Dealers will cut drugs with absolutely anything my friend and even if you ask them right to their face if it contains an adulterant that will kill you if you put it inside your body, they will say no. You are in a very very difficult situation my friend ebcause from the start you are never in your lifetime going to ever find pure diamorphine (you would kill yourself if you ever did) and while you can be certain your heroin is cut, as DB so wonderfully points out you can test it to see if it contains heroin at all and isn’t something else, but you will never know what it’s actually cut with.
There are a few ways to find out but they involve hundreds of thousands of pounds worth of equipment, highly qualified individuals to operate them and a vast library of compounds to compare the results of those tests with to find out whether your smack has caffeine in it. Bit of a shitter isn’t it mate.
