-344 binds and neutralizes myostatin (and activin), so the natural anabolic drive faces less resistance. How much that helps depends on how much myostatin you produce, which is genetic.
Why do results vary so much with Follistatin-344?
Because the effect depends on your baseline myostatin tone and muscle genetics. Someone with naturally high myostatin signaling has more brake to release; someone already low in myostatin (or carrying favorable muscle variants) may see less. MSTN and fiber-type genetics are the key predictors.
Does genetics affect Follistatin-344 response?
Yes. MSTN variants set how much myostatin brake there is to release, ACTN3 fiber-type genetics shape the hypertrophy ceiling, IGF1 sets the anabolic background, and VDR influences muscle response. A genetic peptide report profiles these for realistic expectations.
Your next move
Two ways forward with Follistatin-344.
Not sure it's for you?
How does Follistatin-344 relate to your genes?
Your report scores Follistatin-344 against your receptor, pharmacogene and pathway variants and shows the genetic markers relevant to it, with commonly cited dosing information to review with a clinician.
Analyze my DNA — $99Already decided?
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