What exactly is folisstatin 344, and does it actually work to build muscle?
Follistatin is an intriguing protein that can grow muscle mass above and above what is normally possible by inhibiting the action of myostatin. The first time that follistatin was discovered, researchers were looking at the follicular fluid that was found in the ovaries of pigs. 
Follistatin is a naturally occurring protein that may be discovered in the skeletal muscle of nearly all mature or evolved mammalian species, including but not limited to humans, rats, and cows. Follistatin has a high concentration of the amino acid cystine, which is considered to be a non-essential amino acid. However, unlike the majority of proteins that are studied in the realm of fitness, follistatin also includes carbs connected to it. 
Folistatin, more precisely Follistatin 344 (FS344), is becoming more well-known in the bodybuilding scene as a possible supplement that can fast enhance the amount of lean tissue mass. In terms of the muscle-building capabilities it possesses, another protein called follistatin-related gene (FLRG) functions on the same kinds of pathways as FS344.
Follistatin and the Development of Muscle
In addition to inhibiting the degenerative effects of myostatin, follistatin also inhibits the pituitary gland’s production of follicle-stimulating hormone and the hormone’s release into the bloodstream (FSH).  High FSH levels in males may be an indication that their testicles are not working properly; this condition inhibits the natural development of muscular tissue, as well as recuperation and the production of hormones.  Having an FSH level that is too low, on the other hand, might have a severe influence on both a person’s health and their reproductive capacity.
Increased levels of FS344 were found up to 15 months after the initial injection, in contrast to the requirement for daily treatment that is placed on certain myostatin inhibitors, such as Trichostatin A (TSA).   Because it does not require administration on a regular basis, follistatin is an appealing alternative treatment option for myostatin suppression.
The primary motivation behind the recent surge in interest shown by the scientific community in follistatin and other myostatin blockers is the quest for an alternate method to treat muscle disorders. The most common treatment option available today is androgen steroids, which are associated with a number of negative effects as well as potential dangers to the patient’s health in the long run. At this point, you might be asking why the usage of follistatin isn’t more prevalent in the world of bodybuilding and other types of athletics.
Does Folistatin Contribute to Muscle Growth?
In a nutshell, follistatin is capable of building muscle, but it may not do so in people. In mice, the effects of follistatin have been demonstrated to be both muscle-building and anti-degenerative, according to a number of studies. A simple Google search will turn up innumerable amateur follistatin logs on bodybuilding and fitness forums; however, there is no legitimate study that examines the use of follistatin in human beings.
In comparison to the mice that were used as a control group, the mice that were bred by scientists to produce no myostatin and excess follistatin resulted in animals that had muscle fibres that were 117 percent bigger and 73 percent more total muscle fibres.  The results of this study show that follistatin has a favourable influence on muscle development in a variety of different ways, in addition to its ability to inhibit myostatin. Mice that had their myostatin levels reduced had twice the amount of muscle mass as the control group, whereas mice that also had their follistatin levels reduced had four times the amount of muscle mass as the control group. 
There are no significant adverse effects on organs, reproductive skills, serum estradiol (also known as the primary female sex oestrogen), luteinizing oestrogen (LH), or FSH levels when FS344 is administered through a small virus (also known as an adeno-associated virus or AAV). This treatment can increase muscle size and strength in species of animals tend to range from mice to monkeys.
  When follistatin was given to mice with spinal muscular atrophy by researchers, the mice had increased muscle mass, enhanced motor function, and a lifetime that was thirty percent longer than that of animals in the control group. 
Not only is there a correlation between higher follistatin levels and increased muscle mass, but there is also a clear correlation between a lack of the follistatin protein at birth and decreased muscle mass.  A low muscle mass at birth can have detrimental effects on the development of bones, organs, and other tissues, as well as the appropriate action of hormones.
The Use of Follistatin by a Bodybuilder
The Dangers of Using Follistatin with Human Grade
A single milligramme of human-grade follistatin may set you back more than $4,500, which is an incredibly steep price tag.  Even the websites that offer follistatin in bulk stress that it should not be used in people and should only be used for research. However, this does not prevent bodybuilders from experimenting with this substance; amateur diaries seen online commonly dose FS344 at one injection of one hundred micrograms (mcg) each day for a period of ranging from ten to thirty days.
Some users even tried doses of more over 200 mcg, but this did not cause the effects to become any more prominent. In point of fact, the vast majority of consumers reported that the product had no effect whatsoever. A small number of users reported that injections of FS344 had amazing benefits on mass gain; nevertheless, if you analyse their logs, it appears that FS344 increased their hunger; some users increased the number of calories they consumed from 4,000 to more than 6,000.
When you drastically increase the number of calories you consume over and beyond what your body needs on a daily basis, you will experience weight gain. The users who were logging FS344 while they were going through a fat loss phase discovered that it did not assist maximise fat loss or retain lean muscle any more efficiently than they would have been able to do it without utilizing FS344. It is also important to point out that all of these FS344 logs were all on pro-anabolic-androgenic drugs (AAS), and almost all of the users were also using a variety of additional anti and AAS in conjunction with FS344.
In conclusion, follistatin is a protein that has the potential to play a significant role in halting the breakdown of muscle tissue and promoting the growth of new muscle mass. However, due to its high price tag and the paucity of research conducted on human subjects, it is not recommended for the average athlete or even the most experienced athletes.