Melatonin is a hormone that your brain naturally produces in response to darkness. Melatonin helps with the timing of your circadian rhythms (24-hour internal clock) and with sleep. Being exposed to light at night can actually block melatonin production. Research suggests that melatonin plays other important roles in the body beyond sleep. However, these effects are not fully understood. Melatonin dietary supplements can be made from animals or microorganisms, but most often they’re made synthetically.
Benefits of Melatonin
Melatonin supplements may help with certain conditions: such as jet lag, delayed sleep-wake phase disorder, some sleep disorders in children, and anxiety before and after surgery.
Jet lag affects people when they travel by air across multiple time zones. With jet lag, you may not feel well overall and you may have disturbed sleep, daytime tiredness, impaired functioning, and digestive problems. Two studies showed that melatonin may be better than a placebo in reducing symptoms of jet lag after westward flights.
Delayed Sleep-Wake Phase Disorder (DSWPD)
People with DSWPD have trouble falling asleep at the usual times and waking up in the morning. They typically have difficulty getting to sleep before 2 to 6 a.m. and would prefer to wake up between 10 a.m. and 1 p.m. Melatonin supplements appear to help with sleep in people with DSWPD, but it’s uncertain whether the benefits outweigh the possible harms. This is based on a clinical practice guideline, and some more recent studies.
Some Sleep Disorders in Children
Sleep problems in children can have undesirable effects on their behavior, daytime functioning, and quality of life. Children with certain conditions, such as atopic dermatitis, asthma, attention-deficit hyperactivity disorder (ADHD), or autism spectrum disorder (ASD), are more prone to sleep problems than other children. Overall, the studies showed that melatonin was better than placebo for improving both the time to fall asleep and total sleep. The effects of melatonin on behavior and daytime functioning, however, weren’t clear because the studies used different ways to measure these outcomes.
Anxiety before and after surgery happens in up to 80 percent of patients. Melatonin supplements appear to be helpful in reducing anxiety before surgery, but it’s unclear if it helps to lower anxiety after surgery. The studies found strong evidence that melatonin is better than placebo at reducing anxiety before surgery. Melatonin supplements may be as effective as standard treatment.
Possible Side Effects and Cautions
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 currently lacking. Some of the mild side effects that were reported in some studies included:
Additionally, if taking melatonin, it is not recommended to use heavy equipment or machinery for a few hours after taking the supplement. If using a melatonin supplement long-term, consulting with your healthcare practitioner is advisable.