Melatonin

Melatonin: A Natural Hormone for Sleep, Immunity, and Cellular Health

Melatonin is a hormone naturally produced by the body to help regulate the sleep-wake cycle. Often called the “sleep hormone,” it is secreted by the pineal gland in the brain, primarily in response to darkness. Melatonin levels begin to rise in the evening, peak in the middle of the night, and fall in the early morning hours. This rhythmic pattern helps synchronize the body’s internal clock, known as the circadian rhythm, which governs not only sleep but also hormone release, metabolism, and immune activity.

Melatonin is made from the amino acid tryptophan, which is first converted into serotonin—a neurotransmitter—and then into melatonin through a process that is strongly influenced by light exposure. During daylight hours, melatonin production is naturally suppressed. But in darkness, especially at night, production increases to prepare the body for rest and cellular repair. Beyond the brain, smaller amounts of melatonin are also synthesized in the gastrointestinal tract, retina, bone marrow, and immune cells, where it serves local protective functions.

As we age, melatonin production gradually declines. This natural decrease can be worsened by lifestyle factors such as exposure to artificial light at night (particularly blue light from screens), irregular sleep schedules, chronic stress, and nutritional deficiencies. Signs of melatonin imbalance may include difficulty falling or staying asleep, fatigue, mood changes, weakened immune defenses, and poor adaptation to time zone changes or shift work.

Supplemental melatonin is widely used to support sleep, especially for insomnia, jet lag, and circadian rhythm disturbances. Typical doses range from 0.3 mg to 5 mg taken 30 to 60 minutes before bedtime. For general sleep support, lower doses often work best, closely mimicking natural physiological levels. In more targeted therapeutic protocols, higher doses may be used, particularly under medical supervision. Sustained-release and sublingual formulations are available, as are gummies, tablets, and liquid sprays.

Melatonin’s benefits go far beyond sleep. It acts as a potent antioxidant, helping to neutralize harmful free radicals and reduce oxidative stress throughout the body. This is especially important during sleep, when the body enters a state of cellular repair and detoxification. Melatonin also has significant anti-inflammatory properties, helping to calm overactive immune responses and reduce chronic low-grade inflammation—one of the root drivers of aging and many chronic diseases.

Within the immune system, melatonin helps to balance and regulate immune function. It supports the activity of natural killer (NK) cells, T cells, and other immune cells involved in surveillance and defense. This immune-modulating effect may help the body better respond to infections, reduce autoimmunity in certain cases, and protect against immune exhaustion in chronic disease states. In times of illness or stress, the body’s natural melatonin response is often disrupted, which may explain why sleep, immunity, and healing are so closely linked.

Nutritionally, melatonin production can be supported by eating foods rich in tryptophan (such as turkey, eggs, oats, and pumpkin seeds), as well as foods that contain natural melatonin, including tart cherries, walnuts, tomatoes, and bananas. Adequate intake of cofactors such as magnesium, vitamin B6, and zinc also supports melatonin synthesis. Maintaining healthy light exposure—bright natural light during the day and minimal artificial light at night—is essential for optimal melatonin signaling.

In recent years, scientists have become increasingly interested in melatonin’s broader effects on health, particularly its potential role in cancer prevention and treatment. Research suggests that melatonin may help reduce cancer risk by supporting DNA repair, suppressing inflammation, and enhancing the immune system’s ability to detect and eliminate abnormal cells. It may also interfere with cancer cell growth, slow the formation of new blood vessels that feed tumors, and even enhance the effectiveness of chemotherapy and radiation while protecting healthy tissues. Although melatonin is not a cure or replacement for conventional cancer therapy, it is being studied and used in integrative oncology as a supportive therapy to improve treatment outcomes and quality of life.

Melatonin is a remarkable hormone—gentle, natural, and deeply connected to the body’s rhythms and resilience. Whether supporting sleep, immunity, or long-term cellular health, melatonin plays a quiet but powerful role in helping the body repair, restore, and protect itself each night.