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 that 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 cancercolon cancer and head and neck cancers and counteracts metastasis in head and neck cancer.1
  • Overall tumor regression rate and the five-year survival results were higher in metastatic non-small cell lung cancer patients concomitantly treated with melatonin in addition to chemotherapeutic agents.2 Another study found similar results, although these therapeutic effects were not seen in patients who "had no spiritual sensitivity."3
  • Less aggressive ovarian cancer were seen with higher serum levels of melatonin in clinical studies.4
  • A combined benefit of melatonin with tamoxifen or cisplatin has been seen in both preclinical and small clinical studies.5
  • Higher tumor regression rates and two-year survival were seen in patients concomitantly treated with melatonin than in those treated with chemotherapy alone.6
  • 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.7
    • Adding melatonin to chemo- and radiotherapy may have synergistic therapeutic effects and increase the survival time in patients with skin cancer.8
    • 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.9
    • 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.10
  • Melatonin Increased survival time in several types of cancer.11

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.

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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:

  • Reduced frequency of chemotherapy-induced side-effects:26
    • Weakness (asthenia)
    • Low blood platelet count (thrombocytopenia)
    • Inflammation of the mouth and lips (stomatitis)
    • Cardiotoxicity
    • Neurotoxicity
  • elatonin improved sleep latency, reduced pre-operative anxiety and prevented agitation in a 2018 meta-analysis.27
  • Melatonin is a potential preventive therapy for radiotherapy-induced oral mucositis..28
  • Melatonin significantly reduced occurrences of hair loss (alopecia), anemia, weakness or lack of energy (asthenia), and low platelet levels (thrombocytopenia) in a pooled analysis of patients with solid tumors,29 and muscle wasting (cachexia), asthenia, thrombocytopenia, lymphocytopenia (low lymphocyte count), stomatitis (swelling and sores inside the mouth), cardiotoxicity and neurotoxicity in clinical trials.30
  • 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.31
  • Protective effects against kidney damage (nephrotoxicity) caused by different chemotherapy agents such as cyclophosphamide, cisplatin, doxorubicin, methotrexate, oxaliplatin, etoposide and daunorubicin in non-clinical studies.32
  • Breast cancer:
    • Melatonin is associated with a significant improvement in measures of sleep quality, fatigue, global quality of life, and social and cognitive functioning.33
    • 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.34
    • Melatonin reduced the risk of developing depressive symptoms and also increased sleep efficiency perioperatively and total sleep time postoperatively.35
  • Prostate cancer: Melatonin decreased pain scores and tramadol consumption and enhanced sleep quality, sedation scores, and subjective analgesic efficacy during the postoperative period in patients undergoing elective prostatectomy.36

Lab and Animal Evidence

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Reducing Risk

Clinical Evidence

Lab and Animal Evidence

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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.43 However, it should be stopped five to seven days before surgery to avoid magnifying the effects of anesthesia.44

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.

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 August 21, 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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