In November 1942, the Italian cyclist Fausto Coppi took "seven packets of amphetamine" to beat the world hour record on the track.  In 1960, the Danish rider Knud Enemark Jensen collapsed during the 100 km team time trial at the Olympic Games in Rome and died later in hospital. The autopsy showed he had taken amphetamine and another drug, Ronicol , which dilates the blood vessels. The chairman of the Dutch cycling federation, Piet van Dijk, said of Rome that "dope – whole cartloads – [were] used in such royal quantities." 
So can you win clean? As much as I’d like to think so, when you have this situation where a guy finishing in the top 10 is using drugs and being beaten by minutes on a mountain climb , I find it difficult to believe that physiologically, the margins can be that large. I believe that the NATURAL, physiological difference between riders is tiny – maybe 1% separates a champion from tenth place. So take a drug that improves performance by, let’s be conservative and say 5%, and that mid-packer still can’t win the race, then you have to wonder about the guy who is winning…?
Meth can be snorted, smoked, swallowed or injected, with addicts often consuming 1,000 times the dose once taken by Wehrmacht soldiers during World War II. The side effects are alarming. Meth weakens the immune system, which leads to eczema, hair loss and so-called "meth mouth," in which the teeth fall out and mucus membranes rot. Meth addicts experience extreme weight loss and develop kidney, stomach and heart problems, which have a nightmarish combined effect: Before and after pictures of meth addicts show that they come to look like living corpses within an extremely short span of time.