Follistatin 344: what the mouse, cell and macaque studies measured

What is follistatin 344, and what does the search ask?

Myostatin is a member of the transforming growth factor-beta family that limits skeletal muscle mass [1]. Follistatin is known as an activin-binding protein, and in 2001 researchers showed that it also blocks myostatin from binding its receptor, ActRIIB [1]. FS344 is the label used for one alternatively spliced form of the human follistatin gene, chosen because it acts on skeletal muscle with only minimal effects on other cells [3].

Searches for follistatin 344 tend to treat it as a vial peptide with a dose. The sources below did something different: they made animals produce follistatin from a gene. That gap between the literature and the search is the main thing this page sets out to explain.

What do the follistatin studies report?

The 2001 paper started in the test tube: purified myostatin bound the activin type II receptors, and follistatin inhibited that binding [1]. The same group then bred mice whose skeletal muscle made high levels of follistatin. Those transgenic mice showed large increases in muscle mass, comparable to mice with no myostatin gene at all.

A 2008 mouse study gave a single gene administration of myostatin-inhibiting proteins and reported larger and stronger muscles in normal and dystrophic mice for more than two years, including when delivered to older animals [2]. The authors presented this as a lead for muscle disease, not as a finding in people.

In 2009, researchers injected AAV1-FS344, a viral vector carrying the FS344 gene, into the thigh muscles of cynomolgus macaques [3]. Muscle size and strength increased and stayed up, and long-term expression caused no abnormal changes in key organs in the animals studied. The authors disclosed a provisional patent on the approach.

None of these studies injected a manufactured follistatin peptide under the skin, and none measured a human amount. Mice and macaques also differ from people in muscle biology, delivery route and follow-up, so even the strongest animal result here is a starting point for research, not a prediction. The figure lists what kind of evidence exists, and the empty rows matter as much as the filled ones.

How would follistatin 344 be measured and converted?

Unit arithmetic needs a labeled amount and a liquid volume, and here both are missing. The cited studies delivered a gene in a viral vector, so their quantities are vector doses, not milligrams of protein, and they do not convert into a peptide vial [2][3]. PinPoint's library has no entry to supply a package example [4].

The rule for any product that does print an amount and a volume is unchanged: amount divided by volume gives concentration, and millilitres times 100 gives U-100 units [5]. The peptide calculator does that step from label values. Any follistatin figure in micrograms per syringe unit has to come from a product label, because no source on this page provides one.

How do people log follistatin in PinPoint?

PinPoint's compound library has no follistatin entry [4]. The app's library covers peptides such as BPC-157, TB-500, ipamorelin and CJC-1295, along with TRT and GLP-1 medicines, and the peptide library lists every compound guide [6].

For library compounds, entries record compound, dose, site and pain level, and site rotation suggests where to inject next [6]. Side effects with severity ratings and daily notes sit beside the dose history. Ask PinPoint summarises what published references say about a compound in the library and never recommends a dose or a change [6]. If follistatin ever reached the library, its guide would supply the half-life input and package example that vial setup and the Home curve depend on.

What do people ask about follistatin 344?

What is follistatin?

Follistatin is a protein made in the body that binds activin and blocks myostatin, a signal that limits muscle growth. FS344 names one form of its gene.

Is there a human follistatin 344 dosage?

No human amount appears in the cited sources. The studies used cells, transgenic mice, gene delivery in mice and gene delivery in macaques.

What did follistatin do in mice?

Mice engineered to make extra follistatin in muscle developed much larger muscles, and a single gene delivery of myostatin inhibitors gave larger, stronger muscles for over two years. Those were animal results.

Is follistatin 344 FDA approved?

The studies cited here are preclinical and say nothing about approval, and this page cites no FDA approval record for follistatin 344.

Where do these facts come from?

Sources are listed by kind: labels first, then peer-reviewed papers, then PinPoint's own library, arithmetic and app description. Library values were retrieved from the PinPoint application on 5 October 2026; vendor listings support package sizes only.

1. Regulation of myostatin activity and muscle growth, 2001Proceedings of the National Academy of Sciences, 2001. Binding studies with purified myostatin and transgenic mice expressing follistatin in skeletal muscle.Retrieved 2026-10-05 · study
2. Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors, 2008Proceedings of the National Academy of Sciences, 2008. One-time gene delivery of myostatin-inhibitor proteins in normal and dystrophic mice, followed for more than 2 years.Retrieved 2026-10-05 · study
3. Follistatin gene delivery enhances muscle growth and strength in nonhuman primates, 2009Science Translational Medicine, 2009. AAV1-FS344 injected into the quadriceps of cynomolgus macaques.Retrieved 2026-10-05 · study
4. PinPoint compound library, application recordsHalf-life inputs, routes, frequencies, package examples and confidence labels as stored in the iOS app library and mirrored in the peptide guides.Retrieved 2026-10-05 · library
5. Unit conversion arithmeticConcentration = amount / volume; volume = amount / concentration; U-100 units = mL x 100; remaining fraction = 2^(-elapsed / half-life).Retrieved 2026-10-05 · arithmetic
6. PinPoint App Store descriptionFeature wording from the approved application description, not pricing.Retrieved 2026-10-05 · app-description