Glutathione: 5 Science-Backed Benefits

Dr. Michael Murray, N.D.Posted on October 6, 2025

Key Takeaways

• Glutathione is a powerful antioxidant produced naturally in your cells, composed of three amino acids: glutamine, glycine, and cysteine.
• It protects cells from damage, neutralizes toxins, supports the immune system, and is essential for liver health.
• You can increase your body’s glutathione levels through specific foods, lifestyle choices, and targeted supplements like NAC.

‌‌‌‌What Is Glutathione?

Glutathione is a small protein molecule composed of the amino acids glutamate, cysteine, and glycine. It is one of the most important compounds that every cell in your body produces. 

‌‌‌‌What Does Glutathione Do?

Glutathione helps protect our cells from damage and aids in detoxifying harmful compounds. 

Over the course of 100 years of research, more than 100,000 scientific papers have established maintaining cellular glutathione levels as one of the most important keys in maintaining proper cellular function, immune health, and slowing the aging process. 

This article will explore the top evidence-based benefits and how to increase your levels.

‌‌‌‌5 Benefits Of Glutathione

1. It is an antioxidant. Glutathione is the cell’s major antioxidant to protect the cell from damage. It is also critical to the recycling and proper utilization of other antioxidants such as vitamins C and E.
2. It has immune system effects. Glutathione protects immune cells from damage while also exerting some direct antiviral effects. It is also critical in modulating balance within the immune system. It boosts functions when the immune system is underactive and brings it back into balance when it is overactive.
3. It has mitochondrial effects. Glutathione plays a critical role in the function of mitochondria (the energy-producing compartments in cells). 
4. It is critical to cellular function. Glutathione is required for the manufacture of many cellular proteins, the synthesis and repair of DNA, the activation and regulation of cellular enzymes involved in overall cell function, and the proper action of vitamin D3.
5. It is a detoxifying compound. Glutathione is the body’s most effective detoxifying agent. Glutathione binds undesirable toxins, pollutants, chemicals, heavy metals, and drug metabolites and excretes them through the urine or the gut.

Glutathione Deficiency

Glutathione levels tend to drop as we age, as well as when we are exposed to toxins, drugs, environmental pollution, and any other compound that causes oxidative damage. 

Low levels of glutathione are linked to accelerated aging and almost every chronic disease, especially those associated with aging, like cognitive decline, type 2 diabetes, and many forms of chronic disease.^1,2

Being older is a well-recognized risk factor for severe illness, complications, and death from a variety of causes, including viral infections. Lower glutathione levels make cells more susceptible to oxidative damage. Low glutathione levels can also impair the immune system as well as the protective barriers in the respiratory and gastrointestinal tract. 

Sources Of Glutathione Levels

Glutathione Foods

Diet can help raise glutathione levels, but only to a limited extent. The human body, mainly the liver, makes about 8,000 to 10,000 mg of glutathione daily. To put this amount into perspective, a healthy diet rich in fresh fruit and vegetables may provide about 150 mg of preformed glutathione per day. That said, the cell strives to hang on to glutathione, so the cumulative effects of higher dietary glutathione intake are certainly an important goal. Asparagus, avocado, and walnuts are particularly rich dietary sources of glutathione. 

Glutathione Supplements

The most popular supplemental approaches to boost glutathione levels involve taking either glutathione or N-acetylcysteine. Prior to recent studies, there was some controversy with glutathione as a dietary supplement because it was thought that glutathione may not be absorbed when taken orally. One early study is often cited to show a lack of absorption. In the study, a single dose of 3,000 mg of glutathione failed to increase glutathione levels in the blood. However, it turns out there is another reason.⁷ Researchers were looking for free glutathione levels, and because glutathione is so valuable, it is quickly bound to transport proteins to be carried to cells⁸, causing it to not show up as free glutathione in the blood. 

Frequently Asked Questions About Glutathione

What role does glutathione play in immune health?

Glutathione is critical for a healthy immune system, and research shows that higher levels are linked to a proper response to viral infections. It supports immune function in several key ways:

• It protects immune cells from damage while enhancing their ability to fight viruses.^3-5
• It has shown direct effects in blocking viruses from replicating at various stages of their life cycle.^3-5

Is it better to take glutathione or NAC?

Choosing between glutathione and N-acetylcysteine (NAC) depends on your specific health goals, as both offer significant clinical benefits. While the choice can be like “splitting hairs,” there are key differences in how they work.

Advantages of Glutathione:

• It is the preformed, active compound. When you take a glutathione supplement, your body is getting the complete, ready-to-use “master antioxidant.”

Advantages of NAC (N-Acetylcysteine):

• It provides the key building block for your body to produce its own glutathione. NAC is a form of the amino acid cysteine, which is essential for glutathione synthesis.
• It offers
   targeted respiratory support. NAC is particularly helpful in protecting the lungs and gastrointestinal tract from damage.
• It is a powerful
   mucus-modifying agent (mucolytic). This makes NAC a better choice when dealing with thick, sticky mucus associated with acute or chronic lung conditions.

‌‌‌‌Can glutathione supplements be absorbed orally? 

Yes, while this was once a topic of debate, recent clinical studies have confirmed that glutathione can be effectively absorbed orally when taken as a supplement. Older studies often missed this effect because they failed to measure glutathione that travels through the blood bound to proteins. Here’s what the research shows:

• A groundbreaking 2014 study found that oral supplementation significantly increased the level of protein-bound glutathione in the blood, explaining the shortcomings of previous absorption studies.
• A 2015 Penn State study confirmed this, showing that taking 250 mg to 1,000 mg of glutathione daily for six months significantly increased glutathione levels in whole blood, red blood cells, and even cheek cells.
• A 2018 animal study further detailed the process, showing that glutathione is
   absorbed in the intestine and transported to the liver and other parts of the body for use.

How long does it take for glutathione supplements to work?

Like many antioxidants, glutathione starts working almost immediately in protecting cells against oxidative damage. But it will take one to two weeks for this protection to translate into noticeable benefits in improved antioxidant status. And for people with existing oxidative stress or metabolic challenges (e.g., diabetes, metabolic syndrome), it may take two to three months or more to see consistent improvements in antioxidant status.