Glutathione is a master antioxidant, meaning it can help neutralize a wide range of free radicals in the body. This article explains the roles glutathione plays in the body, focusing on why it matters for healthy aging. We review how glutathione supports the eyes’ natural defenses against oxidative stress. And, we discuss research linking lower glutathione levels with common vision concerns such as cataracts, glaucoma, and macular degeneration, along with a brief look at emerging research on glutathione’s role in cellular protein handling. It also covers practical ways to support glutathione through diet and supplementation.
What is Glutathione?
Glutathione is a potent antioxidant that plays several essential roles in the body, from neutralizing free radicals to supporting cellular repair and recovery from damage. Beyond general antioxidant defense, glutathione helps maintain iron levels and supports healthy mitochondrial function. Glutathione and the endoplasmic reticulum also work in coordination with mitochondria to help maintain cellular stability.
Glutathione is especially important in defending against oxidative stress, a major driver of many ocular conditions. The eyes are continually exposed to light in order to gather information from the outside environment. However, this exposure to light can generate reactive oxygen species through ionizing and non-ionizing radiation.1 Even in darkness, the retina consumes large amounts of oxygen-often more than it does in light-making it particularly vulnerable to oxidative damage.
To counter this risk, the eye relies on multiple protective systems, including high levels of ascorbic acid (vitamin C) and glutathione.2 Additional defenses include enzymatic antioxidants such as superoxide dismutase, glutathione peroxidase, and catalase, along with non-enzymatic antioxidants like cysteines, tocopherols, and retinols. Together, these systems help protect retinal cells and support lens clarity, helping maintain healthy vision over time.3
Groundbreaking Research on Glutathione
A 2026 Nature Cell Biology study describes a new way cells protect the endoplasmic reticulum-the cell’s protein-folding “factory”-by controlling glutathione balance.4 The researchers identify SLC33A1 as a transporter that exports oxidized glutathione, which helps maintain endoplasmic reticulum redox homeostasis (a stable chemical environment needed for accurate protein folding).
The main takeaway is that glutathione isn’t just a general antioxidant. In the endoplasmic reticulum, it also acts like a built-in quality-control partner, supporting proper protein folding and helping prevent misfolded proteins from accumulating.
Endoplasmic reticulum dysfunction has been linked to a wide range of diseases, including neurodegeneration and cancer. By linking endoplasmic reticulum health to the handling of oxidized glutathione, the study suggests that glutathione regulation may be a foundational part of keeping cellular protein production on track.
Glutathione Key Benefits for Vision
Cataract Prevention
Glutathione is crucial for maintaining lens clarity, and glutathione levels can decline quickly with age, often before cataracts develop. Studies suggest that supporting glutathione status may help defend against cataract formation.5 The lens naturally contains high levels of antioxidants, including ascorbic acid (vitamin C) and glutathione, which work together to help keep the lens clear.
A cataract is the loss of transparency in the normally clear eye lens. Lens opacification is the leading cause of blindness worldwide and is estimated to account for about 40% of total blindness.6 Oxidative stress is considered a major driver of age-related cataracts, and excess oxygen and reactive oxygen byproducts have been linked to increased cataract risk. For example, one study found that hyperbaric oxygen treatments can raise oxidative stress.7 Smoking and tobacco use also increase oxidative stress while reducing antioxidant defenses.8
Glaucoma Protection
Research shows that glutathione levels are significantly reduced in the aqueous humor of glaucoma patients, including both Normal Tension Glaucoma (where eye pressure stays within the normal range) and Primary Open-Angle Glaucoma (where eye pressure remains above normal). This makes glutathione an important protective factor, helping defend against oxidative damage to the optic nerve and supporting detoxification of the eye’s aqueous fluid.9 A considerable amount of evidence suggests that glutathione depletion is an important risk factor for glaucoma.
When aqueous fluid does not drain properly, intraocular pressure can rise. If increased intraocular pressure is not corrected, it can lead to vision loss over time, often beginning with peripheral vision.10 Reduced glutathione is associated with higher oxidative stress,11 which contributes to damage12 in the trabecular meshwork cells and retinal ganglion cells, worsening glaucoma and accelerating optic nerve damage.
Macular Degeneration (AMD)
People with macular degeneration have been found to have up to 58% lower glutathione levels than healthy individuals, and maintaining higher glutathione levels is associated with protection of retinal pigment cells from damage. Research also shows that several environmental and lifestyle factors can increase the risk of macular degeneration, including smoking, a high-cholesterol diet, carotenoid status, vitamins A and E levels, zinc levels, age, sex, and exposure to heavy metal ions and other chemicals.
The retina is especially vulnerable to oxidative stress due to its high oxygen exposure and high concentration of polyunsaturated fatty acids. Retinal pigment epithelial cells also generate reactive oxygen species, which can contribute to the formation and activity of advanced glycation end products. These compounds may damage cellular DNA and increase the expression of genes associated with retinal pigment epithelial cell aging.13 While reactive oxygen species are produced during normal daily metabolism, levels can also rise with prolonged exposure to ultraviolet and blue light-often associated with heavy use of screen-based devices such as computers and mobile phones.
The retinal pigment epithelium (RPE) performs a number of crucial functions, such as in the formation of an external retinal barrier, transport, retinoid retention, phagocytosis, the degradation of segmental photoreceptors, and protection against light and oxidative stress.14
Essential antioxidants help counteract the effects of oxidative stress include glutathione peroxidase and super oxide dismutase (SOD), which bind to antioxidants and neutralize the negative effects. The most important is glutathione.15. Postepy Hig Med Dosw (Online). 2007;61:438-453. PMID:17679914.] Most studies showed decreased GSH levels in AMD patients compared to people without the disease.16
Retinal Protection
Studies suggest glutathione protects retinal cells from oxidative damage. Further research indicates that it may help manage diabetic retinopathy by protecting retinal cells from damage.
Antioxidant Support
It works in tandem with other antioxidants, such as Vitamin C, to improve their stability, providing an added defense, for instance, in post-vitrectomy care.
Glutathione and Brain Health
Glutathione is the brain’s most abundant antioxidant. It plays a key role in protecting neurons from oxidative stress, supporting cognitive performance, and helping slow age-related cognitive decline. Unfortunately, glutathione levels tend to decrease naturally as we get older.
Research suggests glutathione may be reduced in the hippocampus in older adults, which can contribute to mild cognitive impairment, often seen in the early stages of Alzheimer’s disease.17 18 In addition, cell studies indicate Alzheimer’s disease may be linked with lower DNA methylation,19 and mitochondrial dysfunction is widely considered an important driver in Alzheimer’s disease development.20
Heavy metals such as mercury, arsenic, lead, and cadmium can also interfere with healthy brain function. Mercury, in particular, has been associated with increased amyloid beta buildup and neurofibrillary tangles-two hallmark features observed in Alzheimer’s disease. It may also impair glutathione’s ability to neutralize and help remove free radicals.21
Boosting Glutathione Naturally
By diet, consuming cruciferous vegetables like broccoli, cabbage, cauliflower, and Brussels sprouts helps increase glutathione production in the body. Garlic strengthens the immune system and boosts levels of natural glutathione,22 supporting working memory and cognitive capacity, slowing cholinergic cell death due to amyloid beta accumulation,23 and being neuroprotective. Resveratrol helps to prevent neurodegeneration caused by amyloid beta peptides24 by enhancing glutathione and consequently, antioxidant status.25
In Parkinson’s Disease (PD), Acetyl-l-carnitine is a precursor to glutathione, increases dopamine transporter density, and in PD patients has shown corresponding improvements in clinical outcomes.26
Alpha Lipoic Acid boosts glutathione levels and is a potent antioxidant, protects dopaminergic neurons in a Parkinson’s model, and decreases alpha-synuclein aggregation in the substantia nigra.27
Food sources: Good dietary sources that support glutathione include sulfur-rich foods, especially cruciferous vegetables like broccoli, cauliflower, and cabbage. Other great options include bok choy, kale, mustard greens, collard greens, radishes, turnips, and arugula.
As a supplement, glutathione is best taken in an intraoral or sublingual form as it is poorly absorbed in capsules or tablets. Glutathione can also be taken intravenously.
Supplements to Consider
ACG Glutathione EXTRA STRENGTH Spray 2oz. or ACG Glutathione EXTRA STRENGTH Spray 4oz. (currently on sale)
Dr. Grossman’s Complete Eye Formula 2oz (oral spray)
Dr. Grossman’s Complete Eye (oral Spray)/Meso Plus Combo Package
Mushroom Master Blend 84 caps (OM6720) – includes a broad range of mushroom extract including Lion’s Mane, Shiitake and Reishi mushrooms.
Dr. Grossman’s ReVision Formula (wild-crafted herbal formula) 2 oz – support healthy circulation and energy flow in the eyes and whole body, and supports healthy nerve function.
Advanced Eye & Vision Support Formula (whole food) 60 vcaps
Dr. Grossman’s Advanced Eye and Dr. G’s Whole Food Superfood Multi1 20 Vcap Combo – 2 months supply
NMN Wonderfeel Capsul 60 vegcaps
Dr. Grossman’s Premium Turmeric Vcaps (Organic)
Dr. Grossman’s Vitamin C Supreme (Plant-Based Formula) – 60 caps
Dr. Grossman’s Whole Food Organic Superfood Multi-Vitamin 120 Vcaps
AMD Package 1 (3-month supply)
Brain and Memory Support Package 1
Recommended Books
Natural Eye Care: Your Guide to Healthy Vision and Healing
Natural Parkinson’s Support: Your Guide to Preventing and Managing Parkinson’s
- Tanito M, Nishiyama A, Tanaka T, et al. Change of redox status and modulation by thiol replenishment in retinal photooxidative damage. Invest Ophthalmol Vis Sci. 2002;43:2392-2400. ↩
- Hanashima C, Namiki H. Reduced viability of vascular endothelial cells by high concentration of ascorbic acid in vitreous humor. Cell Biol Int. 1999;23:287-298. doi:10.1006/cbir.1999.0347. ↩
- Sacca SC, Izzotti A, Rossi P, Traverso C. Glaucomatous outflow pathway and oxidative stress. Exp Eye Res. 2007;84:389-399. doi:10.1016/j.exer.2006.10.008. ↩
- Liu S, Gad M, Li C, et al. SLC33A1 exports oxidized glutathione to maintain endoplasmic reticulum redox homeostasis. Nat Cell Biol. 2026. doi:10.1038/s41556-026-01922-y. ↩
- Bejarano E, Weinberg J, Clark M, Taylor A, Rowan S, Whitcomb EA. Redox Regulation in Age-Related Cataracts: Roles for Glutathione, Vitamin C, and the NRF2 Signaling Pathway. Nutrients. 2023 Jul 29;15(15):3375. doi: 10.3390/nu15153375 ↩
- Pascolini D, Mariotti SP. Global estimates of visual impairment: 2010. Br J Ophthalmol. 2011;96:614-618. doi:10.1136/bjophthalmol-2011-300539. ↩
- Borchman D, Giblin FJ, Leverenz VR, et al. Impact of aging and hyperbaric oxygen in vivo on guinea pig lens lipids and nuclear light scatter. Invest Ophthalmol Vis Sci. 2000;41:3061-3073. ↩
- Richter GM, Torres M, Choudhury F, Azen SP, Varma R. Risk Factors for Cortical, Nuclear, Posterior Subcapsular, and Mixed Lens Opacities: The Los Angeles Latino Eye Study. Ophthalmology. 2012;119:547-554. doi:10.1016/j.ophtha.2011.09.005. ↩
- Sato K, Saigusa D, Kokubun T, Fujioka A, Feng Q, Saito R, Uruno A, Matsukawa N, Ohno-Oishi M, Kunikata H, Yokoyama Y, Yasuda M, Himori N, Omodaka K, Tsuda S, Maekawa S, Yamamoto M, Nakazawa T. Reduced glutathione level in the aqueous humor of patients with primary open-angle glaucoma and normal-tension glaucoma. NPJ Aging. 2023 Nov 21;9(1):28. doi: 10.1038/s41514-023-00124-2. Erratum in: NPJ Aging. 2024 Jan 20;10(1):8. ↩
- Liesegang TJ. Glaucoma: changing concepts and future directions. Mayo Clin Proc. 1996;71:689-694. doi:10.1016/S0025-6196(11)63007-3. ↩
- Moreno MC, Campanelli J, Sande P, et al. Retinal oxidative stress induced by high intraocular pressure. Free Radic Biol Med. 2004;37:803-812. doi:10.1016/j.freeradbiomed.2004.06.001. ↩
- Flammer J, Haefliger IO, Orgul S, Resink T. Vascular dysregulation: a principal risk factor for glaucomatous damage? J Glaucoma. 1999;8:212-219. ↩
- Honda S, Farboud B, Hjelmeland LM, Handa JT. Induction of an aging mRNA retinal pigment epithelial cell phenotype by matrix-containing advanced glycation end products in vitro. Invest Ophthalmol Vis Sci. 2001;42:2419-2425. ↩
- Mitter SK, Song C, Qi X, et al. Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD. Autophagy. 2014;11:1989-2005. doi:10.4161/auto.36184. ↩
- Bilska A, Kryczyk A, Wlodek L. Rozne oblicza biologicznej roli glutationu [The different aspects of the biological role of glutathione ↩
- Sreekumar PG, Ferrington DA, Kannan R. Glutathione Metabolism and the Novel Role of Mitochondrial GSH in Retinal Degeneration. Antioxidants. 2021;10:661. doi:10.3390/antiox10050661. ↩
- Shukla D, Mandal PK, Ersland L, Gruner ER, Tripathi M, et al. Multi-Center Study on Human Brain Glutathione Conformation using Magnetic Resonance Spectroscopy. J Alzheimers Dis. 2018;66(2):517-532. ↩
- Shukla D, Mandal PK, Ersland L, Gruner ER, Tripathi M, et al. Multi-Center Study on Human Brain Glutathione Conformation using Magnetic Resonance Spectroscopy. J Alzheimers Dis. 2018;66(2):517-532. ↩
- Sung HY, Choi EN, Ahn Jo S, Oh S, Ahn JH. Amyloid protein-mediated differential DNA methylation status regulates gene expression in Alzheimer’s disease model cell line. Biochem Biophys Res Commun. 2011;414(4):700-705. ↩
- Swerdlow RH, Burns JM, Khan SM. The Alzheimer’s disease mitochondrial cascade hypothesis: progress and perspectives. Biochim Biophys Acta. 2014;1842(8):1219-1231. ↩
- Chakraborty P. Mercury exposure and Alzheimer’s disease in India – An imminent threat? Sci Total Environ. 2017;589:232-235. ↩
- Thorajak P, Pannangrong W, Welbat JU, Chaijaroonkhanarak W, Sripanidkulchai K, et al. Effects of Aged Garlic Extract on Cholinergic, Glutamatergic and GABAergic Systems with Regard to Cognitive Impairment in Abeta-Induced Rats. Nutrients. 2017;9(7):E686. ↩
- Nillert N, Pannangrong W, Welbat JU, Chaijaroonkhanarak W, Sripanidkulchai K, et al. Neuroprotective Effects of Aged Garlic Extract on Cognitive Dysfunction and Neuroinflammation Induced by beta-Amyloid in Rats. Nutrients. 2017;9(1):E24. ↩
- Li F, Kim MR. Effect of Aged Garlic Ethyl Acetate Extract on Oxidative Stress and Cholinergic Function of Scopolamine-Induced Cognitive Impairment in Mice. Prev Nutr Food Sci. 2019;24(2):165-170. ↩
- Nillert N, Pannangrong W, Welbat JU, Chaijaroonkhanarak W, Sripanidkulchai K, et al. Neuroprotective Effects of Aged Garlic Extract on Cognitive Dysfunction and Neuroinflammation Induced by beta-Amyloid in Rats. Nutrients. 2017;9(1):E24. ↩
- Afshin-Majd S, Bashiri K, Kiasalari Z, Baluchnejadmojarad T, Sedaghat R, et al. Acetyl-l-carnitine protects nigrostriatal pathway in 6-hydroxydopamine-induced model of Parkinson’s disease in the rat. Biomed Pharmacother. 2017;89:1-9. ↩
- Li YH, He Q, Yu JZ, Liu CY, Feng L, et al. Lipoic acid protects dopaminergic neurons in LPS-induced Parkinson’s disease model. Metab Brain Dis. 2015;30(5):1217-1226. ↩
