What it is
Glutathione is a peptide made of 3 amino acids: glutamate, cysteine, and glycine. Almost every cell in the body makes it. It is the most common antioxidant inside human cells. An antioxidant is a molecule that neutralizes reactive oxygen, a type of molecule that damages cells. The glutamate is joined by an unusual bond, which protects it from most enzymes inside cells. Outside cells, an enzyme called gamma-glutamyltransferase breaks it apart quickly. This makes it hard to raise glutathione levels from the outside. Other names: GSH, Reduced Glutathione, L-Glutathione.
What researchers study it for
- Absorption when swallowed, injected, or sprayed in the nose
- Drop in glutathione levels with age
- Parkinson's disease
- Skin lightening
- Oxidative stress markers in the blood
What the studies found
1. One large swallowed dose did not raise blood levels.
A 1992 study gave 7 healthy adults one large dose of glutathione by mouth. Blood levels of glutathione did not rise over 4.5 hours. Researchers concluded that the gut and liver break it down before it reaches the blood. Human data.
2. Daily doses for 6 months did raise body levels.
A 2015 trial gave 54 healthy adults glutathione by mouth daily, or placebo, for 6 months. Glutathione levels rose in blood cells, plasma, and cheek cells. The rise was bigger at the higher dose. Cheek cell levels rose 260 percent. Levels went back to normal 1 month after stopping. Human data.
3. When given by IV, it left the blood in about 14 minutes.
A 1991 study gave 10 healthy adults glutathione by IV. Blood levels spiked, then dropped by half in about 14 minutes. Blood levels of cysteine, one of its building blocks, rose sharply. This suggests the body mostly breaks it down into its amino acids. Human data.
4. Older adults made less glutathione. Its building blocks restored it.
A 2011 study found older adults made glutathione more slowly than younger adults. They also had more signs of oxidative stress. Giving them cysteine and glycine, two of its building blocks, brought glutathione production back up. Oxidative stress markers dropped. Human data.
5. A nose spray did not beat placebo in Parkinson's disease.
A 2017 trial tested a glutathione nose spray in 45 people with Parkinson's disease for 3 months. All groups improved, including placebo. Glutathione was not better than placebo. One person on the higher dose developed a heart muscle problem. Human data.
6. Skin lightening results were unclear.
This 2019 review found only 4 clinical studies. Swallowed and skin-applied glutathione lightened sun-exposed skin a small amount. Skin not exposed to the sun did not change. The reviewers called the evidence inconclusive because the studies were small and mixed in quality. This is a review, not new test data.
How much research exists
A very large body of lab research on how it works. Several small human studies on absorption and a few small trials. No large human trial has shown a health result.
Facts
- Formula: C10H17N3O6S
- Weight: about 307 g/mol
- CAS number: 70-18-8
- Sequence: gamma-Glu-Cys-Gly
- Time in the blood: about 14 minutes after IV
- Storage: powder in the freezer, away from light. Breaks down fast once mixed with water.
Legal status
Sold as a dietary supplement in the US. Not FDA approved as a drug for any use. In 2019 the FDA warned against injectable glutathione made from supplement-grade powder after its tests found bacterial toxins in samples.
For research use only. Not for human use. Nothing here is medical advice.