Melatonin receptor agonists shorten the time it takes to fall asleep and can prolong total sleep time. Sleep architecture is apparently not altered by melatonin administration, writes Prof. Dieter Steinhilber. Melatonin does not exert a classic hypnotic effect like benzodiazepines or H1 antihistamines, but acts as a hormone that shifts the circadian phase depending on when it is taken.
Whether melatonin has direct hypnotic effects is controversial, but it appears to increase the ability to fall asleep. So far, neither animal studies nor clinical trials have shown any evidence of dependence or abuse potential. Melatonin is not approved as a drug in Europe. In the USA, melatonin is sold as a dietary supplement.
Pharmazie in unserer Zeit: Melatonin, Melatonin‐Rezeptor‐Agonisten und Tryptophan als Schlafmittel. Natürlicher Schlaf? (Article in German, we recommend deepl.com for translatation)