Surprising Benefits of Melatonin: Not Just for Sleep! Sometimes we pigeonhole a supplement thinking it can only do one thing. Melatonin is one of those supplements. Melatonin is a hormone, and it is well known for helping people fall asleep and for helping with jet lag. However, this is such a limited view of this important hormone. Here are some benefits, you may not know about.

melatonin spelled out with dice on a chalkboard background


Light pollution has been postulated to increase the incidence of cancer! Melatonin is shut off when there is light. Melatonin inhibits the growth and sometimes the metastasis of experimental cancers of the lung, liver, ovary, pituitary, and prostate as well as melanoma and leukemia!

  • Breast Cancer: Melatonin has been used in the prevention and treatment of breast cancer. Melatonin downregulates estrogen receptors; inhibits estrogen-stimulated, breast cancer growth; and complements the action of antiestrogen drugs (tamoxifen).
  • Lung and Colorectal Cancer: Forty percent of patients with metastatic lung and colorectal cancer, who received intramuscular melatonin, had stabilization of the disease and improved quality of life.
  • Prostate and colon cancer patients have a reduced circadian amplitude of melatonin.


  • Seizures: Melatonin has a tranquilizing effect and stabilizes electrical activity of the central nervous system. It provides anti-seizure activity in animal and human studies. There needs to be more studies before this is widely accepted. However it may have some role as a compliment to traditional treatment in children with intractable seizures.
  • Depression: Melatonin levels tends to be low in people with major depression especially in those with abnormal pituitary adrenal responses to corticosteroids. This means the feedback loop for the stress hormone cortisol to shut off the pituitary gland from stimulating it or the pituitary stops responding. Disturbed melatonin rhythm play a role in depression, rather than low absolute levels at any given time.


The evidence from the last 10 years suggests that melatonin influences the cardiovascular system, and this may be due to its effect on the hypothalamus in the brain, its antioxidant and blood pressure lowering effect, its ability to reduce excitatory neurotransmitters and/or by relaxing smooth muscle in the blood vessels.

  • MI and Arrythmia: Melatonin has potent antioxidant activity and may play a role in reducing the size of damaged tissue in a heart attack, it may suppress the frequency and duration of heart rhythm disturbances.
  • Blood Pressure decreased with melatonin use. There are receptors for melatonin on the blood vessels and melatonin blood pressure lowering may be due to relaxation of smooth muscles in the aortic walls. People with higher blood pressure have low melatonin levels and even a 1 mg dose reduced blood pressure and excitatory neurotransmitters such as adrenaline and norepinephrine.
  • Cholesterol was reduced by 38% in one review study and melatonin also inhibits copper induced oxidation of LDL cholesterol. Oxidized LDL forms plaque and melatonin may decrease the development of hardening of the arteries due to plaque.

Melatonin may cause minor side effects such as headaches, rash, stomach upset, vivid dreams, nightmares or rash. Timing of melatonin dosing is important. Therefore, since taking melatonin in the morning can stimulate tumor growth but, in the evening, it suppresses tumor growth.

Our minds and bodies are complex. You can achieve hormone balance, nutritional sufficiency, and supplementing with high quality supplements can be transformative. Get a better understanding of the use of melatonin and other supplements. Moreover, hormones to improve or maintain your health from a functional medicine physician who is knowledgeable. Sign up for a free, no obligation clarity call to see if a functional medicine approach to your health is right for you.