From the Guidelines
The safe dosage of melatonin for an adult is typically 3 mg taken at bedtime, which can be titrated up to 15 mg in 3-mg increments if needed. This recommendation is based on the most recent and highest quality study available, which suggests that immediate-release melatonin is effective in treating isolated REM sleep behavior disorder (RBD) in adults 1. The study notes that melatonin binds to the M1 and M2 receptors, suppressing REM sleep motor tone and renormalizing other circadian features of REM sleep.
Some key points to consider when using melatonin include:
- Starting with a low dose of 3 mg and titrating up as needed to minimize potential side effects
- Being aware that melatonin is considered a dietary supplement and may have varying bioavailability and content across different formulations
- Considering the potential for combination therapy with other agents, such as clonazepam, if response to monotherapy is inadequate
- Monitoring for potential side effects, such as headache, dizziness, nausea, or daytime drowsiness, although the study does not provide specific information on the incidence of these side effects with melatonin use.
It's also important to note that the study suggests that melatonin requires a prescription in the European Union and the United Kingdom, but is available over the counter in the United States and Canada 1. However, as with any supplement, it's crucial to purchase melatonin from reputable manufacturers to ensure consistency and quality. If sleep problems persist or worsen, it's essential to consult a healthcare provider to rule out underlying conditions that may require different treatment.
From the FDA Drug Label
PRINCIPAL DISPLAY PANEL - Vitamin Bottle Label Safrel Melatonin 3mg Tablets: The FDA drug label does not answer the question.
From the Research
Safe Dosage of Melatonin for Adults
The safe dosage of melatonin for adults is a topic of ongoing research, with various studies investigating its efficacy and safety.
- According to a systematic review and meta-analysis published in 2022 2, high-dose melatonin (≥10 mg) appears to have a good safety profile, although the evidence is limited and better safety reporting in future long-term trials is needed.
- An integrative review published in 2021 3 found that the effective melatonin doses varied according to each age group, with 1 to 5 mg being the recommended dose for adults.
- A narrative review published in 2023 4 suggested that melatonin at low to moderate dosages (approximately 5-6 mg daily or less) appears safe, although the long-term effects of taking exogenous melatonin have been insufficiently studied.
- A study published in 2022 5 found that high-dose melatonin (5.0 mg) increased sleep duration during nighttime and daytime sleep episodes in older adults.
- A review published in 2017 6 noted that exogenous melatonin supplementation is well tolerated and has no obvious short- or long-term adverse effects, making it a potential alternative treatment for sleep disorders.
Adverse Effects
While melatonin is generally considered safe, some studies have reported adverse effects, including:
- Drowsiness, headache, and dizziness 2
- Mild side effects when taking usual doses 3
- Short-term negative effects that are minimal and resolve at medicine cessation 4
Dosage Recommendations
Based on the available evidence, the recommended dosage of melatonin for adults varies, but a common range is: