Scientific Evidence for Daily Melatonin Supplementation: What Studies Show
Written by Dr. Louis Michaelos, Ophthalmologist & Founder of MacuRest | Last reviewed May 2026
Meta-analyses covering tens of thousands of participants consistently show melatonin improves sleep onset latency, total sleep time, and sleep quality — with an excellent safety profile for long-term use. Emerging research also links daily melatonin to reduced AMD progression risk.
What the Research Shows on Sleep
Multiple systematic reviews and meta-analyses have evaluated melatonin for sleep. A comprehensive 2013 meta-analysis published in PLOS ONE covering 19 studies and 1,683 participants found that melatonin significantly reduced sleep onset latency (time to fall asleep), increased total sleep time, and improved overall sleep quality compared to placebo — with no serious adverse events reported.
A subsequent Cochrane-affiliated review confirmed these findings across diverse populations including older adults, shift workers, and people with jet lag. The evidence base for melatonin as a sleep support supplement is among the most robust of any supplement ingredient.
What the Research Shows on Eye Health
More recent research has drawn attention to melatonin's role in retinal health. A 2024 study in JAMA Ophthalmology analyzed over 100,000 patient records and found melatonin users had significantly lower rates of AMD progression to advanced stages. The retina produces its own melatonin independently and uses it to regulate the overnight photoreceptor repair cycle — a process that is progressively impaired in AMD.
Safety Profile
Melatonin is one of the most extensively studied supplements in adults. At doses of 0.5–10mg, it is generally well tolerated, with mild and transient side effects (drowsiness, headache) reported in a small percentage of users. The NIH National Center for Complementary and Integrative Health considers melatonin safe for short- and long-term use in most adults. MacuRest uses a 5mg dose — within the well-studied range — taken with dinner as part of an evening macular health routine.
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Frequently Asked Questions
Is daily melatonin supplementation safe long-term?
Yes, according to the NIH National Center for Complementary and Integrative Health. Melatonin at doses of 0.5–10mg is generally well tolerated with a mild, transient side effect profile. Large meta-analyses covering thousands of participants have found no serious adverse events. MacuRest uses 5mg nightly, within the well-studied range.
What does research show about melatonin for sleep?
A PLOS ONE meta-analysis of 19 studies and 1,683 participants found melatonin significantly reduced sleep onset latency, increased total sleep time, and improved overall sleep quality vs. placebo, with no serious adverse events. Cochrane-affiliated reviews have confirmed these findings across diverse adult populations including older adults.
Does melatonin interact with other medications?
Melatonin can interact with blood thinners, immunosuppressants, diabetes medications, and some sedatives. Always inform your physician and pharmacist of any supplements you take. If you are on prescription medications, discuss melatonin supplementation with your doctor before starting.
Can I take melatonin every night?
Yes — melatonin is non-habit-forming and does not cause dependence. The NIH considers it safe for long-term nightly use in most adults. MacuRest is designed to be taken every evening with dinner as part of a consistent macular health routine.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.