Glutathione - the most powerful antioxidant in your body

Glutathione - the most powerful antioxidant in your body

Glutathione or GSH is an antioxidant, naturally produced in your body from three amino acids, glycine, cysteine and glutamine (glutamic acid). It is produced by your liver and by your nerve cells. It is crucial in managing oxidative stress and a deficiency is linked to chronic illness and premature aging.

Although Glutathione is found everywhere in our bodies, it is the liver that has the highest concentrations of this very special substance. Glutathione is also found in plants, fungi, animals and some single cell organisms.

The Master Detoxifier

It is an antioxidant - in particular it is thought to neutralise free radicals and oxidative stress in the microenvironment of your cells. For this reason it has been called The Master Detoxifier.

Oxidative stress is one of the biggest health problems we face. It leads to a whole range of chronic illnesses and premature aging. Glutathione is the most natural treatment for oxidative stress and better than almost any supplement. Oxidative stress - free radicals and oxidants - appears in the microenvironment of your cells leading to cell membrane damage and then damage inside the cell.

Glutathione appears in two forms in the body: 

     i) Lowered glutathione (GSH) neutralises oxidative stress, turning free-radicals into non-toxic products in all chronic illnesses. It’s a crucial part of the immune system. Thus GSH is an essential but missing or lowered factor in the causation of human diseases from cancer to cardiovascular disease. 


     ii) Oxidised glutathione or GSSG, accumulates in cells that had high oxidative stress, after the GSH is consumed. 


Glutathione is also known to repair your telomeres - the 'caps' at each end of your DNA holding the double helix together. Damaged telomeres cause DNA unravelling and are associated with cancer, other chronic illnesses and early aging.


Glutathione is also the brain’s primary antioxidant. In the healthy brain, 2016 research shows its continued presence in a stable amount from cradle to grave (1). But reduced levels have been found in depression, schizophrenia, Alzheimer’s addiction, autism and bipolar disorder.


If you lived in a cocoon and had a great diet, your glutathione levels do not appear to decline in your organs but only in your blood as you age (2). The tipping point for blood levels starts around age 40-45.

The most crucial point is that you must not have a shortage of glutathione. But equally, an excess can also be damaging. Some free-radicals and oxidants are needed by the body. For example, you need some as a defence against pathogens (see later).

What damages Glutathione levels?

GSH levels in the body are reduced by stress, alcohol, poor diet (sugar, grains, processed and refined foods), paracetamol and environmental toxins. If this occurs, the free-radicals remain in excess and can carry out their mischief unchecked.

Chemotherapy and radiotherapy also worsen GSH levels, but glutathione has been shown to reverse healthy cell damage and nerve damage after such treatments.

Glutathione and diet

People suffering from cancer or other chronic illnesses can increase their body’s natural glutathione levels by restricting environmental toxins such as herbicides and pesticides, and avoiding poor quality (mass-market) foods including those grown on poor quality soils.

Glutathione includes sulphur molecules and so foods high in sulphur increase its presence:

  • Garlic, onions, leeks

  • Raw vegetables including cruciferous vegetables, broccoli, cabbage, Brussel’s sprouts, bok choy

  • Free range egg whites 

  • Pulses (legumes) such as lentils, chickpeas

  • Lean protein - chicken, turkey, fish

  • Mustard, ground ginger

Other foods known to boost the production of glutathione are

  • Whey protein

  • Flaxseed

  • Milk Thistle

  • Sea weeds


What else increases glutathione levels?


Good levels of sleep improve glutathione levels while poor sleep causes a decline in levels. Both aerobic exercise and weight training increase glutathione levels.


Supplementation can be good; can be bad


Glutathione is a natural compound that is largely made and regulated from a healthy diet. Providing you have a good, healthy diet with strong levels of the foods such as greens and flaxseed as suggested above, your body will make what it needs. You can encourage it to make more as you age, but 'regulation' is crucial (this is rather like taking beta-carotene instead of vitamin A supplements and allowing the body to make the vitamin A it needs, so you don't poison your liver.


If you are thinking of taking supplements of glutathione, these are of limited value as they are degraded by normal atmospheric conditions, temperature and your digestive processes. Some people take liposomal forms to try to move the glutathione faster into the blood stream but, as we said above, this could be dangerous because the body NEEDS to regulate glutathione. You don’t need more if you already have a healthy brain, but some of the new unregulated supplementation will almost certainly reach the brain and could cause damage.

Perhaps it would be better to use the precursors glycine and cysteine, but not glutamine, an amino acid, which can be converted into glutamate, not necessarily a good thing if you have cancer as it can act as a reserve fuel! By adding glycine and cysteine, you are providing more raw materials and encouraging increases, but still allowing the body to regulate production and volume.

In elderly people there is research (3) showing that dietary supplementation with cysteine and glycine can increase glutathione in the blood by 94.6%. This has led some people to recommend taking N-acetyl cysteine (NAC) but again, this is broken down by normal digestive processes. And it can thin the blood. 

There is also research in elderly mice using a supplement of glycine, which shows a small but significant increase in lifespan (4).

Green juices - excellent for 'regulated' glutathione production

Inevitably, diet is crucial. High levels of vegetables, pulses and garlic are good. Says Chris Woollams, one of the CANCERactive founders and a former Oxford University biochemist, “ Encouraging glutathione increases but allowing regulation to take place, is crucial and one of the reasons I suggest people with cancer make daily green vegetable juices or green vegetable smoothies with no fruit in them. So many people say it made a huge difference to how they feel and look and they usually get really good results with their cancer programme. Glutathione is naturally produced by the body; it’s part of our natural defence system, maintaining a healthy redox balance. But by 40 we are making 30% less and by 65 we are making 50% less, which is why cancer risk increases as we age. There may well be an argument for also adding the amino acids glycine and cysteine to your green juices after age 65."

Glutathione and cancer roduction

"But just as GSH increases detoxification of compounds like toxins and carcinogens that shouldn't be in a healthy cellular microclimate and lowered GSH levels can promote cancer, by-passing the natural regulation system and having excess GSH levels can actually be dangerous. It's a double edged sword.

According to research (5), elevated GSH levels (for example, through supplementation using glutathione itself) can promote cancer growth and metastasis. Excess GSH may even provide cancers with resistance to drugs.

So, by all means stimulate natural glutathione production to avoid deficiency, but ensure natural healthy regulation."

Go to:  Glutamine, Glutamate, diet and cancer





  1. Free Radic Biol Research; 2016 Apr; 93:110-117; Junchao Tong et al - 

  2. Free Radic Biol Med. 2002 Nov 1; 33 (9) Dean Jones et al: Redox analysis of human Plasma - 

  3. Am J Clin Nutr 2011 Sep; 94(3) 847-853 Rajagopal V Sekhar et al: - 

  4. Aging Cell 2018 Jun; 18 (3); Glycine supplementation extends lifespan of male and female mice - 

  5. Glutathione metabolism in cancer -


  Approved by the Medical Board. Click Here 


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