Also known by these names

  • MLT
  • N-acetyl-5-methoxytryptamine
  • N-acetyl-methoxytryptamine
  • Pineal hormone

Key Points

  • Melatonin is a hormone produced by the pineal gland in the brain.
  • Melatonin is available as a supplement used as a sleep aid.
  • Melatonin has been investigated, either by itself or as an adjuvant to conventional treatments, with several anticancer effects demonstrated. These include inhibition of cancer growth, of metastasis and of angiogenesis.
  • BCCT’s interest in melatonin derives from its possible protection of non-cancer cells from chemotherapy’s effects and its ability to reduce several symptoms associated with cancer, including sleep disruption, surgery-associated anxiety and pain.
  • Melatonin is generally safe with few side effects.
  • Melatonin supplements are widely available.

Melatonin is a hormone produced by the pineal gland in the brain. Melatonin helps regulate sleep and wake cycles. Very small amounts of melatonin are found in fruits, nuts, olive oil and wine. It is also available as a supplement used as a sleep aid.

Treating the Cancer

Working against cancer growth or spread, improving survival, or working with other treatments or therapies to improve their anticancer action

Melatonin has been investigated for anticancer effects, either by itself or as an adjuvant (supplement) to conventional treatments.

Clinical Evidence

  • Melatonin inhibits cancer growth and promotes tumor cell death in cervical cancer, ovarian cancer, colon cancer and head and neck cancers and counteracts metastasis in head and neck cancer.1
  • Tumor response rate was significantly higher in metastatic non-small cell lung cancer patients treated by chemotherapy plus melatonin than in those treated by chemotherapy alone; however, these therapeutic effects were not seen in patients who "had no spiritual sensitivity."2
  • Less aggressive ovarian cancer were seen with higher serum levels of melatonin in clinical studies.3
  • A combined benefit of melatonin with tamoxifen or cisplatin has been seen in both preclinical and small clinical studies.4
  • Higher tumor regression rates and two-year survival were seen in patients concomitantly treated with melatonin than in those treated with chemotherapy alone.5
  • Small to moderately sized studies suggest improvements in survival time:
    • In a study of untreatable advanced solid tumors, the percentage of patients with disease stabilization and the percentage one-year survival were both significantly higher in patients concomitantly treated with melatonin than in those treated with supportive care alone.6
    • Adding melatonin to chemo- and radiotherapy may have synergistic therapeutic effects and increase the survival time in patients with skin cancer.7
    • In patients with metastatic solid tumors, melatonin alone induced a significant increase of disease stabilization and survival time with respect to supportive care alone. Combining subcutaneous low-dose interleukin-2 with melatonin provided a further improvement in the percentage of tumor regressions and of three-year survival compared to melatonin alone.8
    • Adding melatonin to chemotherapy, radiotherapy, supportive care, and palliative care significantly improved outcomes for one-year mortality, complete response, partial response and stable disease in a pooled analysis.9
  • Melatonin Increased survival time in several types of cancer.10

Lab and Animal Evidence

Expand list

Melatonin, Light and Sleep

Melatonin is produced naturally by the pineal gland during the early hours of night, signaling and initiating the transition from wakefulness to sleep. Individuals who experience sleep difficulties may have disrupted melatonin production.

Read more

Managing Side Effects and Promoting Wellness

Managing or relieving side effects or symptoms, reducing treatment toxicity, supporting quality of life or promoting general well-being

Clinical Evidence

Melatonin may improve quality of life by reducing side effects and symptoms. In addressing symptoms commonly associated with cancer and treatments, melatonin has shown these effects:

  • In a small trial of metastatic breast cancer, bedtime melatonin was associated with a significant improvement in a marker of objective sleep quality, sleep fragmentation and quantity, subjective sleep, fatigue severity, global quality of life, and social and cognitive functioning scales.25
  • Melatonin improved sleep, fatigue, social and cognitive functioning and quality of life in breast cancer patients.26
  • Melatonin significantly reduced the risk of depressive symptoms in women with breast cancer during a three-month period after surgery in a small, randomized, controlled trial.27
  • Melatonin reduced the risk of developing depressive symptoms and also increased sleep efficiency perioperatively and total sleep time postoperatively.28
  • Melatonin improved sleep latency, reduced pre-operative anxiety and prevented agitation in a 2018 meta-analysis.29
  • Melatonin is a potential preventive therapy for radiotherapy-induced oral mucositis.30
  • Melatonin significantly reduced occurrences of alopecia (hair loss), anemia, asthenia (weakness or lack of energy), and thrombocytopenia (low platelet levels) in a pooled analysis of patients with solid tumors,31 and cachexia (muscle wasting), asthenia, thrombocytopenia, lymphocytopenia (low lymphocyte count), stomatitis (swelling and sores inside the mouth), cardiotoxicity and neurotoxicity in clinical trials.32
  • However, in cachectic (wasting syndrome) patients with advanced cancer, oral melatonin at night did not improve appetite, weight or quality of life compared with placebo.33

Lab and Animal Evidence

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Reducing Risk

Clinical Evidence

  • A 2018 meta-analysis concluded that melatonin use is associated with lower risk of breast cancer.35

Lab and Animal Evidence

Read more


Melatonin is generally considered safe, although a doctor’s supervision is recommended. Melatonin has a very low toxicity profile and is not associated with significant side effects.39 However, it should be stopped five to seven days before surgery to avoid magnifying the effects of anesthesia.40

Melatonin use at recommended doses typically does not lead to dependency, habituation or a drug hangover, all common issues with many pharmaceutical sleep aids.


Melatonin supplements are widely available and are generally affordably priced.


BCCT does not recommend therapies or doses, but only provides information for patients and providers to consider as part of a complete treatment plan. Patients should discuss therapies with their physicians, as contraindications, interactions and side effects must be evaluated. 

Levels of active ingredients of natural products can vary widely between and even within products. See Quality and Sources of Herbs, Supplements and Other Natural Products.

Dosage recommendations are available from these sources:

Integrative Programs, Protocols and Medical Systems

For more information about programs and protocols, see our Integrative Programs and Protocols page.
  • Programs and protocols
    • Alschuler & Gazella complementary approaches41
      • Brain cancer
      • Breast Cancer
      • Colon cancer
      • Healthy digestion
      • Hormone balance
      • Kidney cancer
      • Leukemia, lymphoma and myeloma
      • Lung cancer
      • Melanoma
      • Ovarian cancer
      • Pancreatic cancer
      • Prostate cancer
      • Soft tissue sarcoma
      • Thyroid cancer
    • Block program42
      • Breast cancer (case study)
      • Improving sleep
      • Immune surveillance terrain modifier
      • Logical coupler with chemotherapy
    • Chang strategies43
    • Lemole, Mehta & McKee protocols44
      • Bladder cancer
      • Breast cancer
      • Colorectal cancer
      • Lung cancer
      • Prostate cancer
    • McKinney protocols45
      • General cancer
      • Breast cancer
      • Carcinoid/neuroendocrine cancer
      • Cervical cancer
      • Colorectal cancer
      • Esophageal cancer
      • Fibrosarcoma
      • Head and neck cancer
      • Kidney cancer
      • Leukemia
      • Liver/gallbladder cancer
      • Lung cancer
      • Lymphoma
      • Multiple myeloma
      • Myelodysplastic syndrome
      • Ovarian cancer
      • Pancreatic cancer
      • Prostate cancer
      • Stomach cancer

Non-cancer Uses of Melatonin

BCCT has not reviewed the effectiveness of this therapy for non-cancer uses.

  • Alzheimer's disease
  • Amyotrophic lateral sclerosis (ALS)
  • Migraine headaches
  • Periodontal disease
  • Protozoan parasitic infections
  • Sleep disturbances due to insomnia, jet lag, shift work and other situations

Written by Nancy Hepp, MS, and reviewed by Laura Pole, RN, MSN, OCNS; most recent update on April 10, 2019. Note: BCCT has not conducted an independent review of research of  melatonin. This summary draws from the Memorial Sloan Kettering Cancer Center’s About Herbs, Mayo Clinic and other sources as noted.

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