Clayton's Health Facts: L-Glutathione.

Clayton South, SPN (ISSA), is a recognized expert in the bodybuilding / fitness industry with over 150 bodybuilding, fitness and nutrition publications to his credit.

What is it and where does it come from?

Glutathione (C10H17N3O6S) is a tri-peptide - a protein - comprised from one amino acid of glutamic acid, cysteine and glycine. Glutathione is found and manufactured in every cell in the body but is found in highest concentrations in the heart, muscle tissue and the liver. Glutathione is critical for healthy immune system function.

Dietary sources of glutathione and glutathione precursors include meats, fish. fruits, vegetables, avocado, walnuts and asparagus. Glutathione precursors are also found in whey protein concentrate.

What does it do and what scientific studies give evidence to support this?

Glutathione is critical for the healthy maintenance of the immune system.

Glutathione helps the body fight almost any disease, because it is a powerful antioxidant that helps maintain cellular health and helps prevent oxidative stress. Glutathione has been heavily researched, and the findings on this substance have been nothing short of amazing.

Aside from being a powerful antioxidant booster1 and system detoxifier, glutathione helps produce, protect and repair deoxyribonucleic acid - DNA. In this protective role, glutathione boosts the immune system, thereby helping to power immune response and preventing the growth of cancerous cells.2

Glutathione's action against cancer is so profound that glutathione supplementation may enhance the effects of chemotherapy cancer treatment and reduce the associated side-effects. In fact, the glutathione in whey protein is believed to interfere with the normal feedback mechanism and regulation of glutathione in cancer cells, thus depriving the damaged cells of glutathione, making them more vulnerable to chemotherapy treatments. This partially explains the anti-cancer effects seen with whey protein use.

Glutathione levels help protect the body from oxidative stress - and oxidative stress is associated with ageing. Thus, glutathione levels are correlated with aging and physical function. One way to drastically increase glutathione levels, aside from consuming glutathione precursors, is through the ingestion of ascorbic acid - vitamin C3 - and l-glutamine and ALA (Alpha Lipolic Acid).

Boosting glutathione levels has been shown to boost sperm count in infertile men4 and non-weight training subjects saw increases in muscle mass by supplementing with glutathione, even without weight training.5

Glutathione is essential for immune system function and muscle growth, and any athlete who is glutathione deficient will suffer from decreased performance6 and a lack of muscle growth.7

Who needs it and what are some symptoms of deficiency?

Everyone can benefit from glutathione supplementation

Declines in glutathione levels are associated with ageing, and studies have shown that adults who took glutathione had better health than those who did not.8 So, glutathione supplementation is especially important for this population.

Hard training is known to deplete glutathione levels. Thus, the hard-training athlete can benefit especially from glutathione supplementation and the enhanced recovery and muscle building results seen from its use.

Persons with low glutathione levels can include: smokers, those with HIV / AIDS, diabetics, men with low sperm counts / impotence, and Alzheimer's and cancer patients.

Deficiencies of glutathione do not produce diseases, but low glutathione levels can accelerate ageing, can lead to functional decline and weaken the immune system.

How much should be taken? Are there any side effects?

Strictly adhere to label directions. No side effects of glutathione use are known.

Research has conflicted as to whether glutathione is effectively absorbed in human subjects.9,10,11 but one study suggests that glutathione is best taken by letting a tablet dissolve in the mouth that is placed between the teeth and the inner cheek.12

Glutathione pre-cursor supplementation should be avoided by persons with milk protein allergies, as well as those who have received organ transplants.


  1. Bounous G, Molson J. Competition for glutathione precursors between the immune system and the skeletal muscle: pathogenesis of chronic fatigue syndrome. Med Hypothesis 53;(4): 347-349
  2. Sen CK. Nutritional biochemistry of cellular glutathione. Nutr Biochem 1997;8:660-72.
  3. Johnston CS, Meyer CG, Srilakshmi JC. Vitamin C elevates red blood cell glutathione in healthy adults. Am J Clin Nutr 1993;58:103-5.
  4. Lenzi A, Culasso F, Gandini L, et al. Placebo-controlled, double-blind, cross-over trial of glutathione therapy in male infertility. Hum Reprod 1993;8:1657-62.
  5. Lands LC, Grey VL and Smountas AA. Effect of a cysteine donor on muscular performance.J Appl Physiol. 87 (4):1381-1385 1999.
  6. Powers SK, JI LL, Leeuwenburgh C. Exercise training-induced alterations in skeletal muscle antioxidant capacity:a brief review. Med. Sci. Sports Exerc. Vol31#7:987-997 1999.
  7. Sen CK. Glutathione homeostasis in response to exercise training and nutritional supplements. Molecular & Cellular Biochemistry. 196:31-42 1999
  8. Julius M, Lang C, Gleiberman L, et al. Glutathione and morbidity in a community-based sample of elderly. J Clin Epidemiol 1994;47:1021-6.
  9. Hagen TM, Wierzbicka GT, Sillau AH, et al. Fate of dietary glutathione: disposition in the gastrointestinal tract. Am J Physiol 1990;259(4Pt1):G530-5.
  10. Favilli F, Marraccini P, Iantomasis T, Vincenzini MT. Effect of orally administered glutathione on glutathione levels in some organs of rats: role of specific transporters. Br J Nutr 1997;78:293-300.
  11. Witschi A, Reddy S, Stofer B, Lauterburg BH. The systemic availability of oral glutathione. Eur J Clin Pharmacol 1992;43:667-9.
  12. Hunjan MK, Evered DF. Absorption of glutathione from the gastro-intestinal tract. Biochim Biophys Acta 1985;815:184-8.