In August 1995 Quinn et al released a study called “Interleukin-15: a novel cytokine anabolic for skeletal muscle.”
We all know most pro-bodybuilders don’t read all the new studies, but most athletes hire people that make a living by supervising professional bodybuilders and other athletes such a tennisplayers, footballplayers, cyclists etc etc.. In bodybuilding were nutrition and supplementation is very important these people are mostly called “nutritionists.”
As Dr Larkins from Australia said: "There's a whole generation of sports science people coming through who are well trained in sports performance areas and what I call genuine areas but many, many sports and clubs have got these people.”
Well the keywords “anabolic for skeletal muscle” did ring a bell. Of course bodybuilders already worked with other interleukins, like by example IL-6. Soon several studies on Il-15 popped up, also again from Quinn in 2002 “Overexpression of interleukin-15 Induces skeletal muscle hypertrophy in vitro.” Most studies were performed on rodents in high amounts. Thus it was hard to translate results to bodybuilders and athletes dieting and training hard.