The vast array of readily available supplements includes glutathione supplements. They’re found in the form of capsules, liquids and even transdermal patches. How efficient are they?

Glutathione and its role in the body

Glutathione (GSH) is a water-soluble tripeptide thiol with a low molecular weight. It can also be described as a non-enzymatic endogenous antioxidant. It’s the most numerous free radical scavenger in the human body. Glutathione is tasked with keeping cells and tissues resistant to deterioration and disease caused by oxidative stress, meaning damage made by reactive oxygen species (ROS). ROS are continuously formed through various biochemical processes, causing damage to cell lipids, proteins and DNA, preventing normal cellular functioning and causing many diseases such as carcinoma, hypertension, diabetes, atherosclerosis and premature aging. Other roles that glutathione fulfils include maintaining mitochondrial function and producing energy. It also takes part in the detoxification of endogenous metabolic products, like lipid peroxides, as well as xenobiotics, like pollutants, heavy metals and medicine. It also contributes to the immune system with its anti-inflammatory effect.


Due to the negative effects of oxidative stress, the goal is to keep antioxidants at a sufficient level in order to prevent or cure certain diseases. An enormous amount of supplements is available these days and that includes glutathione supplements.

One study has shown no significant increase in the total level of serum antioxidants following a 12-week oral intake of capsules containing 500 mg of L-glutathione, 250 mg of ascorbic acid, 50 mg of alpha-lipoic acid and 4 mg of zinc. Another study looking into the effect of oral supplementation containing only glutathione, with a dosage of 1000 mg every day over the course of 4 weeks, hasn’t noted an increase in serum concentrations of any form of glutathione. In other words, short-term supplementation of antioxidants, or at least glutathione, has no effect. Research conducted by Richie et al., (2015), has shown the effectiveness of long-term supplementation of glutathione, with a dosage of between 250 and 1000 mg a day throughout 6 months. An increase in glutathione levels was noted in plasma, erythrocytes, lymphocytes and buccal cells. However, concentrations returned to their previous levels after a month of no glutathione supplementation.

So far there hasn’t been any research that has demonstrated that glutathione supplementation can help prevent disease, but a lowered risk of oral carcinoma has been noted in individuals ingesting increased glutathione concentrations through food. Although some foods such as avocado, spinach, asparagus and okra are rich in glutathione, glutathione obtained this way has a low absorption rate. In fact, thermal processing and storage conditions lower the concentration of glutathione in food.

Side effects of glutathione supplementation

No serious side effects caused by glutathione supplementation were observed in the aforementioned studies. Changes in lab results (hematologic parameters, hepatic and renal function panels) were not noted. Some mild side effects were reported, such as flatulence, loose stools and temporary facial redness, with one person having also reported an increase in bodyweight.

Routes of administration

Intravenous administration was primarily used in clinical research. Glutathione inhalation is not recommended for patients with asthma due to a potential worsening of symptoms. Readily available glutathione supplements mostly come in the form of oral capsules or liquids, but transdermal glutathione patches for topical use can also be found.

How to actually increase glutathione concentrations

An alternate route to increasing glutathione concentrations is vitamin C supplementation, seeing as it will “attack” free radicals first, thus replacing glutathione and preserving it. An elevated concentration of glutathione in leukocytes has been demonstrated after supplementing vitamin C. Vitamin C also helps convert the oxidised form of glutathione to its active form.

It is recommended to consume foods rich in sulphur (beef, poultry, fish, broccoli, cauliflower, kale, garlic, onions) due to their ability to increase glutathione synthesis.


Translated by Anđela Jakiša



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