Melatonin supplements appear to be helpful in reducing anxiety before surgery, but it’s unclear if they help to lower anxiety after surgery.
- A 2020 review looked at 27 studies of melatonin for treating anxiety before surgery, anxiety after surgery, or both. Twenty-four of the studies compared melatonin with placebo, and 11 compared it with a benzodiazepine antianxiety medicine. Based on evidence from 18 studies, melatonin probably reduces anxiety before surgery, when compared to a placebo. Melatonin might also reduce anxiety after surgery to a small extent, but the evidence for this was of lower quality and came from a smaller number of studies (seven for anxiety immediately after surgery, two for delayed anxiety). The effects of melatonin on anxiety may be similar to those of benzodiazepines before surgery (based on seven studies) and immediately after surgery (three studies).
Safety
For melatonin supplements, particularly at doses higher than what the body normally produces, there’s not enough information yet about possible side effects to have a clear picture of overall safety. Short-term use of melatonin supplements appears to be safe for most people, but information on the long-term safety of supplementing with melatonin is lacking.
Also keep in mind:
Interactions With Medicines
- As with all dietary supplements, people who are taking medicine should consult their health care providers before using melatonin. In particular, people with epilepsy and those taking blood thinner medications need to be under medical supervision when taking melatonin supplements.
Possible Allergic Reaction Risk
- There may be a risk of allergic reactions to melatonin supplements.
Safety Concerns During Pregnancy or While Breastfeeding
- There’s been a lack of research on the safety of melatonin use during pregnancy or while breastfeeding.
Safety Concerns for Older People
- The 2015 guidelines by the American Academy of Sleep Medicine recommend against melatonin use by people with dementia.
- Melatonin may stay active in older people longer than in younger people and cause daytime drowsiness.
Melatonin Is Regulated as a Dietary Supplement
- In the United States, melatonin is considered a dietary supplement. This means that it’s regulated less strictly by the Food and Drug Administration (FDA) than a prescription or over-the-counter drug would be. In several other countries, melatonin is available only with a prescription and is considered a drug.
Products May Not Contain What’s Listed on the Label
- Some melatonin supplements may not contain what’s listed on the product label. A 2017 study tested 31 different melatonin supplements bought from grocery stores and pharmacies. For most of the supplements, the amount of melatonin in the product didn’t match what was listed on the product label. Also, 26 percent of the supplements contained serotonin, a hormone that can have harmful effects even at relatively low levels.
Visit the NCCIH website for more information on melatonin.
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