L-dopa

Chemical, normally produced by the body, which is converted by an enzyme to dopamine in the brain. It is essential for integrated movement of individual muscle groups.

L-dopa is a left-handed isomer of an amino acid C₉H₁₁NO₂. As a treatment, it relieves the rigidity of Parkinson's disease in 60% of sufferers, but may have significant side effects, such as extreme mood changes, hallucinations, and uncontrolled writhing movements. It is often given in combination with other drugs to improve its effectiveness at lower doses.