speed--> amphetamine sulphate
Amphetamine sulphate=/=Metamphetamines (MDMA)
MDMA or speed causing hairloss = wanking causing hairgrowth in the palm of your hand.
Although I don´t want to discard it could cause some type of loss via diet disorders, lack of sleep... or this dangerous behaviors associated with a raving way of life.
But I doubt VERY VERY much it could have any direct effect on hair.
MDMA was widely used by psichiatrist during the sixties, before the absurd prohibition, for treating certain diseases such as anxiety and sociopathy, there were some studies about the drug, and hair-loss was not remotely mentioned in any.
My thought after researching the topic, is that MDMA, like LSD, is a safe drug physiologically speaking.