L-Glutathione Peptide: An Overview of the Literature


The amino acids cysteine, glycine, and glutamic acid comprise the L-glutathione (GSH) tripeptide. When there are too many toxins and free radicals in the environment, they are thought to be important components that protect cells from oxidative stress. Studies suggest that L-Glutathione peptide may not only work as an intracellular free radical scavenger, but it may also stimulate the production of additional antioxidants, including vitamins C and E, coenzyme Q10, and alpha lipoic acid.

L-glutathione is a water-soluble antioxidant hypothesized to have several potential properties, including but not limited to enhancing immunity, speeding wound and burn healing, and decreasing inflammation.

One may find L-Glutathione in nature. Cruciferous vegetables like broccoli, cauliflower, cabbage, meat, fish, and dairy products all contain it. Different amino acids, including L-glutamine, N-acetyl cysteine, N-acetyl methionine, S-adenosylmethionine (SAMe), and L-methionine, seem to contribute to the formation of L-glutathione. These may all become converted from glutathione derivatives into Glutathione.

L-Glutathione Peptide Overview

Research suggests that the amino acids Glutamate and Cysteine undergo a redox reaction, which may produce L-Glutathione. GSH’s cysteine structure contains a sulfur ion, which, via a redox reaction, is thought to neutralize free radicals, peroxides, nitrogen dioxide, and other toxins, thus safeguarding cellular components.

L-glutathione has been suggested to improve cognitive function, reduce stress hormone levels, reduce muscular pain perception, and increase energy levels, all of which are symptoms of chronic fatigue syndrome. While the full scope of this peptide’s potential has yet to be determined, researchers have speculated that it may be able to reduce blood pressure by making the blood less viscous. Researchers further speculate that declining peptide levels may signal illness severity and progression. Garrett Teskey et al., who call L-Glutathione “the master antioxidant,” suggest that:

“Glutathione (GSH) participates in antioxidant defense systems and numerous metabolic processes; consequently, its relevance cannot be emphasized. As predicted, GSH imbalance is seen in a wide variety of clinical disorders, including tuberculosis (TB), HIV, diabetes, cancer, and aging, because GSH deficit puts cells at risk for oxidative damage.” As a result, GSH has been investigated by biological scientists and pharmacologists as a potential target.

L-Glutathione Research Studies

Studies have suggested that this peptide may help proteins fold correctly and create disulfide bonds necessary to attach to their receptors and perform their functions.

Whether or not this peptide may function as a neurotransmitter is continuously debated among scientists. It has been hypothesized that this peptide may stimulate Muller cell ionotropic and purinergic receptors. These cells are believed to exist in the retina and are responsible for maintaining normal retinal cell function. This may prove that Glutathione (GSH) is a neurotransmitter or is critical in preserving normal neurotransmitter function. Retinal Muller cells may also be protected against viral infection and diabetic retinopathy by this peptide’s putative role as a supporting component.

Scientists hypothesize that this peptide may operate as an antioxidant, which might slow down age-related decline, including oxidative damage. Damage to cells and tissues, as well as accelerated endocrine and metabolic aging, have both been linked to oxidative responses.

Investigations purport that Glutathione may have a convoluted relationship with cancer cells. Like other substances, Glutathione has been theorized to slow the development of tumors and cancer-causing chemicals, and this has led to speculation that it might slow the multiplication of cancer cells. To guard against UVB-induced oxidative stress and melanogenesis, Shelan Nagapan et al. suggest that “L-Glutathione may have the potential to be developed as a photoprotection agent.”

A decline in L-Glutathione levels with age has been hypothesized to make the brain more vulnerable to neurodegenerative disorders. Researchers have proposed that the L-Glutathione protein may activate stress response. Stress vulnerability may increase when L-glutathione levels diminish.

Animal studies have hinted at a possible function for the peptide in preserving retinal health and visual acuity. When combined with other antioxidants, L-glutathione peptides have been hypothesized to minimize oxidative stress on the eye and prevent age-related changes, including cataracts and impaired vision.

Research suggests that L-glutathione may help in the formation and upkeep of cartilage. Arthritis and osteoarthritis are conditions thought to be caused by worn or damaged cartilage. L-glutathione may slow the breakdown of cartilage, studies suggest.

In studies, L-glutathione has been speculated to improve cellular levels of the skin, with the added property of perhaps reducing the onset of wrinkles and photoaging.

L-Glutathione Peptide and the Immune System

The possible relationship between L-Glutathione and the immune system has been the subject of much study. Scientists theorize the peptide may eliminate toxins, improving the efficiency of the body’s natural killer (NK) cells. As suggested in clinical studies, HIV-positive research models suggested signs of enhanced immunity after being exposed to the peptide. Researchers hypothesized that this may have been due to the peptide’s potential to increase glutathione levels, which may boost the immune system by encouraging lymphocyte proliferation. Although limited in size, the findings from this study posit the prospective of liposomal GSH as an intervention to enhance tissue GSH levels for use in disease prevention, as suggested by R Sinha et al. As of today, the peptide and associated substances mentioned here are strictly prohibited for human consumption or use by law and are available to researchers strictly for use in contained laboratory settings.


[i] Joseph Pizzorno, Glutathione!, IMCJ Integrative Medicine: A Clinician’s Journal, 2014 Feb, 13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684116/

[ii] Henry Jay Forman et al., Glutathione: Overview of its protective roles, measurement, and biosynthesis, Mol Aspects Med.2009; 30(1-2); 1-12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2696075/

[iii] Teskey G, Abrahem R, Cao R, Gyurjian K, Islamoglu H, Lucero M, Martinez A, Paredes E, Salaiz O, Robinson B, Venketaraman V. Glutathione as a Marker for Human Disease. Adv Clin Chem. 2018;87:141-159 https://pubmed.ncbi.nlm.nih.gov/30342710/

[iv] Bansal A, Simon MC. Glutathione metabolism in cancer progression and treatment resistance. J Cell Biol. 2018 Jul 2;217(7):2291-2298. https://pubmed.ncbi.nlm.nih.gov/29915025/

[v] Nagapan TS, Lim WN, Basri DF, Ghazali AR. Oral supplementation of L-glutathione prevents ultraviolet B-induced melanogenesis and oxidative stress in BALB/c mice. Exp Anim. 2019 Nov 6;68(4):541-548. https://pubmed.ncbi.nlm.nih.gov/31243189/

[vi] Zhu S, Makosa D, Miller B, Griffin TM. Glutathione as a mediator of cartilage oxidative stress resistance and resilience during aging and osteoarthritis. Connect Tissue Res. 2020 Jan;61(1):34-47. https://pubmed.ncbi.nlm.nih.gov/31522568/

[vii] Raghu Sinha et al., Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function, European Journal 2018 Jan. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6389332/

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