Yeah, it is safe. As any other steroids SARMs are made for almost everyday use so it is not dangerous at all. I can assure you of it from my personal experience. I've been using them for half a year now and everything seems just fine If you wanna read from a reliable source, check this out theihcc.com and you should find there answers to your questions. Anyway, I am no doctor to say for sure but to my mind if you overuse them then definitely something bad might happen... So, people who don't know what they are using them for should not use them at all.