This is something I have thought about. I used to take the Effedrine Caffine and Aspirin stack. After researching it I don't think these substances will cause hairloss. But, they do put alot of stress on your body which can cause hair loss.
You might not have to worry about this much longer because ephedra was just banned by the government. It should take a month or 2 to pull it all off the shelves. Not sure what the exact date is.