Melatonin typically lasts in the body for about four to five hours after ingestion. Its half-life-the time it takes for half of the melatonin dose to be eliminated-is generally between 20 and 50 minutes, meaning melatonin levels drop significantly within that timeframe but can remain detectable for several hours

. Key points about melatonin duration:

• Melatonin levels peak roughly within 30 to 60 minutes after taking a dose, and then gradually decline

• The total time melatonin stays active in your system is about 4 to 5 hours on average, though some sources note it can last up to 10 hours depending on dose and formulation

• Extended-release melatonin formulations may last longer and can cause drowsiness upon waking if a full night's sleep is not obtained

• Individual factors such as age, health, metabolism, dose, and whether the supplement is immediate- or extended-release influence how long melatonin lasts

Because melatonin is fast-acting but relatively short-lived, it is recommended to take it about 30 to 60 minutes before bedtime to align with its peak effectiveness

. In summary, melatonin’s effects generally last for about 4 to 5 hours, with its half-life ranging from 20 to 50 minutes, but this can vary based on formulation and individual factors.