Follistatin 344
Also known as: FS-344
Follistatin 344 is a form of the naturally occurring protein follistatin, studied in early research for its reported ability to bind and inhibit myostatin. It is not approved for human use in Australia.
- Category
- Growth Factor
- Reported half-life
- Not well established; circulating follistatin is reported to be cleared rapidly
- Common forms
- Lyophilised powder for reconstitution, Injectable solution
- Research status
- Not approved for human use in Australia; investigated in preclinical and gene-therapy research, with limited early-stage trials in specific muscle conditions. No marketed general therapeutic product.
- Last updated
- 21 June 2026
Claimed effects
The following effects are reported or claimed by users and in early research. They are not established medical facts and many are not supported by large human trials.
- Reported to bind and inhibit myostatin, a negative regulator of muscle growth
- Early research indicates increased muscle mass in animal models
- Users report interest in muscle growth and recovery
- Claimed to also bind other TGF-beta family members such as activin
How it is reported to work
Follistatin 344 is reported to be an isoform of follistatin, a protein that binds members of the TGF-beta family including myostatin and activin. By sequestering myostatin, which normally limits muscle growth, follistatin is proposed to permit greater muscle development. These mechanisms come largely from animal and gene-therapy research and are not established for general human use.
Background
Follistatin 344 (FS-344) is a form of the naturally occurring protein follistatin, which is reported to bind and neutralise myostatin, a signalling molecule that normally limits muscle growth. Because of this, it has drawn research and online interest around muscle development. This page is educational information, not medical advice.
What the research actually shows
Follistatin has been studied mainly in animal models and gene-therapy research, where myostatin inhibition is reported to increase muscle mass. Some early-stage human trials exist for specific muscle-wasting conditions, but evidence supporting general use, and long-term safety, is lacking.
| Evidence type | Status |
|---|---|
| Animal/gene-therapy research | Present |
| Broad human trials | Lacking |
| Australian approval | None |
What people use it for (reported)
Online, people report interest in follistatin 344 in attempts to support muscle growth and recovery. These are anecdotal reports, not validated clinical results. Studies suggest a myostatin-binding mechanism, but reported benefits should not be read as established facts.
Things to be aware of
Follistatin 344 is not approved for human use in Australia. Interfering with myostatin and related TGF-beta pathways carries theoretical risks across many tissues, and grey-market product identity and purity cannot be verified by sight.
If you have a health concern, the appropriate step is to talk to a qualified healthcare professional rather than self-experimenting. This article is not an endorsement and does not recommend obtaining or using follistatin 344.
Reported positives & side effects
Compiled from research and community reports. These are reported outcomes, not guarantees or medical advice, individual experiences vary widely.
Reported positives
- Reported to bind and inhibit myostatin, a negative regulator of muscle growth
- Reported interest in increased muscle mass and recovery
- Reported increases in muscle mass in animal and gene-therapy research
- Reported broader activity against other TGF-beta family members such as activin
Common side effects
- Reported injection-site redness, swelling or soreness
- Reported temporary fatigue or malaise after dosing
- Reported mild headaches in some users
- Reported joint or tendon discomfort attributed to rapid muscle change
Rare / serious side effects
- Theoretical concerns around effects on reproductive and other tissues from activin inhibition
- Theoretical concerns that broad myostatin suppression could strain tendons and connective tissue
- Reported infection or abscess risk from non-sterile grey-market product
- Reported allergic-type reactions to impurities in unverified product
Reported misuse & overdose risks
What has been reported to happen with overuse, excessive dosing, or long-term misuse of Follistatin 344. Listed so you can make an informed decision, not to suggest any use is safe.
- Overuse is reported to suppress myostatin excessively, with concern that rapid, unregulated muscle growth could outpace and strain tendons and connective tissue.
- Broad inhibition of the TGF-beta family is reported to risk off-target effects on reproductive and other tissues with chronic misuse.
- Stacking with anabolic agents is reported to compound uncontrolled growth signalling and associated organ and connective-tissue strain.
- Reliance on unverified grey-market product is reported to carry contamination and dosing-error risks from unknown purity and potency.
Reported results timeline
Roughly how long people report it takes to notice effects. A general guide from reports, not a promise, and not advice. Users report little immediate effect, with any muscle-related changes reported to build gradually over several weeks of use.
First effects
Reported minimal early sensations beyond injection-site effects
Noticeable change
Reported subjective changes in muscle fullness building gradually
Clear results
Reported cumulative muscle-related effects over a longer block
Commonly reported dosing & protocol
Reported figures only, NOT a recommendation or dosing advice. These are numbers people report using, compiled for education so you can make an informed decision. We do not advise anyone to take Follistatin 344. Many peptides are not approved for human use in Australia. Speak to a qualified healthcare professional.
| Route | Subcutaneous injection |
|---|---|
| Typical reported dose | Reported community figures of roughly 100 mcg daily |
| Frequency | Reported as once daily |
| Cycle length | Reported in short runs of around 10–30 days |
Reported reconstitution (mg → units)
Illustration only: a 1 mg vial + 1 mL bacteriostatic water = 1 mg/mL. A 100 mcg (0.1 mg) dose is about 0.1 mL = 10 units on a U-100 insulin syringe.
Work out the units for your vial → CalculatorCommonly reported as short blocks of roughly ten days to a few weeks of dosing followed by extended breaks, framed as anecdotal reporting and not medical advice. Not approved for human use in Australia.
Best used with / commonly stacked with
Combinations people report using together. Reported, not recommended, stacking can increase risks.
Safety notes
Follistatin 344 is not approved by the TGA for human use in Australia, and broad human safety data is lacking. Inhibiting myostatin and related pathways carries theoretical risks across multiple tissues, and grey-market product purity cannot be verified by consumers. Anyone considering it should first consult a qualified healthcare professional.