Was reading about this compound and it sounds very interesting here is some info.

Interluekin 15 is a cytokine thats highly expressed in skeletal muscle. Cell structure studies have shown that IL-15 may have an important role in muscle fiber growth and anabolism. However dat concerning the metabolic effects of this cytokine in vivo are lacking.

In a brief study, IL-15 was administered for seven days to adult rats. Though it did significantly affect both protein synthesis(anabolism) and degradation(catabolism) in favour of growth, the amazing result was in the effects it had upon adipose tissue and blood lipids. After only seven days of administration, the adult rats realized a 33percent decrease in white adipose tissus(bodyfat) and a 25 percent decrease in circulating triglycerides.

IL-15 on paper seems to be more effectual than igf1 and far safer, even though together they are 5 times more anabolic than either alone.

There is one downfall however a 30 day protocol of IL-15 can cost as much as $20,000. Although im sure with time the price will drop.