L-DOPA
Levodopa, or L-DOPA is an amino acid. In the body of mammals, it is made from Tyrosine in a process named synthesis. It also occurs in different plants. As such it can be used as a dietary supplement. L-Dopa is the precursor to the neurotransmitters dopamine, norepiphedrine and epiphedrine, which are part of a group known as Catecholamines. L-dopa can also be used as a drug for diseases such as Parkinson's disease. The substance used in the drug is usually called Levodopa, and the naturally occurring substance is called L-Dopa.
Swedish scientist Arvid Carlsson first saw that the substance could be used as a drug, in 1957. It was first introduced as Madopar, by Hoffmann-La Roche, in 1973, as a treatment for Parkinson's disease. The WHO has put it on the list of essential medicines. Because the drug has side-effects, when taken for a longer period of time, people often try to replace it witrh other drugs, especially in younger patients.