RESEARCH STARTER

Glutathione as a therapeutic supplement

Glutathione is a naturally occurring antioxidant in the human body, primarily composed of the amino acids cysteine, glutamic acid, and glycine. As a crucial component of the antioxidant defense system, it helps neutralize harmful free radicals and maintains essential biological molecules in a reduced state. Glutathione is particularly active in the liver, where it also plays a role in detoxifying various harmful substances. While oral glutathione supplements are commonly marketed for their health benefits, they are largely ineffective as they are not absorbed by the body; however, certain nutrients like vitamin C and cysteine may help elevate glutathione levels.

Therapeutically, glutathione is used in medical settings, notably via injection or inhalation, for conditions such as acetaminophen overdose and cystic fibrosis. Evidence suggests that it may also assist in reducing side effects of chemotherapy, enhance skin health, and serve as a potential immune system booster. Despite its benefits, there remains uncertainty about the efficacy of raising glutathione levels through supplementation. Generally, glutathione is considered safe since oral forms do not enter systemic circulation effectively. For those interested in its therapeutic potential, exploring alternative methods to increase glutathione levels may be worthwhile.

Full Article

DEFINITION: Natural substance of the human body used as a supplement to treat specific health conditions.

  • PRINCIPAL PROPOSED USES: Acetaminophen overdose, cystic fibrosis, and prevent kidney damage
  • OTHER PROPOSED USE: Antioxidant, boost immunity, detoxify, skin health

Overview

Dangerous, naturally occurring substances in the body called free radicals pose a risk to many tissues. The body deploys an antioxidant defense system to hold free radicals in check. Glutathione, a protein made from the amino acids cysteine, glutamic acid, and glycine, is one of the most important elements of this system.

Glutathione does much of its work in the liver, although it is also found elsewhere in the body. Besides fighting free radicals, it helps keep various essential biological molecules in a chemical state called reduced (as opposed to oxidized). In addition, glutathione can act on toxins such as pesticides, lead, and dry cleaning solvents, transforming them so the body can excrete them more easily.

Nutrients such as vitamin C and vitamin E also help neutralize free radicals. In the 1990s, such antioxidant supplements were widely promoted for preventing a variety of diseases, including cancer and heart disease. During this period, oral glutathione became popular as an additional antioxidant supplement. Glutathione is not absorbed by mouth, so such supplements are useless. It may be possible, however, to raise glutathione levels in the body by taking other supplements, such as vitamin C, cysteine, lipoic acid, and N-acetylcysteine. Whether doing so would offer any health benefits remains unclear.

Requirements and Sources

There is no dietary requirement for glutathione. The body makes it from scratch, utilizing vitamins and common amino acids found in food. Cigarette smoking reduces glutathione levels in the body. Various diseases, including cancer, cataracts, diabetes, and human immunodeficiency virus (HIV) infection, are associated with reduced levels of glutathione.

Therapeutic Dosages

A typical recommended dose of oral glutathione is 50 milligrams twice daily. However, when glutathione is taken by mouth, it is destroyed. Therefore, no matter the dose, it will not make any difference. Some glutathione may be absorbed if it is held in the mouth and allowed to dissolve, but this has not been well studied.

A more promising method for raising glutathione levels in the body involves taking supplemental cysteine or antioxidant supplements. Evidence suggests that cysteine (often supplied in the form of whey protein, which is high in cysteine) can raise glutathione levels in people with cancer, hepatitis, or HIV.

In addition, because vitamin C has overlapping functions with glutathione, vitamin C supplements may spare some of the body’s glutathione from being used up, thereby increasing its levels in the body. The antioxidant supplement lipoic acid appears to raise glutathione levels as well. Other supplements that might raise glutathione levels include N-acetylcysteine, glutamine, methionine, and S-adenosyl methionine (SAMe).

Therapeutic Uses

Various websites promote glutathione for various health problems, from preventing aging to enhancing sports performance. Glutathione has been suggested as a general immune system booster and body detoxifier. It may also impact skin health, improving skin tone and the appearance of fine lines and wrinkles. However, oral glutathione supplements are useless for any condition since they are not absorbed. 

There is a bit of evidence that injected glutathione might offer a few health benefits. These include preventing blood clots during surgery, reducing the side effects and increasing the effectiveness of cancer chemotherapy drugs such as cisplatin, treating male infertility, and alleviating symptoms of early Parkinson’s disease. Intravenous glutathione is often used to treat an acetaminophen overdose to protect the liver from damage. It may also help protect the kidneys during imaging scans. Inhaled glutathione is given to patients with cystic fibrosis to increase lung function and prevent respiratory infection. Although oral glutathione is not likely to provide the same benefits, it is at least theoretically possible that taking the nutrients described in the previous section (and thereby raising glutathione levels indirectly) could offer similar benefits. 

Safety Issues

Oral glutathione should be entirely safe, since it is not absorbed.


Bibliography

Bharath, S., et al. "Glutathione, Iron, and Parkinson’s Disease." Biochemical Pharmacology, vol. 64, 2002, pp. 1037-48.

Bounous, G. "Whey Protein Concentrate (WPC) and Glutathione Modulation in Cancer Treatment." Anticancer Research, vol. 20, 2000, pp. 4785-92.

De Rosa, S. C., et al. "N-Acetylcysteine Replenishes Glutathione in HIV Infection." European Journal of Clinical Investigation, vol. 30, 2000, pp. 915-29.

Droge, W., and R. Breitkreutz. "Glutathione and Immune Function." Proceedings of the Nutrition Society, vol. 59, 2000, pp. 595-600.

"Glutathione: Health Benefits, Safety Information, Dosage, and More." WebMD, 30 Sept. 2024, www.webmd.com/diet/health-benefits-glutathione. Accessed 8 Dec. 2025.

Hultberg, B., et al. "Lipoic Acid Increases Glutathione Production and Enhances the Effect of Mercury in Human Cell Lines." Toxicology, vol. 175, 2002, pp. 103-10.

Lefton, Jennifer. "Glutathione: Uses, Side Effects, & More." Verywell Health, 4 Dec. 2025, www.verywellhealth.com/benefits-of-glutathione-89457. Accessed 8 Dec. 2025.

Lenzi, A., et al. "Lipoperoxidation Damage of Spermatozoa Polyunsaturated Fatty Acids (PUFA): Scavenger Mechanisms and Possible Scavenger Therapies." Frontiers in Bioscience, vol. 5, Jan. 2000, pp. E1-E15.

Packer, L., et al. "Molecular Aspects of Lipoic Acid in the Prevention of Diabetes Complications." Nutrition, vol. 17, 2001, pp. 888-95.

Sharma, Dave K., and Peeyush Sharma. "Augmented Glutathione Absorption from Oral Mucosa and Its Effect on Skin Pigmentation: A Clinical Review." Clinical, Cosmetic and Investigational Dermatology, vol. 15, 2022, p. 1853, doi.org/10.2147/CCID.S378470. Accessed 8 Dec. 2025.

Full Article

DEFINITION: Natural substance of the human body used as a supplement to treat specific health conditions.

  • PRINCIPAL PROPOSED USES: Acetaminophen overdose, cystic fibrosis, and prevent kidney damage
  • OTHER PROPOSED USE: Antioxidant, boost immunity, detoxify, skin health

Overview

Dangerous, naturally occurring substances in the body called free radicals pose a risk to many tissues. The body deploys an antioxidant defense system to hold free radicals in check. Glutathione, a protein made from the amino acids cysteine, glutamic acid, and glycine, is one of the most important elements of this system.

Glutathione does much of its work in the liver, although it is also found elsewhere in the body. Besides fighting free radicals, it helps keep various essential biological molecules in a chemical state called reduced (as opposed to oxidized). In addition, glutathione can act on toxins such as pesticides, lead, and dry cleaning solvents, transforming them so the body can excrete them more easily.

Nutrients such as vitamin C and vitamin E also help neutralize free radicals. In the 1990s, such antioxidant supplements were widely promoted for preventing a variety of diseases, including cancer and heart disease. During this period, oral glutathione became popular as an additional antioxidant supplement. Glutathione is not absorbed by mouth, so such supplements are useless. It may be possible, however, to raise glutathione levels in the body by taking other supplements, such as vitamin C, cysteine, lipoic acid, and N-acetylcysteine. Whether doing so would offer any health benefits remains unclear.

Requirements and Sources

There is no dietary requirement for glutathione. The body makes it from scratch, utilizing vitamins and common amino acids found in food. Cigarette smoking reduces glutathione levels in the body. Various diseases, including cancer, cataracts, diabetes, and human immunodeficiency virus (HIV) infection, are associated with reduced levels of glutathione.

Therapeutic Dosages

A typical recommended dose of oral glutathione is 50 milligrams twice daily. However, when glutathione is taken by mouth, it is destroyed. Therefore, no matter the dose, it will not make any difference. Some glutathione may be absorbed if it is held in the mouth and allowed to dissolve, but this has not been well studied.

A more promising method for raising glutathione levels in the body involves taking supplemental cysteine or antioxidant supplements. Evidence suggests that cysteine (often supplied in the form of whey protein, which is high in cysteine) can raise glutathione levels in people with cancer, hepatitis, or HIV.

In addition, because vitamin C has overlapping functions with glutathione, vitamin C supplements may spare some of the body’s glutathione from being used up, thereby increasing its levels in the body. The antioxidant supplement lipoic acid appears to raise glutathione levels as well. Other supplements that might raise glutathione levels include N-acetylcysteine, glutamine, methionine, and S-adenosyl methionine (SAMe).

Therapeutic Uses

Various websites promote glutathione for various health problems, from preventing aging to enhancing sports performance. Glutathione has been suggested as a general immune system booster and body detoxifier. It may also impact skin health, improving skin tone and the appearance of fine lines and wrinkles. However, oral glutathione supplements are useless for any condition since they are not absorbed. 

There is a bit of evidence that injected glutathione might offer a few health benefits. These include preventing blood clots during surgery, reducing the side effects and increasing the effectiveness of cancer chemotherapy drugs such as cisplatin, treating male infertility, and alleviating symptoms of early Parkinson’s disease. Intravenous glutathione is often used to treat an acetaminophen overdose to protect the liver from damage. It may also help protect the kidneys during imaging scans. Inhaled glutathione is given to patients with cystic fibrosis to increase lung function and prevent respiratory infection. Although oral glutathione is not likely to provide the same benefits, it is at least theoretically possible that taking the nutrients described in the previous section (and thereby raising glutathione levels indirectly) could offer similar benefits. 

Safety Issues

Oral glutathione should be entirely safe, since it is not absorbed.


Bibliography

Bharath, S., et al. "Glutathione, Iron, and Parkinson’s Disease." Biochemical Pharmacology, vol. 64, 2002, pp. 1037-48.

Bounous, G. "Whey Protein Concentrate (WPC) and Glutathione Modulation in Cancer Treatment." Anticancer Research, vol. 20, 2000, pp. 4785-92.

De Rosa, S. C., et al. "N-Acetylcysteine Replenishes Glutathione in HIV Infection." European Journal of Clinical Investigation, vol. 30, 2000, pp. 915-29.

Droge, W., and R. Breitkreutz. "Glutathione and Immune Function." Proceedings of the Nutrition Society, vol. 59, 2000, pp. 595-600.

"Glutathione: Health Benefits, Safety Information, Dosage, and More." WebMD, 30 Sept. 2024, www.webmd.com/diet/health-benefits-glutathione. Accessed 8 Dec. 2025.

Hultberg, B., et al. "Lipoic Acid Increases Glutathione Production and Enhances the Effect of Mercury in Human Cell Lines." Toxicology, vol. 175, 2002, pp. 103-10.

Lefton, Jennifer. "Glutathione: Uses, Side Effects, & More." Verywell Health, 4 Dec. 2025, www.verywellhealth.com/benefits-of-glutathione-89457. Accessed 8 Dec. 2025.

Lenzi, A., et al. "Lipoperoxidation Damage of Spermatozoa Polyunsaturated Fatty Acids (PUFA): Scavenger Mechanisms and Possible Scavenger Therapies." Frontiers in Bioscience, vol. 5, Jan. 2000, pp. E1-E15.

Packer, L., et al. "Molecular Aspects of Lipoic Acid in the Prevention of Diabetes Complications." Nutrition, vol. 17, 2001, pp. 888-95.

Sharma, Dave K., and Peeyush Sharma. "Augmented Glutathione Absorption from Oral Mucosa and Its Effect on Skin Pigmentation: A Clinical Review." Clinical, Cosmetic and Investigational Dermatology, vol. 15, 2022, p. 1853, doi.org/10.2147/CCID.S378470. Accessed 8 Dec. 2025.

More Like ThisRelated Articles

Related Articles (5)

Related Articles (5)