Melatonin Buyer's Guide

melatonin buyer's guide
What you need to know about melatonin


Melatonin is a hormone secreted by the brain's pineal gland that plays a critical role in sleep. It maintains the human body’s circadian rhythm (the internal body clock) and assists in the regulation of other hormones. The production and release of melatonin increases in the evening with darkness and decreases in the morning with natural light. Melatonin levels in the blood are highest before bedtime and remain elevated for about 12 hours throughout the night before the morning light causes a drop to lower daytime levels. During the shorter days of the winter months, the body may produce melatonin either earlier or later in the day than usual.  

Exposure to artificial light at night or a lack of light during the day will disrupt the body's normal melatonin cycles and block the production of melatonin at night. International travel and late night shift work are known to disrupt melatonin cycles.  

Melatonin also plays a role in the timing and release of female reproductive hormones. It helps determine when a woman first starts menstruating and stops menstruating (menopause), as well as the frequency and duration of menstrual cycles.


The strongest evidence supporting the use of melatonin is for delayed sleep phase syndrome, insomnia in children and the elderly, jet lag, and sleep problems in people with behavioral, developmental, or mental disorders.  

Delayed Sleep Phase Disorder  

Delayed sleep phase disorder is a disruption of the body’s biological clock in which a person’s sleep-wake timing cycle is delayed by 3 to 6 hours. Adults and teens with this sleep disorder have trouble falling asleep before 2 a.m. and have trouble waking up in the morning. Studies show that melatonin may help to decrease the amount of time it takes to fall asleep. [1] In a 2007 clinical practice guideline, the American Academy of Sleep Medicine recommended timed melatonin supplementation for this sleep disorder. [2]  

Insomnia in children and the elderly  

Research indicates that melatonin may benefit children and the elderly with insomnia. [1]  

Jet Lag  

Jet lag is caused by rapid travel across several time zones. Its symptoms include disturbed sleep, daytime fatigue, indigestion and a general feeling of discomfort.  

According to its 2007 clinical practice guidelines, the American Academy of Sleep Medicine supports using melatonin to reduce jet lag symptoms and improve sleep after traveling across more than one time zone. [2]  

Sleeping problems in children with autism and intellectual disabilities  

Children and adolescents with intellectual disabilities, autism, and other central nervous system disorders may benefit from melatonin. It may be helpful for disturbed sleep-wake cycles and for decreasing the time it takes to fall asleep. [2]  

Insomnia in healthy people  

Some people who have insomnia appear to have lower melatonin levels. Supplementing with melatonin may help them sleep. Evidence suggests that melatonin decreases the time it takes to fall asleep, as well as improves sleep quality and sleep duration. Melatonin may also be beneficial for daytime sleep. [1]  

Shift Work Disorder  

People who work afternoon to nighttime or nighttime to early morning hours may be affected by shift work disorder. Melatonin may improve daytime sleep quality and duration. The American Academy of Sleep Medicine recommends taking melatonin prior to daytime sleep for night shift workers with shift work disorder to enhance daytime sleep. [2]  

Melatonin may also possibly be effective for: [6]  

  • Cluster headaches (10 mg per night). 
  • Low blood platelets (thrombocytopenia). 
  • Improving the effectiveness of certain cancer medications used to fight tumors in the breast, lung, kidney, liver, pancreas, stomach, colon, prostate, and decreasing some side effects of cancer treatment. 
  • Decreasing symptoms of a movement disorder called tardive dyskinesia (TD). 
  • Helping decrease symptoms in people who are quitting smoking. 
  • Melatonin seems to reduce anxiety, restlessness, irritability, depression, and cigarette craving. A reduction of these symptoms occurs over the next 10 hours when a single oral dose of 0.3 mg of melatonin is taken 3.5 hours after stopping cigarettes. 
  • Helping strengthen the immune system. Preliminary evidence suggests this due to melatonin’s strong antioxidant effects. [5] 
  • Although there is less scientific evidence supporting the effectiveness, some people use melatonin for Alzheimer’s disease, ringing in the ears, depression, chronic fatigue syndrome (CFS), fibromyalgia, migraine and other headaches, irritable bowel syndrome (IBS), bone loss (osteoporosis), epilepsy, insomnia due to beta-blockers (high blood pressure medication),menopause, birth control and an anti-aging agent. [6]  

Side Effects  

Side effects of melatonin are uncommon but can include drowsiness, headache, dizziness, or nausea. There have been no reports of significant side effects of melatonin in children. [2]  


[1] [2] [3] [4] [5] [6]


Melatonin supplements are available in dosages ranging from 1 milligram to 10 milligrams. A 10 milligram dosage is generally considered "maximum strength". It is recommended that consumers test their tolerance for melatonin with a 1 or 3 milligram dosage before moving on to the higher dosages. 

Rapid Release/Fast Dissolve

Melatonin supplements are available in dosages ranging from 1 milligram to 10 milligrams. A 10 milligram dosage is generally considered "maximum strength". It is recommended that consumers test their tolerance for melatonin with a 1 or 3 milligram dosage before moving on to the higher dosages. 

Extended Release

Some melatonin users report that while melatonin does help them to get to sleep, it does not help them stay asleep. After a few hours of sleep, they wake up again and struggle with the same restlessness. Time release or controlled release formulations solve this problem by allowing for a gradual release of the active ingredient over a 4-6 hour period.

Sleep Formulas

Melatonin can also be combined with other ingredients to create advanced sleep-inducing formulas. The most common supplementary ingredients found in these advanced formulations are calcium, magnesium, theanine and valerian root. When ingested together, calcium and magnesium can calm nerves and induce muscle relaxation. Theanine is an amino acid derivative of glutamine found in green tea which can contribute to a calm mental state. Valerian root is an herbal supplement known to have a sedative effect. Formulations with a combination of these ingredients can be more effective than melatonin alone for some individuals. 

NHS Choices Sleep Guide: The National Health Service's online information guide on conditions, treatment, local services and healthy living. National Sleep Foundation: An independent, non-profit organization in the USA whose objectives are to improve public health and safety by achieving understanding of sleep and sleep disorders, and to support sleep-related education, research and advocacy. Royal College of Psychiatrists: The professional medical body responsible for supporting psychiatrists throughout their careers, from training through to retirement, and in setting and raising standards of psychiatry in the United Kingdom. National Health Service, Sleep Self-Assessment: Take this short assessment, get a sleep score and get some practical tips and advice on what to do next. In association with Sleepio, the online cognitive behaviour therapy programme designed to help sleep problems. A sleep health information resource by the American Academy of Sleep Medicine. NHS Melatonin Medicine Guide: The National Health Service’s online source for comprehensive information about medicines, including known possible side effects, interactions and dosages.