Ironjulius is correct. for some reason cardarine is tougher to obtain compared to other sarm like lgd s4 and mk 2866. I believe a lot of the more recent studies has curbed production even by uncertified hormone powder manufacturers.
I know someone who ordered a bunch of cardarine powder and it took a long time to arrive, along with other sarm powder. Once it arrived a sample of each was sent out for testing and it came back comprised of a couple different hormone powder mixtures in one, gw was present as was methandrostenolone. Needless to say it had to be thrown out. The other powders came back mostly perfect, the free 50grams of Ostarine that was sent was also mixed with the same thing. But the main powder order of each of the other sarm powder was correct.
So yes gw501516 isnt being produced nearly as much, and if you arent getting it tested then you might wind up taking part cardarine part dianabol hahahaha. Cheeky!
Moral of the story, you must have your powders tested before production otherwise, you might be selling scheduled 3 drugs to consumers without even knowing it and then your in big trouble.