I went to the GP to talk to him about some issues and he gave me melatonin to help me fall asleep, I've taken this before when I was about 6 years old and can't really remember if it had much effect.

Has anyone else used melatonin before?

Melatonin is a hormone produced in the brain by the pineal gland, from the amino acid tryptophan. The synthesis and release of melatonin are stimulated by darkness and suppressed by light, suggesting the involvement of melatonin in circadian rhythm and regulation of diverse body functions. Levels of melatonin in the blood are highest prior to bedtime.