What is melatonin, and why is it vital for health?
Melatonin is widely known as a sleep aid, but its benefits extend far beyond regulating your sleep-wake cycle. This hormone supports antioxidant defense, immune function, and mitochondrial health, making it a key player in longevity and vitality. This article dives into melatonin’s diverse roles, optimal use, and emerging research to help you harness its potential.

TL;DR
Melatonin is far more than a sleep hormone. It regulates circadian rhythms, acts as a potent antioxidant, and supports immune and mitochondrial health. Produced in the pineal gland, gut, and mitochondria, it declines with age. Natural sources (phytomelatonin) may offer added benefits. Explore melatonin’s science, dosing, and health impacts below.

Science Snapshot: Melatonin’s Core Mechanisms

• Hormone Function: Regulates sleep-wake cycles via MT1/MT2 receptors, signaling nighttime.

• Antioxidant Power: Neutralizes 10+ reactive oxygen species (ROS), outperforming vitamins C and E.

• Immune Regulation: Modulates cytokines, T-cell activation, and inflammation control.

• Mitochondrial Support: Enhances energy production and protects against oxidative stress.

• Production Sites: Pineal gland (nighttime), gut (400x more), mitochondria (local repair).

• Natural Sources: Tart cherries, walnuts, grapes contain phytomelatonin with flavonoids.

What Is Melatonin?

Melatonin is a hormone best known for managing the body’s sleep-wake cycle. It’s secreted primarily by the pineal gland in response to darkness, earning it the nickname “the darkness hormone.” But melatonin is also found in other tissues and plays roles far beyond sleep. It acts as a powerful antioxidant, modulates immune function, protects DNA, and helps regulate mitochondrial performance. It binds to melatonin receptors (MT1 and MT2) found throughout the body, helping coordinate peripheral circadian clocks and tissue-specific functions. These diverse roles connect to its impact on cellular health and longevity.

Where Is Melatonin Produced in the Body?

Melatonin isn’t made in just one place. The pineal gland is the primary nighttime source, releasing it into the bloodstream in response to light-dark cues. But astonishingly, the gut produces around 400 times more melatonin than the pineal gland—though it doesn’t follow circadian rhythms. Even mitochondria, the energy hubs of our cells, can produce melatonin locally to buffer oxidative stress. These decentralized sources suggest melatonin is critical for local cell regulation, repair, and redox balance, far beyond its traditional role in sleep. This multi-site production is explored further.

How Does Melatonin Support Sleep?

Melatonin's central role in sleep involves lowering core body temperature and signaling the onset of night. It helps the body shift into rest mode by synchronising the internal circadian rhythm. Supplementation has been shown to support people with insomnia, jet lag, delayed sleep phase syndrome, and disrupted sleep due to shift work or age. Timing is key—those sensitive to caffeine may benefit from taking melatonin 60–90 minutes before sleep, while faster metabolizers may benefit from a dose just before bed. Starting with 0.3 mg is often effective. Proper dosing strategies are detailed below.

What Are Melatonin’s Antioxidant and Immune Benefits?

Melatonin is one of the most versatile antioxidants in human biology. It neutralizes at least 10 different reactive oxygen and nitrogen species, outperforming conventional antioxidants like vitamins C and E. It stimulates the body’s own defences by boosting enzymes like superoxide dismutase and glutathione peroxidase. Melatonin also plays a role in the immune system by influencing cytokine production, T-cell activation, and inflammation regulation. These protective roles make melatonin crucial for cellular health, especially under oxidative or inflammatory stress. Its immune and antioxidant effects tie into potential cancer research applications.

How Does Melatonin Benefit Gut and Mitochondrial Health?

Gut melatonin may help regulate intestinal motility, repair gut lining cells, and protect against oxidative damage. It’s produced independently of the light-dark cycle and may play a role in modulating the gut-brain axis. Meanwhile, mitochondrial melatonin helps preserve mitochondrial integrity, energy production, and biogenesis. It’s thought to reduce the burden of reactive oxygen species (ROS) generated during ATP production, potentially improving energy, endurance, and healthy ageing. Together, gut and mitochondrial melatonin act as local, targeted protectors. These benefits link to age-related health challenges.

Why Does Melatonin Decline with Age?

From age 20 onward, melatonin levels decline steadily. This reduction may impair sleep, immune resilience, and tissue repair. Nighttime exposure to artificial light worsens this decline by suppressing melatonin release. Chronodisruption—disruption of natural circadian cues—has been linked to obesity, neurodegeneration, cardiovascular disease, and some cancers. For those over 50, supplementation with physiological doses (0.3–0.5 mg) may help re-align body clocks, improve sleep architecture, and restore regenerative processes governed by the night-time repair cycle. 

Synthetic vs. Phytomelatonin: What’s the Difference?

Synthetic melatonin is chemically identical to endogenous melatonin, but phytomelatonin (from plants) is accompanied by additional bioactives such as flavonoids and phenolics. These may enhance absorption or create synergistic antioxidant effects. Although dietary melatonin sources like tart cherries and walnuts contain only trace amounts, plant-based melatonin supplements derived from herbs or algae have shown promising results in animal and human studies. Early data suggests phytomelatonin may be more bioavailable and require lower dosing, but clinical research is still evolving. Dosing guidance is provided below.

Can Melatonin Play a Role in Cancer Prevention?

Melatonin is under investigation for its anti-tumour potential, particularly in hormone-sensitive cancers. It may inhibit tumor growth by limiting blood supply, improving immune surveillance, and reducing oxidative DNA damage. Epidemiological studies show that chronic night shift workers—who experience melatonin suppression—have higher cancer risk. In some clinical studies, high-dose melatonin (up to 200 mg/day) has been used as an adjuvant in cancer therapy. However, such interventions are experimental and should only be pursued under medical supervision. 

How Should You Use Melatonin: Dosage and Timing?

The human body naturally produces between 0.1 and 0.9 mg of melatonin per night. For most adults, starting with 0.3 mg is effective and well tolerated. Those with difficulty falling asleep may benefit from taking it 60–90 minutes before bed, while those with nighttime wakefulness might take it at bedtime. Slow metabolizers (who are also caffeine-sensitive) should start low to avoid morning grogginess. Fast metabolizers may need higher doses. Melatonin is often used in higher doses for short-term jet lag support or experimental medical protocols. Always adjust based on individual response and consult a doctor for long-term use.

What Are Melatonin’s Interactions and Safety Precautions?

Melatonin is generally safe when taken appropriately, but it can interact with:

• Blood thinners (e.g., warfarin)

• Hypoglycemics

• Blood pressure medications

• CYP1A2-inhibiting drugs (e.g., fluvoxamine)

Precautions:

• Melatonin is not typically recommended for pregnant or breastfeeding women, unless medically supervised.

• Some people experience vivid dreams or morning drowsiness, particularly at higher doses.

• While there's no evidence of dependency, discontinuation may result in transient rebound sleep disruption.

Always consult a healthcare provider if you’re taking medication or managing chronic conditions.

Conclusion: Melatonin’s Role in Longevity

Melatonin is an incredibly powerful molecule—not just for sleep, but for systemic repair, antioxidant defence, mitochondrial support, and immune regulation. As our levels decline with age, strategic supplementation may offer broad benefits. Its production in multiple body systems highlights how deeply embedded it is in maintaining balance and restoring function. Whether you’re navigating jet lag, stress, inflammation, or the challenges of aging, melatonin deserves serious attention as a tool for optimising healthspan.

Longevity Checklist:

• Take 0.3–0.5 mg melatonin 60–90 minutes before bed to support sleep.

• Reduce nighttime light exposure to preserve natural melatonin production.

• Explore phytomelatonin for potential enhanced bioavailability.

• Consult a healthcare provider for high-dose or long-term use.

These interventions work together to enhance circadian health, cellular repair, and overall vitality.

FAQ

1. Can I get enough melatonin from food alone?
   No. While foods like tart cherries, walnuts, and grapes contain small amounts, the dose is far below therapeutic or physiological levels. Supplementation is necessary for meaningful effects.

2. What’s the ideal melatonin dose for adults?
   For general sleep support, 0.3–0.5 mg is typically effective. Higher doses (e.g., 3 mg) may be used short-term for jet lag or specific conditions.

3. Is melatonin safe for long-term use?
   Yes, when used in physiological doses (0.3–0.5 mg). There’s no evidence of dependency or withdrawal. Consult a doctor if taking medications.

4. How does phytomelatonin compare to synthetic melatonin?
   Phytomelatonin includes plant compounds that may improve bioavailability, while synthetic melatonin is pure and well-studied. Both are effective for sleep.

5. Can melatonin help with cancer or inflammation?
   Emerging studies suggest high-dose melatonin may reduce tumor growth and inflammation, but it should only be used under medical supervision.

6. Is Melatonin available in the UK to buy/Unfortunately Melatonin in the UK is only available to purchase via a prescription, but we do have a product called PM sleep dust that activate various sleep pathways that can help with sleep you can find that on our website.

Glossary

• Melatonin: A hormone that regulates the body’s internal clock, promotes sleep, and supports antioxidant and immune functions.

• Phytomelatonin: Melatonin derived from plants, often accompanied by flavonoids and antioxidants.

• Circadian Rhythm: A 24-hour biological cycle that regulates sleep, hormone release, and metabolism.

• Reactive Oxygen Species (ROS): Molecules that cause oxidative stress and cellular damage.

• Mitochondria: Organelles that generate energy in cells and regulate cell survival.

• CYP1A2: A liver enzyme that breaks down melatonin and other substances.

• MT1/MT2 Receptors: Receptors that mediate melatonin’s effects in the brain and body.

• Chronodisruption: Disturbance of normal circadian rhythms, often from light exposure or irregular schedules.

About the Author

Ed Van Harmelen is the founder of Youth & Earth and a passionate advocate for longevity since 2017. He has been featured in numerous podcasts and wellness publications for his insights on healthy ageing, biohacking, and the science behind supplements. Ed is widely regarded as a pioneer in bringing cutting-edge longevity tools to everyday consumers, making the benefits of advanced anti-ageing science both accessible and actionable.

Medically Reviewed By

Mina Stanisavljevic, M.Sc. in Molecular Biology and Physiology, University of Belgrade. Mina is a Science Advisor at Youth & Earth and OptimallyMe. She specialises in cellular metabolism, healthy ageing, and evidence-based supplement strategies.

Last Updated

July 20, 2025