I've got a theory (and that's all it is - not enough people reporting exactly what they used, where they got it, and what their results were), and I hope by posting this people in the market for Follistatin will start asking some questions and thereby get the manufacturers to create better products.
The theory is this: E. coli-derived FS344 doesn't work. There is no reason it should, since what is found in the bloodstream is actually FS315 (a by-product of FS344 that your cells convert - but if you inject it, you bypass the cells and they don't have a chance to convert it).
This could explain why some people report great results from Follistatin and others say it's trash. They are actually using different products.
I'm fairly confident (see my other posts for all the technical detail, with references) that, for purposes of injecting the FS protein (which is different than what is done with the viral version), people should be using FS315, preferably without some kind of artificial tag on the end.
The best way to denote the correct product, and nothing else extra, would be to describe it as being "amino acids 30 to 344 of FS344," or "FS315" (with no tag).
If you are in the market, I would suggest not buying anything else, and ask the manufacturers who are selling full-length FS344 why anyone would want FS344 when the mature form that is actually found in the blood is FS315. It's no harder for them to make FS315 than FS344. They just didn't bother to investigate the biology before they started making it.
