Report on Melatonin Side Effects and Usage


Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of cautions that you should be aware of before using Melatonin (known chemically as N-acetyl-5-methoxytryptamine
). These are referred to as drug/herb interactions.

Warning 1 – Contraindications: Pregnancy and lactation (breast-feeding)

Warning 2 – Benzodiazepines: Melatonin may increase the anxiolytic or anxiety relieving effects of benzodiazepines, use cautiously.

Warning 3 – DHEA: Melatonin may decrease cytokine production, the proteins that serve to regulate the immune system. Experts recommend avoiding concurrent use.

Warning 4 – Magnesium: Using Melatonin while taking magnesium supplements increases inhibition of NMDA (N-methyl-D-aspartate) receptors in the brain. These receptors play a part in memory and your ability to learn new things. Experts recommend avoiding concurrent use.

Warning 5 – Zinc: Using Melatonin while taking a zinc supplement increases inhibition of NMDA (N-methyl-D-aspartate) receptors in the brain. These receptors play a part in memory and your ability to learn new things. Experts recommend avoiding concurrent use.

Warning 6 – Orthostatic intolerance: Using Melatonin may exacerbate symptoms by reducing nerve activity in those with orthostatic intolerance.

Warning 7 – Auto-immune disorders: Melatonin supplementation may exacerbate symptoms due to immunomodulation.

Warning 8 – Succinylcholine: This herb increases the blocking properties of succinylcholine. Experts recommend avoiding concurrent use.

Warning 9 – Drug interactions: There is some evidence to suggest that melatonin may interact with various medications, including, blood-thinning medications (anticoagulants), immunosuppressants, diabetes medications, cerebral stimulants, and birth control pills.

Used as a natural health remedy: melatonin is used internally for these benefits:

  • ADHD – Attention Deficit Hyperactivity Disorder
  • Aid in fighting cancer
  • Anti-aging
  • Decrease symptoms of tardive dyskinesia (TD), a movement disorder
  • Decrease the amount of cholesterol produced in the gallbladder
  • Decrease withdrawal symptoms in people who are quitting smoking
  • Improve symptoms of Periodic Limb Movement Disorder
  • Increased libido
  • Preventing the depression associated with the menopause
  • Preventive treatment for migraines and cluster headaches
  • Protection from radiation
  • Reduce anxiety before surgery
  • Reduce delirium
  • Reduce depression
  • Reduce insomnia
  • Reduce sensitivity to sunlight
  • Reduce tinnitus
  • Relieve symptoms of benzodiazepine withdrawal
  • Relieve symptoms of IBS – Irritable Bowel Syndrome
  • SAD – Seasonal Affective Disorder
  • Weight loss

Melatonin has been found to improve the effectiveness of certain cancer medications used to fight tumors in the breast, lung, kidney, liver, pancreas, stomach, colon, prostate, and decreases some of the side effects of cancer treatment.

Side Effects of Melatonin

There are no major or severe side effects with this supplement. However, side effects may show up when using Melatonin at high doses. These include:

  1. sleepiness, if taken during the day
  2. headache
  3. “heavy-head” feeling
  4. stomach discomfort, abdominal cramps
  5. depression
  6. feeling hung over
  7. vivid dreams or nightmares
  8. nausea and vomiting
  9. next-day grogginess
  10. irritability
  11. hormone fluctuations
  12. hypothermia
  13. dizziness

The long-term effects of melatonin have not been well studied. Other side effects may also occur when using Melatonin. (See form below)

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Return to the Herb List.

For questions and answers about the side effects of herbs see the Herb Forum

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