Follistatin (FST) is a secreted glycoprotein that was first identified as a follicle­stimulating hormone inhibiting substance in ovarian follicular fluid. Human Follistatin cDNA encodes a 315 amino acid (aa) protein with a 29 aa signal sequence, an N­terminal atypical TGF binding domain, three Follistatin domains that contain EGF­like and kazal­like motifs, and a highly acidic C­terminal tail. Follistatin is a secreted protein that binds to ligands of the TGF-Beta family and regulates their activity by inhibiting their access to signaling receptors. It was originally discovered as activin antagonists whose activity suppresses expression and secretion of the pituitary hormone FSH (follicle stimulating hormone).

In addition to being a natural antagonist, follistatin can inhibit the activity of other TGF-Beta ligands including BMP-2,-4,-6,-7, Myostatin, GDF-11, and TGF-Beta1. Follistatin is expressed in the pituitary, ovaries, decidual cells of the endometrium, and in some other tissues. Recombinant human Follistatin 315 is a 34.7 kDa protein containing amino acids 30-315 of the FST-315 protein.


Follistatin works by binding to and inhibiting transforming growth factor-β (TGF-β) peptides such as myostatin which is responsible for regulating and limiting muscle growth. It’s also worth pointing out that myostatin may have a regulatory role in skeletal muscle fibrosis; too much myostatin can impair tissue function and cause chronic disease in vital organs, tissues, and bone marrow.

In additional to suppressing the degenerative properties of myostatin, follistatin also suppresses the pituitary gland synthesis and secretion of follicle-stimulating hormone (FSH). High FSH levels in men may indicate that testicles are not functioning correctly; this condition limits muscle growth, recovery, and normal hormonal function.  However, FSH levels that are too low can also negatively impact health and reproductive capabilities.

Whereas some myostatin inhibitors like Trichostatin A (TSA) require daily administration, increased levels of FS were observed up to 15 months after initial injection. The lack of need for daily administration makes follistatin an attractive alternative for suppressing myostatin.

The recent increase in attention in the science community on follistatin and other myostatin inhibitors is primarily due to the desire to find an alternative means to treat muscle disorders; the most popular current option is androgen steroids which pose a number of side-effects and long-term health risks.




Note; dosage information is only for scientific reference purposes. SARMs Central, does not condone the human consumption or use of this substance outside of a controlled scientific environment (i.e. a lab).

If you are new to using Follistatin start with 100mcg and up the dosage to 200mcg until you are satisfied with the effect.

For best result Follistatin should be taken in conjunction with a high calorie diet.

Like most peptides, this formula comes in a dried format, which means that you will need to reconstitute it yourself. When you do so, you must use bacteriostatic or sterile water, both are safe for injections. Once powder in the vial is diluted and is in liquid form it is then withdrawn and injected using insulin syringes. When it comes to self-injection, its highly important to educate yourself and be careful. Peptides are usually injected intramuscular or subcutaneous (IM or Subq).

Potential Side Effects

There are currently no known side effects for Follistatin if the correct dosages are taken.

Find a distributor