What Is It?
Health Benefits
Dosage Information

Guidelines for Use

General Interaction
Possible Side Effects


Evidence Based Rating Scale


What Is It?

Glutathione is an important part of the body's Antioxidant defense system. It is a tripeptide compound composed of three different Amino acids—cysteine, glutamic acid, and glycine—that is primarily produced in the liver.

The antioxidant properties of glutathione neutralize damaging Free radicals and peroxide molecules, and recharge oxidized Vitamin C so that the body may reuse it. Additionally, glutathione is required for a variety of metabolic processes, it bolsters the structure of body proteins, and it assists in the transport of amino acids across cell membranes.

Vitamins B6 and riboflavin are critical for maintaining adequate levels of glutathione within the body. Research suggests that a variety of dietary minerals, including copper and selenium, influence cellular levels of glutathione. In addition, selenium is an essential part of many different forms of glutathione that exist in the body. Other nutrients that help to increase glutathione levels include vitamin A, vitamin E, N-acetylcysteine (NAC), S-adenosylmethionine (SAMe), Alpha Lipoic Acid, and undenatured whey protein. Silymarin, from the herb Blessed Milk Thistle, has also demonstrated an ability to replenish glutathione levels.  (1-5)

Several foods contain naturally occurring glutathione, including: avocado, watermelon, asparagus, grapefruit, potato, acorn squash, strawberries, orange, tomato, cantaloupe, broccoli, okra, peach, zucchini, and spinach. Interestingly, the phytochemical limonene may boost the body's synthesis of a glutathione-containing Enzyme that helps to detoxify certain chemicals and also has antioxidant properties. Limonene is found in citrus fruit peels, cherries, green foods (celery, fennel), soy products, and wheat.

Health Benefits

Glutathione has several health benefits. Optimal amounts of glutathione are necessary for supporting the immune system: in particular, glutathione is required for replication of the lymphocyte immune cells.

Glutathione also helps the liver to detoxify chemicals, such as acetaminophen (Tylenol®), alcohol, and cadmium—a toxic metal that has been associated with a variety of cancers. (6) Scientists speculate that increasing consumption of antioxidants such as glutathione early in life may promote longevity and reduce chronic disease. (7, 8)

Research is currently exploring the potential benefits of glutathione for several conditions including cancer, cataracts, heart disease, memory loss, osteoarthritis, Parkinson's disease, cornea disorders, kidney dysfunction, eczema, liver disorders, poisoning by heavy metals, and immunodepression that occurs in diseases such as AIDS.

Specifically, glutathione may help to:

Reduce the risk of some cancers. Some evidence indicates the antioxidant properties of glutathione may be effective in fighting cancer-causing free radicals, thus helping to reduce the risk of certain types of cancer. (9, 10)

Interestingly, in one study in which a 3-gram dosage of oral glutathione was given, oral supplementation did not increase plasma glutathione levels. (11) Rather, eating foods, especially raw foods that contain glutathione seems to show the most benefit in cancer risk reduction. For example, in a population-based observational study with 1,830 participants, a reduced risk of new oral cancers was associated with higher consumption of glutathione derived from fruits and vegetables that are usually consumed raw compared to glutathione derived from other vegetables and from meat. (12)

Reduce the side-effects of cancer therapies. Glutathione may be useful in conjunction with conventional therapies for treating cancer. Several studies suggest that increasing glutathione levels helps to protect healthy cells while increasing cancer cell destruction during conventional cancer treatments such as chemotherapy. One set of studies observed the effects of a specific whey protein concentrate (Immunocal) that provides cysteine as a precursor to glutathione. Glutathione levels in prostate cancer cells were normalized in the studies. It is unclear whether the same benefit would be seen with other forms of whey supplementation, and small studies in cancer patients have not had a clear impact on cancer survival. (13-15)

Other studies in humans have focused on toxicity during conventional cancer treatment. Several studies have found that administering glutathione by intravenous injection along with chemotherapy seems to help decrease toxicity from chemotherapy, especially when using platinum containing chemotherapeutic agents, thus allowing for more chemotherapy doses. Quality of life was also improved during treatment of cancers of the breast, bone marrow, colon, larynx, lung, ovary, and stomach. (16-27)

Relieve symptoms of Parkinson's disease. Studies have shown that glutathione deficiency is present in Parkinson's disease, a progressive nervous system disorder that causes physical symptoms such as tremors, rigidity, loss of coordination and a slow, shuffling gait. (28-34) Adequate glutathione levels may help to protect the brain from free-radical damage and may also increase the body's sensitivity to dopamine, which relays messages between nerve and muscle cells. A 1999 study found that elevating levels of glutathione through injection of N-acetylcysteine (NAC) protected against a particular form of free radical-induced oxidative stress in rat brains. (35) Studies evaluating glutathione supplementation for Parkinson's disease are limited. A 2006 review of antioxidant use in Parkinson’s disease found only one study involving glutathione. With fewer than 30 subjects, it did show a small but statistically significant improvement in symptoms of Parkinson's disease. (36) However, a 2009 study had conflicting results. In the study, 20 patients with Parkinson's disease received either 1,400 mg of intravenous glutathione or placebo three times a week for twelve weeks. Over the first four weeks, Unified Parkinson's Disease Rating Scale (UPDRS) scores and motor scores improved by a mean of 2.8 units more in the treatment group. However, scores worsened in the treatment group with continued glutathione supplementation in the eight subsequent weeks. (37) Larger studies are needed to establish appropriate doses and timing of glutathione therapy.

Prevent heart disease. The antioxidant properties of glutathione may be beneficial in preventing heart disease, which is characterized by a narrowing of the arteries that supply the heart with blood, oxygen and nutrients. Scientists believe that free radicals are responsible for oxidation of the LDL ("bad") cholesterol that can lead to the clogged arteries in heart disease. By scavenging the free radicals, glutathione may help to prevent the risk factors that lead to heart disease. A preliminary study in 2004 compared plasma glutathione levels in 134 patients with heart disease to those of healthy control subjects. Mean glutathione levels were lower in all heart disease cases than in control subjects, suggesting that low levels of glutathione present a risk factor for heart disease. (38) A similar study in 2009 measured plasma glutathione levels in 76 patients undergoing surgery for various heart conditions (coronary artery disease, aortic stenosis or terminal cardiomyopathy) and in 15 healthy volunteers of comparable age. Compared to healthy controls, blood glutathione was decreased by 21% in New York Heart Association (NYHA) class I patients with heart disease, and by 40% in patients with NYHA class II-IV symptoms of heart disease suggesting an association between glutathione deficiency and abnormal heart function. (39) However, studies are needed to determine whether supplementation is helpful for preventing heart disease.

Improve memory loss. Studies have shown oxidative stress is a key factor in Alzheimer's disease, a degenerative disorder of the brain that severely impairs memory and mental function. Protecting the brain from free radical damage helps to prevent memory loss. The study described above that showed beneficial effects of injecting glutathione into the brains of rats with Parkinson's disease also noted its benefits against oxidative stress in Alzheimer's disease. The study showed that neurodegenerative diseases such as Alzheimer's disease may benefit from the protective effects of increasing levels of glutathione. (35) Human studies are needed.

Reduce inflammation in osteoarthritis. The anti-inflammatory properties of glutathione may be beneficial in treating the joint pain and swelling of osteoarthritis (OA). A 2003 study of joint cartilage from young and old adult human tissue donors found that the increased oxidative stress that accompanies aging impairs the glutathione antioxidant system and makes the cells in joint cartilage more susceptible to inflammation and OA. (40) A 2008 study of joint fluid samples from 28 patients with severe OA showed a significant decrease in glutathione levels compared to fluid from a control group of patients with pain or sub-acute injury in their knee joints but who had macroscopically intact cartilage. (41)

Prevent vision problems. Glutathione plays an important role in protecting the eyes from harmful toxins and maintaining a healthy lens. Studies have shown that glutathione deficiency is associated with age-related macular degeneration (AMD) and cataracts. (42, 43) A 2000 review of studies evaluating diet, environmental and behavioral risk factors for AMD found that therapeutic or nutritional intervention may enhance the glutathione capacity of the cell layer that nourishes retinal visual cells. (44) Glutathione has been shown to be critical in preventing the development of cataracts, a disorder in which the lens of the eye loses its normal transparency and begins to impair vision. Cataracts are generally characterized by extensive oxidation of lens proteins, and some research has shown glutathione is the key defense against oxidation in the lens. (45, 46) Increasing glutathione levels in glutathione-deficient rats was shown to prevent the formation of cataracts. (47) More research in humans is needed.

Improve survival in AIDS. Patients with Acquired Immunodeficiency Syndrome (AIDS) seem to have low levels of reduced glutathione, which may result in increased HIV expression and impaired T cell function. (48) Boosting glutathione, then, may be important in improving immune function in these patients. The glutathione precursor N-acetylcysteine (NAC) boosts glutathione production and supports the proper functioning of immune-system components such as T cells, B cells, and phagocytes, all of which are important for maintaining the body’s defenses and potentially protecting against AIDS-related illnesses. (49-51) One study indicates that a glutathione deficiency in CD4 T cells is associated with decreased survival time: the probability that HIV-infected subjects will die within two to three years is dramatically higher with glutathione-deficient CD4 T cells. Combined with the evidence that NAC is efficacious in replenishing glutathione levels, the researchers suggested glutathione is a key factor for survival in HIV disease and that the prolonged or extensive use of conventional medications known to deplete levels of glutathione  (such as acetaminophen) should be avoided in HIV patients. (49)

Treat respiratory conditions. The free radical scavenging properties of glutathione are important in the respiratory tract to combat oxidative stress during conditions such as strenuous exercise, smoking. and Farmer's lung.  Glutathione deficiency has also been associated with chronic obstructive pulmonary disease. (52) Treatment studies have shown that inhalation is the only effective method of increasing glutathione in the cells lining the lower respiratory tract. (53)


  • capsule
  • liquid
  • tablet
  • aerosol for inhalation
  • intramuscular
  • intravenous (IV) 

Dosage Information

A Recommended Dietary Allowance (RDA) has not been established for glutathione, and no studies have demonstrated significant absorption from oral supplements. Ingesting raw fruits and vegetables and supplements of glutathione precursors such as vitamin A, vitamin E, N-acetylcysteine (NAC), S-adenosylmethionine (SAMe), and Alpha-lipoic acid have the greatest possibility of raising glutathione levels for general health. For dosage recommendations, please see the WholeHealthMD articles on these supplements.

For integrative treatment of disease conditions, ask your physician about adding glutathione to your regimen via inhalation, intramuscular, or intravenous routes.

Guidelines for Use

Eating ample amounts of raw fruits and vegetables and glutathione precursors is associated with higher glutathione levels. However, oral supplementation of pure glutathione does not seem to improve levels; therefore, it is not recommended.

Glutathione is most effective when administered intravenously, via intramuscular injections, or via aerosol or nebulizer for respiratory conditions. Consult a doctor for recommendations and prescriptions for glutathione.

General Interaction

There are no known interactions of glutathione with food.

Possible Side Effects

There are no known side effects of glutathione.


If there is a concern about glutathione levels, avoid drugs that contain acetaminophen (Tylenol®) because it depletes levels of glutathione.


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Date Published: 04/18/2005
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