Heroin is an opioid drug made from morphine, a natural substance taken from the seed pod of the Asian opium poppy plant. Heroin can be a white or brown powder, or a black sticky substance known as black tar heroin.
Heroin is technically considered an opioid not an opiate, since it is chemically manufactured, although molecules from the opium plant are used in the process. Some of heroin’s active ingredient molecules are not found in nature.
Heroin enters the brain rapidly and changes back into morphine. It binds to opioid receptors on cells located in many areas of the brain, especially those involved in feelings of pain and pleasure. Opioid receptors are also located in the brain stem, which controls important processes, such as blood pressure, arousal, and breathing.
Heroin is manufactured from opium poppies cultivated in four primary source areas: South America, Southeast and Southwest Asia, and Mexico. Afghanistan now produces the majority of the world’s heroin, but little or none of the Afghanistan heroin reaches the US. Although 10 years ago, the US got 90% of its heroin from Columbia, today we get 90% of our heroin from Mexico (up from 10% in 2003).