Endogenous neurohormone, melatonin receptor agonist
Activation of MT1 and MT2 melatonin receptors in the suprachiasmatic nucleus of the hypothalamus, which regulates circadian rhythms and promotes sleep onset and maintenance.
None
Insomnia
Various formulations: immediate-release oral tablets, controlled-release oral tablets, sublingual, and topical
2–10 mg taken nightly, typically 1–2 hours before bedtime.
2–10 mg/day
Hepatic metabolism (CYP1A2); reached peak plasma concentrations ~ 30-60 minutes (dependent on formulation)
Daytime sleepiness, headache, dizziness, fatigue
None reported
None
None
Melatonin is most effective for sleep disturbances related to circadian rhythm disruptions rather than general insomnia. Its benefits can vary in conditions like dementia, Parkinson’s disease (PD), traumatic brain injury (TBI), and neurodevelopmental conditions, where sleep problems often have complex causes. Because melatonin is sold as a supplement, product quality and dosing can be inconsistent, so using trusted brands is important. Monitor older adults closely for increased daytime drowsiness or interactions with other medications.