My friend is taking muscle enhancement pills can they be addictive?

My friend keeps bying muscle pills and dietary supplement pills and they are all basicly the same thing but like 3 to 6 different kinds and he is buying them every month sometimes 2 times a month from the internet and depending on which ones he buys they cost any where from 50 to 200 dollars totaling after buying them all together when he buys them I'm affraid he is going to get addicted can you get addicted from these pills and he also just bought 3 differnt kinds a week ago and now they are gone so now he wants more please help and keep in mind this is 30 pills in one bottle for a month supply 60 in one for a month supply and 90 in another for a month supply so that's totaling 180 pills he was supposed to take in a month and took them in 5 days