Reviewed on 8/10/2021

What Is Melatonin and How Does It Work?

Melatonin is a hormone produced by the pineal gland, which regulates the sleep cycle.

Melatonin can be used in treatment for Alzheimer's disease, benzodiazepine or nicotine withdrawal, cancer (adjunctive treatment), headache (prevention), insomnia, jet lag, shift-work disorder, sleep disorders, shortage of blood platelets (thrombocytopenia) (chemo-induced), winter depression, and involuntary muscle movements (tardive dyskinesia).

Melatonin is effective in circadian rhythm sleep disorders and helpful for sleep-wake cycle disorders. Research is continuing.

Melatonin is available under the following different brand names: N-acetyl-5-methoxytryptamine, pineal hormone melatonin.

What Are Dosages of Melatonin?

Dosages of Melatonin:

  • 0.125 mg
  • 0.3 mg
  • 0.5 mg
  • 2 mg controlled release
  • 3 mg
  • 5 mg
  • 10-50 mg

Dosing Considerations

Benzodiazepine Withdrawal in Elderly with Insomnia

  • 2 mg controlled release taken orally at night for up to 6 months; taper dose over 6 weeks

Cancer, Adjunctive Therapy

  • 10-50 mg taken orally daily

Cluster Headache, Prevention

  • 10 mg taken orally at night

Migraine Headache

  • 3 mg taken orally at night


  • 3-5 mg taken orally at night

Difficulty falling asleep

  • 5 mg taken orally 3-4 hours before sleep period x 4 weeks

Difficulty maintaining sleep

  • Use controlled release formulation

Thrombocytopenia, Chemo-related

  • 20 mg taken orally at night

Jet Lag

  • 0.5-5 mg taken orally at night


  • Preflight, early evening dose followed by bedtime dosing x 4 days


  • Treat at bedtime x 4 days when in the new time zone

Chronic Fatigue Syndrome

  • 5 mg taken orally at night

Nicotine Withdrawal

  • 0.3 mg taken orally 3.5 hours after stopping smoking

Winter Depression

  • 0.125 mg taken orally twice daily

Premedication for Surgery

  • 0.5 mg/kg sublingually

Tardive Dyskinesia

  • 10 mg controlled-release taken orally once/day

Sleep Disorders (Orphan)

  • Treatment of circadian rhythm sleep disorders in blind people without light perception

Encephalopathy (Orphan)

Smith-Magenis Syndrome (Orphan)

  • Orphan designation for the treatment of Smith-Magenis syndrome in combination with beta-blocker


Sleep Disorders: Foods That Help Sleep or Keep You Awake See Slideshow

What Are Side Effects Associated with Using Melatonin?

Common Side effects of Melatonin include:

  • abdominal cramps
  • alertness decreased
  • circadian rhythm disruption
  • daytime fatigue
  • depression (temporary)
  • dizziness
  • drowsiness
  • unease or dissatisfaction (dysphoria) in depressed patients
  • headache
  • irritability

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Melatonin?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Serious Interactions of melatonin include:

  • sodium oxybate

Melatonin has moderate interactions with at least 221 different drugs.

Mild interactions of melatonin include:

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

What Are Warnings and Precautions for Melatonin?


  • This medication contains melatonin
  • Do not take N-acetyl-5-methoxytryptamine or Pineal Hormone Melatonin if you are allergic to melatonin or any ingredients contained in this drug
  • Keep out of reach of children
  • In case of overdose, get medical help or contact a Poison Control Center immediately


Effects of Drug Abuse

  • No information available

Short-Term Effects

  • No information available

Long-Term Effects

  • No information available


  • Uses in patients under 20 years old, or with depression, hypertension, impaired liver function or seizure disorder

Pregnancy and Lactation

  • Avoid use in pregnancy or if lactating


What is insomnia? See Answer
Medscape. Melatonin.

Health Solutions From Our Sponsors