Is it safe to take melatonin every night?
For healthy adults, melatonin is safe with short-term use, but as a sleep aid for chronic insomnia it works considerably less well than standard sleep medications; pregnant women, breastfeeding women and children outside a medical indication are better off avoiding it.
Short-term melatonin use in adults is relatively well studied. The side effects reported in randomised trials are mild -- think dizziness, headache, nausea and daytime sleepiness. They are comparable to what people report with a placebo, and serious adverse effects have not been identified in the available randomised trials1.
Daily long-term use in adults shows a similar picture: side effects remain mild and are no greater than with placebo. Nevertheless, the volume of long-term data is considerably smaller than for short-term use, which warrants caution. At high doses there is insufficient evidence to guarantee safety1,2. In older adults, residual daytime sedation is a real risk, even at low doses3.
For pregnant women, breastfeeding women, children and adolescents outside specific medical indications, melatonin is explicitly discouraged or at least insufficiently studied. There are simply too few human safety studies available to properly assess risks for the mother, the child or the developing adolescent1.
A practical point of concern is that melatonin is an unregulated supplement in many countries. The actual dose in a product can differ considerably from what is stated on the label, making dosing unpredictable.
As a sleep aid for chronic insomnia, melatonin scores substantially worse than common agents such as benzodiazepines, zolpidem or orexin receptor antagonists in large network meta-analyses. It has some effect on sleep onset latency, but the clinical benefit in adults with chronic insomnia is limited4,5. An exception is prolonged-release melatonin in children with autism spectrum disorder: after 52 weeks, studies showed significant improvements in sleep duration and sleep onset latency, with fatigue (5.3%) and mood swings (3.2%) as the main side effects6.
All claims are based on one primary review (PMID 26692007) and two network meta-analyses (PMID 35843245, 36701954), supplemented by a study in older adults (PMID 27751669), an RCT in children with autism (PMID 30132686) and a review with a commercial conflict of interest (PMID 36235587). The evidence base for long-term safety is moderate to limited.
How much melatonin should you take to sleep better?
For most adults, 4 mg appears to have the greatest effect, but it should be taken 2 to 3 hours before bedtime; if you are older than 55, the extended-release formulation (2 mg) is the only one officially recommended.
Does melatonin as a supplement really work for better sleep in older age?
For older people with sleep complaints, particularly early-morning awakening, melatonin offers a modest but real benefit. The effect varies by person and complaint, the optimal dose is unclear, so start low and discuss long-term use with your doctor.
Are sleeping pills harmful in the long term?
Long-term use of classic sleeping pills increases the risk of dependence, cognitive decline, and impaired driving ability. Therefore, do not use them for longer than two to four weeks, and discuss alternatives with your doctor if you are already a long-term user.
Is it a problem that I often wake up during the night?
Waking up occasionally is normal, but if it happens frequently and affects you during the day, there may be an underlying cause such as sleep apnea or PTSD. In that case, have it checked out.
How dangerous is sleep apnoea?
Untreated sleep apnoea substantially increases the risk of stroke, heart failure and premature death. If you suspect that you or someone around you has it, a diagnosis and treatment are genuinely worthwhile.
Does taking glycine help you sleep better?
Glycine shows tentatively positive signals, but the evidence is thin and the only direct human study comes from the manufacturer itself. Anyone who wants to try it would be wise to view it as a complement to good sleep habits, not a replacement.