Glutathione (GSH)

In this study, 60 healthy medical students received either glutathione (500 mg daily) or a dummy treatment (placebo) for four weeks. The researchers measured the skin's content of the pigment melanin at six sites. In those who received glutathione, melanin fell at all sites, and the fall was statistically significant at two sites (the right side of the face and the left forearm). Both glutathione and placebo were well tolerated. The authors point out that long-term safety is not known and that larger studies are needed.

In this study, healthy women took either reduced glutathione (GSH), oxidised glutathione (GSSG) or placebo, 250 mg daily for twelve weeks. The researchers measured, among other things, melanin, wrinkles and skin properties. Both GSH and GSSG tended towards a lower melanin level than placebo, and GSH produced fewer wrinkles in some areas. Better skin elasticity was also suggested. No serious side effects occurred, and both forms were well tolerated.

In this study in Indonesia, 83 participants received either a dietary supplement containing glutathione, vitamin C, alpha-lipoic acid and zinc, or placebo, for twelve weeks. The researchers measured spots and skin tone with a skin analysis system. The supplement produced a somewhat greater reduction in certain measures than placebo, but the difference was not statistically significant. Only mild and transient side effects were reported. The authors conclude that the effect was limited and that more research is needed.

This review article examines how well and how safely glutathione works as a skin-lightening agent, taken as a tablet, applied to the skin or given into a vein. The authors describe how tablets can produce a clear but variable reduction in melanin with few side effects, while products applied to the skin give a good effect. Glutathione given into a vein acts quickly, but is associated with serious dangers such as anaphylactic shock and liver damage. They stress the need for large, thorough studies.

In this study, 34 patients with fatty liver (not caused by alcohol) first received three months of diet and exercise advice, then glutathione as a tablet (300 mg daily) for four months. After treatment, the liver value ALT fell clearly, and fat (triglycerides), free fatty acids and the iron marker ferritin were also lower. Those who responded best were younger and did not have severe diabetes. This was a small pilot study without a placebo group, so the results must be confirmed in larger studies.

This review article examines studies from 2014-2024 on glutathione (GSH) as a treatment for fatty liver not caused by alcohol. The authors looked at three studies with a total of 109 participants and found consistent improvements in the liver value ALT and lower levels of markers of oxidative stress. They point out that the studies were small and had different designs, so the results cannot simply be generalised to everyone. They call for larger and more thorough studies to confirm the effect and find the right dosage.

In this study, 125 older patients with type 2 diabetes received 500 mg of glutathione daily for six months in addition to standard diabetes treatment. The level of glutathione in the blood increased, and a marker of oxidative stress (8-OHdG) fell within as little as three months. In patients over 55, long-term blood sugar (HbA1c) was kept stable and fasting insulin increased. The researchers consider that glutathione may be a useful addition to diabetes treatment, particularly in older people.

In this study of 30 people with Parkinson's disease, the researchers investigated the safety of glutathione given as a nasal spray, at doses of 300 or 600 mg daily or placebo, over three months. After three months there were no significant differences between the groups in the number of side effects, and all groups tolerated the treatment. The researchers conclude that glutathione as a nasal spray appears to be safe and well tolerated in this group, and that further dose studies are warranted.

In this study of 45 people with Parkinson's disease, participants received glutathione as a nasal spray (100 or 200 mg) or placebo three times daily for three months. All groups, including the placebo group, improved over the period, but glutathione was no better than placebo. One participant in the high-dose group developed a heart muscle disease. The researchers consider that the results do not show nasal glutathione spray to be better than placebo, and that larger and longer studies are needed.

In this study, 54 healthy non-smoking adults received glutathione as a tablet (250 or 1,000 mg daily) or placebo for six months. The level of glutathione in the blood increased after just one month and continued to rise, most in the high-dose group. The researchers also saw signs of less oxidative stress and increased activity in certain immune cells (natural killer cells). Levels fell back to baseline after one month without supplementation. This showed for the first time that glutathione as a tablet can increase the body's stores.

In this pilot study, the researchers investigated whether a substance called gamma-glutamylcysteine (gamma-GC), taken as a single dose (2 or 4 grams), can raise the glutathione level inside cells in healthy people. They measured glutathione in white blood cells and found that the level rose to about two to three times baseline within three hours, before falling back towards normal after five hours. The researchers consider gamma-GC to be a form of cysteine that cells can take up directly. The study was small.

In this study, the researchers compared how well the body absorbs different forms of glutathione in 14 healthy adults. A new type (micellar glutathione, LMG) produced clearly higher levels of glutathione in the blood than ordinary glutathione, even at a lower dose. The ratio between reduced and oxidised glutathione was also better with the new form. In a 30-day follow-up it was well tolerated, with no changes in liver or kidney tests. The study was small, and the authors call for further research.