It takes only $1,000 worth of ingredients to make $20,000 worth of meth.

As with other amphetamines, tolerance to methamphetamine is not completely understood, but known to be sufficiently complex that it cannot be explained by any single mechanism. The extent of tolerance and the rate at which it develops varies widely between individuals, and even within one person it is highly dependent on dosage, duration of use and frequency of administration. Many cases of narcolepsy were treated with methamphetamine for years without escalating doses or any apparent loss of effect.

Heroin overdose takes the lives of many users each year. It is not a surprise that those who abuse heroin are at an increased risk of death. Their excess mortality rate ranges between six to twenty times their peers who are of the same age and gender and have not abused heroin. The causes of this excess mortality are manifold, including HIV/AIDS, hepatitis and violence. Despite the HIV pandemic among injecting drug users, deaths attributed to overdose remain a major cause of mortality for heroin users, and in many countries is the leading cause of death. Typically, males are the most predominant casualties of a heroin overdose. With around 80% of heroin overdose deaths reported being male.