What is glutathione?

Cami Grasher
Oct 1
4 min read

Glutathione is a small protein made from three amino acids—glutamine, glycine, and cysteine. Thanks to its sulfur-containing structure, it acts a bit like a magnet, grabbing onto free radicals and toxins so your body can clear them out.

This cleanup crew is key for keeping oxidative stress in check. In simple terms, glutathione helps maintain a healthy balance between harmful molecules (reactive oxygen species, or ROS) and the antioxidants that neutralize them.

Some ROS are normal—and even useful—but when they build up, they can damage cells. Glutathione is considered the body’s “master antioxidant” because it’s central to keeping that balance.

How the "master antioxidant" earned its title

According to Lise Alschuler, N.D., FABNO, professor of clinical medicine at the University of Arizona, glutathione is the most prevalent and important cellular antioxidant. "Glutathione supports the redox potential within a cell, facilitating the cell's ability to quench oxidative stress and reset its antioxidative capacities,"* she explains.

In addition to glutathione's direct antioxidant properties, it also recycles vitamins C and E, which are powerful antioxidants in their own right.* No matter which toxins are thrown its way, glutathione has a knack for orchestrating its team of antioxidant players to ensure unwanted molecules are taken care of and oxidative balance is ultimately restored.*

Considering glutathione is found in every cell in the body, it's no secret that its free-radical-fighting capabilities are utilized universally.* However, the highest concentrations of glutathione are found in the liver and kidneys, suggesting the antioxidant is a key player in helping these organs' elimination process and removal of toxins from the body.*

Natural detoxification processes and pathways buffer us from daily biological and environmental stressors, and glutathione's role in the detoxification of various compounds (including mercury and certain persistent organic pollutants, notes Alschuler) is evident.*

In terms of whole-body well-being, healthy metabolic detoxification has positive outcomes for everything from immune function to longevity. Glutathione has certainly earned its "master" title, wouldn't you agree?

What depletes glutathione?

Glutathione isn’t endless—your body constantly uses and recycles it, and certain lifestyle and environmental factors can deplete your supply faster than you can replenish it.

Chronic stress, lack of sleep, excessive alcohol, smoking, exposure to pollutants or heavy metals, certain medications, and even intense, unbalanced exercise can all increase oxidative stress and tax your glutathione reserves.

Aging also slows production as well, making it even more important to support your body’s ability to rebuild this essential antioxidant.

How to increase glutathione levels

While glutathione is found in some foods, dietary sources are poorly absorbed by the body and do very little to improve glutathione status. That said, there are a number of nutrients you can eat to help support glutathione's production, retention, and regeneration.

"Glutathione requires nutritional building blocks, specifically three amino acids: cysteine, glycine, and glutamine. Therefore, ensuring healthy quality protein intake is essential," explains functional-medicine-trained clinician Deanna Minich, Ph.D., CNS, FACN, IFMCP.

Meaning: The foods below provide your body with the building blocks needed to make glutathione, but they aren't direct sources of the antioxidant.

Sulfur: This essential mineral is a critical component of glutathione synthesis. Garlic, onions, and cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, kale, and cabbage are all rich sources of sulfur.
Vitamin C: Similar to glutathione, vitamin C supports redox balance by restoring other antioxidants like glutathione and vitamin E (and acts as a potent antioxidant in its own right).* Some vitamin-C-rich foods include guava, red bell peppers, kiwi, and citrus fruits like lemons, limes, oranges, and grapefruit.
Selenium: Another essential mineral, selenium supports glutathione-related enzymes by increasing their expression and activity.* Some selenium-rich foods include beef, chicken, brown rice, and Brazil nuts.

Glutathione supplements increase levels of this antioxidant*

A groundbreaking 2015 clinical study from the European Journal of Nutritiondemonstrated that a specific form of oral glutathione supplement called Setria® can increase both blood levels and body compartment stores of glutathione when taken daily.*

"This clinical trial proves that key forms of glutathione are not only bioavailable but efficacious in positively impacting glutathione status in the body. These are hugely important findings, "* says Ashley Jordan Ferira, Ph.D., RDN.

"The methods of testing and specific knowledge of glutathione have increased over the years, making some of the older studies showing that glutathione was not absorbed controversial and almost obsolete," explains Danielle Citrolo, PharmD, VP of scientific & regulatory affairs at Kyowa Hakko USA.

Citrolo goes on to say that glutathione is a very unstable molecule that is rapidly removed from the blood and tissues, so it must be replenished daily. With Setria® glutathione, oral glutathione stores are improved thanks to proper absorption in the intestinal lining.*

"Older studies did not take into account the fact that multiple dosing may be required, as well as particular handling of the samples taken to test the glutathione levels," Citrolo explains.

Taking a supplement with 250 milligrams of glutathione—a clinically efficacious dose thanks to the current science—every day is a great way to promote sufficient glutathione levels and increase overall antioxidant activity in the body.*

Make sure to pair glutathione with these ingredients

For example, N-acetyl-L-cysteine, aka NAC can help promote glutathione production.* According to Alschuler, this targeted ingredients are especially helpful in increasing overall glutathione levels because cysteine is the rate-limiting amino acid (i.e., the slowest nutritional building block) in glutathione synthesis.*

When it comes to herbal bioactives, milk thistle contains a powerful free-radical scavenger phytonutrient compound called silymarin that has been shown to modulate glutathione-metabolizing enzymes and promote healthy redox balance.* Additionally, milk thistle supports the detoxification process by bolstering healthy liver function and protecting liver cells from toxins.*

The takeaway

Glutathione is an all-star antioxidant that fights against free radicals to promote redox balance and whole-body health. While it can be a challenge to maintain sufficient glutathione levels, a targeted supplements can provide the daily support your body craves.