Quiz: Is Taking Melatonin Every Night Harmful?

Melatonin is a hormone produced in the pineal gland, a pea-sized gland located in the brain, that plays a role in sleep and circadian rhythms.

The body naturally produces more melatonin at night which helps people fall asleep, and lower levels in the morning when people wake up and are exposed to light. Melatonin levels decline as people age.

Melatonin supplements are usually marketed as a sleep aid without the side effects that can accompany prescription and over-the-counter (OTC) sleep aids. Melatonin is used for:

• Insomnia
• Jet lag
• Shift work disorder
• Sleep-wake cycle disturbances
• Circadian rhythm sleep disorders in the blind
• Delayed sleep-wake phase sleep disorder
• Anxiety before and after surgery

Melatonin supplements are available over-the-counter (OTC) without a prescription and common doses range from 0.1 to 10 milligrams, though 0.5 to 5 milligrams are usually considered safe for typical use in healthy adults. Two to three milligrams are usually considered an appropriate initial dose.

Melatonin dosage is not one-size-fits all. Dosing and response can vary based on a person's age, gender, the time the supplement is taken, a person's sleep problems, and other underlying health issues.

Melatonin can be used safely by most adults for occasional insomnia, but it should not be taken indefinitely. If taking melatonin seems to help, it may be taken every night for up to one to two months.

More research is needed on the effects of melatonin in children. Children may be more susceptible to the effects of melatonin on reproductive hormones. While research is conflicting, some studies have shown melatonin to be associated with delays in puberty, irregular menstruation, and overproduction of the hormone prolactin. Melatonin can also decrease blood pressure or blood glucose levels.

Consult your child's pediatrician before giving them melatonin.

Just because melatonin supplements are marketed as "natural" sleep aids, it does not mean they do not cause any side effects. Side effects of over-the-counter melatonin supplements are uncommon and may include:

• Sleepiness
• Dizziness
• Headache
• Nausea
• Confusion
• Fragmented sleep

With melatonin, less is often better, and excess melatonin can be harmful. Symptoms of excess melatonin may include:

• Hypotension (low blood pressure)
• Hypertension (high blood pressure)
• Vomiting
• Worsening of alopecia areata (an autoimmune disorder causing hair loss)
• May cause depression in people who have depression or who are predisposed to it
• Increased seizures in patients with epilepsy

Melatonin supplements are generally safe for use as directed but there can be some risks to taking it, such as:

• Benzodiazepines
• Blood thinners
• Seizure medications

• Melatonin products may not contain what's listed on the label
• There can be a wide variety in the ingredients, dose, preparation, and purity of melatonin supplements which may result in a significantly different impact on the body, even for the same dosage
• Look for the United States Pharmacopeial Convention Verified labels to find reliable formulations

Melatonin is not appropriate for use by everyone. People who should not use melatonin include those who:

• Have an autoimmune disorder
• Have a seizure disorder
• Have clinical depression
• Have diabetes
• High blood pressure
• Are pregnant or breastfeeding
• Take certain hypertension medications