1. Health
You can opt-out at any time. Please refer to our privacy policy for contact information.

Melatonin Side Effects, Safety Concerns


Updated June 25, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Melatonin Side Effects and Safety Concerns, cont'd

Melatonin influences the production of other hormones. It could theoretically interfere with normal sexual development, so it shouldn't be used by children unless they are under the supervision of a healthcare provider. For the same reason, it shouldn't be used by women who are trying to conceive or by pregnant or nursing women. Increased male breast size and reduced sperm count have also been reported. Melatonin may also affect insulin levels.

Melatonin can influence immune function and it's not known how it affects people with autoimmune conditions such as multiple sclerosis, psoriasis, Crohn's disease, rheumatoid arthritis, lupus, and type 1 diabetes.

Melatonin supplements may worsen the symptoms in people with depression, so people with depression should only use melatonin under the supervision of a health care provider. Melatonin is broken down by the liver, so people with liver disease should avoid melatonin.

Possible Drug Interactions

Melatonin may interact with the following drugs:

  • High blood pressure medication
  • Drugs that suppress the immune system, such as cyclosporine
  • Antidepressant medication
  • Corticosteroids (used for inflammatory conditions such as arthritis)
  • Benzodiazepines, such as diazepam (Valium), and other drugs that cause sedation
  • Herbs that cause sleepiness or drowsiness, such as kava kava and valerian
  • The herb St. John's wort


Natural Standard. "Melatonin" Mayoclinic.com. Accessed October 3, 2007.

PDRHealth. "Melatonin" Accessed October 3, 2007.

  1. About.com
  2. Health
  3. Alternative Medicine
  4. Healing Common Conditions
  5. Insomnia
  6. Melatonin - Side Effects, Safety Concerns

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.