Melatonin, self-defence against cancer

Melatonin, self-defence against cancer

Melatonin, a hormone produced by your pineal gland, gut bacteria and mitochondria, is the biggest antioxidant made in our bodies; a powerful anti-inflammatory, it regulates human oestrogen and growth hormone levels and has multiple ways of attacking cancer; experts now believe that everyone with cancer should take at least 20 mg before bed, especially when having chemotherapy. 

Melatonin is a natural hormone, produced by the pineal gland and gut bacteria during darkness, and also by your mitochondria from the action of InfraRed light during the daytime. Several other areas of the body make melatonin.

What is melatonin?


Melatonin, or N-acetyl-5-methoxy-tryptamine, is a hormone produced by the pineal gland in response to circadian rhythms. Its production was thus thought to be affected by time of day, and by the seasons. As night approaches, the body calms and darkness prompts sleep and melatonin is released into the blood (1).


Melatonin is found throughout the plant and animal kingdom, including bacteria and fungi. It has even been found in honey and red wine. 

Little was known about the pineal gland in Western Medicine until 1958 when Aaron B. Lerner reported that it secreted melatonin. However, the Ancient Greeks described this small gland in the middle of the brain as ’The Realm of Thought’; Descartes called it ’The Seat of the Soul’. In Eastern medicine it has long been associated with the ’Third Eye’ and intuition, and it is linked to an important energy chakra. 

The pineal has also been shown to be the link between the nervous system and the 'Limbic System' of the brain. As you will read, the pineal gland could well be the epicentre of the Mind-Body Connection! 


The precursor of melatonin is serotonin, a neurotransmitter found in cells throughout the body; while 95 per cent is produced in the gut helping to improve digestion, its main action is in the brain where it is linked to memory, mood and depression, with further actions in areas such as blood clotting, blood pressure and sexual function (2). Low levels of omega-3, B6, sunlight and vitamin D have been linked to low serotonin, as has a dysfunctional microbiome. Exercise also increases serotonin production, as does a healthy and diverse microbiome.

Serotonin, in turn, is made from the essential amino acid tryptophan via the compound 5-HTP; ‘essential’ means you cannot make it, you must find it in external sources - oily fish, beans, organic eggs, chicken, turkey, greens and dark chocolate. Yes, dark chocolate can help you sleep.

Melatonin, the healing hormone 


There are melatonin receptor sites on cell surfaces all over the body. It is a huge antioxidant, a powerful anti-inflammatory, an analgesic with anti-anxiety benefits and these benefits are why sleep is so healing. Good levels of melatonin production have been linked with anti-aging, reduction of type-2 diabetes, cardiovascular disease, dementia, cancer and more (3). 


Melatonin has been shown to reduce the age-related oxidative stress and inflammatory process in the body. Melatonin has also been shown to affect C-reactive Protein, triglyceride, cholesterol and glucose levels.

Some melatonin is found in the bone marrow, where it has been linked to white-cell formation. Melatonin has also been shown to be involved in the production of lymphocytes and macrophages, and is thus an important factor in the immune system and all illness prevention. 

People with disturbed sleep patterns, and poor melatonin production, develop more illnesses. In cancer, for example, there is research showing long haul air hostesses, night shift workers such as nurses, and even 'party girls', develop more oestrogen-driven cancers. 


Melatonin has been shown in a meta-analysis to reduce human oestrogen, modify oestrogen receptor sites, and generally reduce the ability of cancer cells to grow and spread, having the ability to cause cancer cell death (apoptosis), restrict new blood supplies (anti-angiogenesis), decrease telomerase activity, cause immune modulation, and direct and indirect antioxidant effects (4).

Melatonin and the mitochondria

It then came as a huge discovery to find that mitochondria, the power stations of all your cells, also made melatonin. N-acetyltransferase (SNAT), which helps make melatonin, was found in and around the mitochondria. In ‘Mitochondria: the birth place, battle ground and the site of melatonin metabolism in cells’ (5), the researchers from San Antonio also found melatonin receptors on the mitochondria, not on the cell surface, and the mitochondria were also found to contain a melatonin metabolic enzyme.

Mitochondria have self-sufficiency - they make it and they use it! 

Pineal gland melatonin has now been dubbed ‘Circulatory melatonin’ and this second form is ‘Subcellular melatonin’.


Melatonin and sunlight


Why would all the mitochondria in your body need to make and use melatonin?


Two reasons jump out: 


Firstly, your mitochondria are the power stations in your cells burning the fuel and like any power stations they churn out waste products which, if left around them, would cause them to overheat, and this would produce oxidative stress in the cellular microenvironment, resulting in more toxicity and poorer performance (and your illness). Melatonin is thus made in your mitochondria to protect them from the free-radical and oxidative stress that is produced by them during the day when you are burning more fuel.


Secondly, your mitochondria are the very ‘organs’ that ‘go wrong’ in all chronic illnesses from heart disease, to dementia, diabetes and cancer. All illnesses are metabolic. It is proven for cardiovascular disease, stroke, type-2 diabetes, and dementia. Unless you are one of the seven per cent of people with an inherited genetic mutation, why would you think that cancer is not a metabolic disease too? It all depends upon your cellular microenvironment. Poison it and it will cause you health problems. Keep the environment toxin-free, keep the power stations functioning properly, and illness will be overcome.

Sunlight is electromagnetic radiation given off by the sun. In the middle of the radiation is visible light (sunshine) - the colours of the rainbow. But at the blue end you have ultraviolet light and at the red end you have InfraRed. These are invisible. UVB causes vitamin D production in the cholesterol layers under your skin. It can also damage your skin as can UVA. Most UV light is filtered out by the earth’s atmosphere. At the other end, InfraRed light is very important to us. InfraRed is over 50 per cent of sunlight.

Being outdoors and being in the sun is really good for you. Everybody knows that sunshine warms you but, even through cloud, you receive an unseen benefit. Near InfraRed light actually passes through cloud, penetrates the body and even your bones and passes into your cells and the mitochondria. This light even penetrates your cranium. It promotes health and antioxidant strength. It turns on localised melatonin production in the mitochondria, helps them function, and cleans up the free-radicals and oxidative stress around them. It may well even have the ability to correct malfunctioning mitochondria and cancer cells. Professor Russell Reiter one of the world’s foremost melatonin experts argues this. 

Sunlight doesn’t just give you vitamin D from UVB, it promotes your mitochondrial melatonin via NIR light. Vitamin D and melatonin clearly have links to your good health; for example, vitamin D can stimulate serotonin production. 

Camp fires, candles, firelight and InfraRed saunas can all be beneficial to our health.

The problem is Americans on average spend 93% of their lives indoors. No doubt the British are just as bad. And, of course we had Lockdowns with Covid. But the University of East Anglia has shown that people who live out of doors get less metabolic disease; and that melatonin and vitamin D are ‘good metabolism’ promoters (6). 

Red light by day improves sleep quality at night. One study showed that 14 days of 30 minutes of IR light treatment per day improved the endurance of basketball players (7). 

Other studies (8) have confirmed the role of NIR on the mitochondria. For example, people who get more InfraRed light onto the skin have much higher levels of Cytochrome C oxidase (it is produced by the mitochondria to clean up oxidative stress) and they even have higher levels of oxygenated haemoglobin. Wound healing, brain damage, stroke, bone repair and cancer may all benefit from low intensity InfraRed light because of more melatonin and serotonin production and because of the effects of re-charged water on the cells and power stations (8). 

When sunshine decreases in winter months, glucose and fat metabolism decreases. We become fatter. If we don’t go outdoors into the sunlight, our body’s circadian rhythms just assume we are in winter, and our health suffers.

Melatonin levels even have an effect on gut microbiome composition and this can affect our metabolism (9).

Yes, circadian rhythms and melatonin production are more about the hours of sunlight than the hours of darkness!

In 2015 it was shown that many strains of your gut bacteria live in the dark but have circadian rhythms too. When your pineal gland produces melatonin, they know it is time to ’sleep’ and they produce melatonin. This is why a heavy, late meal disturbs your sleep. It disturbs the sleep of your gut bacteria! If you wake up early each night, it is probably because you have lost important gut bacteria that make melatonin.

What inhibits Melatonin production?

We know that people who get too little sleep have more depression, poorer cognitive function and lowered cancer survival. One third of Americans have too little sleep. 

i) Lack of sleep, good sleep, blue light, EMFs:


Research shows melatonin production is activated, regulated and even damaged by energetic, electrical and magnetic frequencies. These may be your own natural frequency, naturally occuring external frequencies, or external man-made EMFs. EMFs are known to damage melatonin levels.


The production of circulatory melatonin is inhibited by blue light, so put your phone and computer on permanent ‘night shift’ mode (warmer or red light), don’t look at either in the two hours before bedtime, and make the colours of your TV warmer, if watching TV is what you normally do before bed. You must stop all blue light front entering the bedroom and clear out the EMF producers (TV screens, computer systems, wiring).


ii) Waking early:

You wake up when light falls on your iris, and this sends a message to turn off the pineal gland and melatonin production.

iii) Poor sleep preparation:

People who want better sleep should have a routine and accept this natural calming process, going to bed at a regular time and preparing in the same way. Melatonin production is disturbed by eating late, alcohol, smoking, gut issues and low serotonin.

iv) Toxins:

Heavy metals such as lead, aluminium, copper and some forms of iron can block melatonin production and that of its precursors.

v) Age;

Age restricts melatonin production; this is particularly true in the over-60s. Professor Russel Reiter, US expert on melatonin, believes that everybody over 60 should take 5 mg of melatonin simply for its calming antioxidant abilities.

Melatonin and cancer - summary

Melatonin weakens cancer cells – it has clear anti-cancer activity. In fact, it has five separate actions against a wide variety of different cancers – it alters oestrogen receptors, induces apoptosis, restricts metastasis, restricts blood supply formation (angiogenesis), and restores mitochondrial function. 

Melatonin is both a chemosensitiser and radiosensitiser. It weakens cancer cells so that more can be killed by anti-cancer compounds,  And it reduces side-effects from both, restricting chemo- and radiotherapy damage. 

It also seems to turn down oestradiol production, block glucose uptake to cancer cells and regulate cholesterol.

It is made to heal your cells to keep your power stations working properly, and to give you a healthy metabolism. Illness and particularly cancer, finds it hard to thrive in a body with a healthy metabolism. 

Melatonin Supplementation, dosage, warnings

2-3 mg is the legal limit for doctors to prescribe in Europe, Australia and New Zealand. Professor Reiter believes everyone over 60 should take 5 mg before bed; and there is research and there was a recommendation that 20 mg was the right level for fighting cancer from Sloan Kettering and the NCI. So, what is the real ‘correct level’? 

Research has shown that supplements of melatonin rapidly enter the nervous system and cross the blood brain barrier. No negative or side-effects were found.

Some researchers have played with 60-180mg at bedtime; there’s early research with lung cancer, breast cancer and colorectal cancer, suggesting increased survival using 180 mg before bed. Some people use 'Time Release' Melatonin.

Other researchers have used three to six doses of 60 mg by day - there is a review by Shallenberger on the Riordan Clinic website (10). Melatonin by day doesn’t make you sleepy, why would it? It doesn’t prepare you for sleep, the onset of darkness does. Melatonin is just one of 5 hormones that control your circadian rhythm.

At higher doses some 'experts ' claim it ihas much greater cytoxicity. But I watched a CNN review of the 'dangers' of melatonin and they didn't show one piece of evidence to back up their views. Levels of supplementation in mice of up to 300 mg for two years have shown no adverse effects in the mice.  Some cancer centres are now using IV high dose melatonin. No side-effects are reported. In terms of benefit though, I’d just like to see a controlled Clinical Trial before I start suggesting people use high-dose melatonin. 

We do suggest people with cancer take melatonin as a supplement, starting at 5 mg rising to 20 mg. A few people cannot tolerate it (me included!). We especially see people using these levels when having chemotherapy or radiotherapy because it is a proven chemo-and radio-sensitiser.

To help make it by day you need a healthy microbiome plus natural ingredients. Some people take 200 mg of 5 HTP with their breakfast (some take it with breakfast and dinner - 5 HTP crosses readily into the pineal gland). And 5 HTP is easy to get hold of in countries where melatonin is restricted. You should not take 5 HTP if you are on anti-depressants.

And how many people with cancer make sure they get outside every day for a couple of hours? A walk through the woods, a trip to the coast. Even a speed walk round the park. Whatever the weather, sunshine or dark clouds.

Melatonin is the biggest antioxidant we make, it has positive effects all over our bodies and it can protect and correct.


Go to: Melatonin improves chemotherapy effectiveness, increases survival and reduces side-effects




  1. Posadzki PP, Bajpai R, Kyaw BM, Roberts NJ, Brzezinski A, Christopoulos GI, Divakar U, Bajpai S, Soljak M, Dunleavy G, et al. Melatonin and health: An umbrella review of health outcomes and biological mechanisms of action. BMC Med. 2018;16(18) doi: 10.1186/s12916-017-1000-8.

  2. Frazer A, Hensler JG. Serotonin involvement in physiological function and behavior. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999.

  3.  Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action; BMC Med; 2018, Feb 5, (16) 1, Pawel P. Posadzki et al. 

  4. Cardinali et al., 2016. Melatonin-Induced Oncostasis, Mechanisms and Clinical Relevance. J. Integr. Oncol., S1: 006 - 

  5. Tan DX, Reiter RJ. Mitochondria: The birth place, battle ground and the site of melatonin metabolism in cells. Melatonin Res. 2019;2:44–66.

  6. 'The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes'; Environmental Research; 2018 July 6.

  7. Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players; J. Athl Train, 2012, Nov-Dec 47; 

  8. Mitochondrial cytochrome c oxidase is not the primary acceptor for near infrared light—it is mitochondrial bound water: the principles of low-level light therapy; Andrei P Sommer; Ann Transl Med. 2019 Mar; 7(Suppl 1): S13; 

  9. Melatonin prevents obesity through modulation gut microbiota in mice; J Pineal Res; 2017, July; Pengfei Xu et al  - 

10. The Riordan Clinic; Melatonin Overview -


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