![Follistatin 344 [1mg]](https://vipresearchpeptides.com/wp-content/uploads/2026/10/follistan.jpg)
$125.00
Follistatin-344 is an investigational research compound studied for its interaction with myostatin and activin pathways involved in muscle-growth regulation. Most evidence comes from preclinical studies; human findings are limited, and important safety questions remain.
For laboratory research only. Not for human or animal consumption.
Follistatin-344 Ā· Research Profile
Follistatin-344 has been studied for its interactions with myostatin
and activin, proteins involved in regulating muscle growth. Most
evidence comes from laboratory and animal research. Human findings
remain limited, and important safety questions remain.
Background
Follistatin-344 is a form studied in muscle biology. The supplied
material describes it as being processed into follistatin-315 after
secretion. It also notes that follistatin-344 binds activin less
tightly than the membrane-bound follistatin-288 form.
Research has examined recombinant protein, messenger RNA (mRNA),
and AAV1 gene therapy approaches. These are distinct research
methods and do not establish the safety or effectiveness of
other forms or uses.
| Research focus | Myostatin and activin signaling |
|---|---|
| Related pathways | SMAD and Akt/mTOR/S6K signaling |
| Methods studied | Protein, mRNA, and AAV1 gene therapy |
| Evidence base | Primarily preclinical, with limited human studies |
Proposed Mechanisms
Follistatin can bind myostatin, a member of the TGF-Ī² superfamily
that is involved in limiting muscle development. Binding may prevent
myostatin from interacting with activin type II receptors on muscle
cells.
Follistatin also binds activin. The supplied material describes
activin neutralization as another possible way to affect signaling
pathways involved in muscle growth regulation.
Research has examined effects on the SMAD signaling cascade and
Akt/mTOR/S6K pathways associated with protein synthesis and cell
growth.
Studies have explored whether follistatin-related signaling can
recruit muscle precursor cells, which may contribute to muscle
fiber growth and repair in experimental models.
The supplied material also describes myostatin-null mouse research
in which follistatin was associated with further muscle growth.
This suggests that pathways beyond myostatin may contribute to
findings in those models.
Research Findings
Mouse studies reported substantial muscle changes. The supplied
material describes local muscle gains of more than double in one
28-day study and gains lasting over two years after a single
AAV1-FS344 treatment in aged mice.
Other mouse findings included a 60% increase in limb muscle force
capacity in one model, increases in muscle-fiber area, and changes
in dystrophic mdx mice, including larger fiber diameters, lower
creatine kinase, reduced muscle-tissue necrosis, and less fibrosis.
In a cynomolgus macaque study, animals received bilateral quadriceps
injections of AAV1.CMV.FS344. The supplied material reports a 15%
increase in quadriceps circumference at eight weeks, maintained
through 60 weeks, and a 34% increase in mean muscle-fiber diameter.
An early study treated six patients with Becker muscular dystrophy
using AAV1.CMV.FS344 and reported functional improvements. The
supplied material notes that the study lacked a placebo control
and was later criticized for possible performance bias.
A later reflection from the lead researcher described myostatin
inhibition as not working well compared with expectations. A
follow-up study in nine patients with sporadic inclusion body
myositis had similar methodological limitations.
Preliminary research has explored possible anti-inflammatory,
metabolic, bone, and hair-related effects. The supplied material
describes findings involving TNF and IL-1Ī² in an endotoxemia model,
pancreatic beta-cell research, possible bone-density effects, and
one pilot hair study reporting a change in follicle thickness.
These findings are preliminary and require replication in
controlled human research.
Research Limitations
The supplied material describes dramatic muscle findings in animal
models, but notes a substantial gap between laboratory results and
real-world human outcomes. The limited human studies do not establish
a reliable benefit for general muscle growth.
Results from gene therapy studies, animal models, or one formulation
should not be assumed to apply to other products or methods.
Safety Research
The supplied material describes two-year reproductive studies in
FS-344-treated mice that found normal litter sizes and no gonadal
tissue changes. It also describes 2025 research in which myostatin-
neutralizing antibodies reduced FSH levels by 75% within one week
and decreased ovulation in female animals.
The reported FSH findings concern myostatin-neutralizing antibodies;
they do not establish the same effect in humans using follistatin.
The material identifies reproductive effects as an area requiring
further study.
The supplied material describes a 2020 case series of 11 male
bodybuilders who developed central serous chorioretinopathy (CSCR)
after subcutaneous follistatin-344 injections. It reports that all
had injected complete 1 mg vials, and that some cases recurred after
multiple injections.
The reported mechanism is unclear. These cases raise a safety
concern; they do not establish how often the condition occurs.
Myostatin-deficient mouse research has reported weak or brittle
tendons. Whether long-term interference with myostatin could have
similar effects in humans is unknown.
The supplied material describes different associations across
tissues: higher follistatin levels have been associated with better
outcomes in some breast-cancer research, while other findings
describe possible concerns in prostate and thymic tumors.
The relationship between follistatin, activin signaling, and cancer
is complex. The available information does not establish the
long-term cancer risk in humans.
Evidence & Safety
Follistatin-344 has produced substantial muscle-related findings in
some animal studies. Human research has been limited, and early clinical
findings have important methodological limitations. Animal and
laboratory results do not establish human safety or effectiveness.
The supplied material also raises concerns involving vision, fertility,
tendon health, cancer-related pathways, and the quality of products
sold outside controlled research. It reports that more than half of
tested black-market products contained no follistatin or had
contamination, but that figure should be understood as a claim from
the supplied source.
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