I don't think anyone should use it, ever. It nearly killed Milos Sarcev when he injected it to his tricep. And if it's too dangerous for an expert like him, it def. is too dangerous for anyone else. Even if it doesn't give you any noticeable health issues it does not look good at all. It's not muscle, it is simply oil deposits. Some say that competing athletes could use it as a "finishing touch" and some do, but 9/10 times they end up wasting their hard work and diet for their competition, forget it.