Glutathione

What it is

Glutathione is a small molecule made of three amino acids (glutamate, cysteine, and glycine) that the body produces in nearly every cell. It's one of the body's main defenses against oxidative stress and helps the liver process many compounds.

How it works

Glutathione neutralizes reactive molecules, recycles other antioxidants like vitamins C and E, and helps the liver attach and clear certain drugs and toxins. The body makes it on demand, and cysteine is usually the limiting ingredient. Whether swallowed glutathione survives digestion well enough to matter has been debated — newer studies suggest some does, but the practical benefit remains unclear.

What it's been studied for

Commonly taken for antioxidant support, liver health, detox, and skin brightening.

What the evidence shows

Evidence is weak for real-world benefits: for years oral glutathione was thought to be broken down in the gut, and a four-week trial found no change in oxidative stress markers. A longer six-month trial did find daily oral glutathione raised glutathione stores in blood and cells, and a small liposomal study found similar increases. The key limitation is that raising levels hasn't been shown to translate into health outcomes people care about.

Who should consider it

People curious about antioxidant support who understand the evidence is early may reasonably try it. Most healthy people make enough of their own, and those hoping for detox, skin lightening, or disease-related benefits probably shouldn't bother, since those outcomes aren't established. People with liver disease or other conditions linked to low glutathione should work with their provider, who may consider options like NAC.

Amounts commonly studied

Studies typically used 250 to 1,000 mg per day of oral glutathione, including liposomal forms, for up to six months.

How to take it

Studies typically gave oral or liposomal glutathione once or twice daily, often on an empty stomach, for one to six months. If you're considering NAC instead, that's a separate supplement with its own studied doses and cautions. Talk to your provider if you have asthma, are on chemotherapy, or have a liver condition.

Forms & absorption

Standard capsules, liposomal liquids or capsules, sublingual forms, and S-acetyl glutathione are marketed as better absorbed, but head-to-head human data are limited. N-acetylcysteine (NAC) is a common alternative that supplies cysteine, the building block the body most needs to make its own glutathione.

Food sources

Asparagus, avocado, spinach, okra, and fresh fruits and vegetables contain some glutathione, though how much is absorbed is unclear. Protein foods that supply cysteine — eggs, poultry, dairy and whey, legumes — plus sulfur-rich garlic, onions, and cruciferous vegetables support the body's own production.

Safety & interactions

Oral glutathione is generally well tolerated; bloating or cramping can occur. Inhaled (nebulized) glutathione has triggered airway tightening in some people with asthma, and IV glutathione marketed for skin lightening lacks good evidence and carries infection and other injection-related risks. People undergoing chemotherapy should talk to their oncologist before taking antioxidants, and data in pregnancy and breastfeeding are limited.

Common questions

Is liposomal glutathione better absorbed?

It's designed to be, and a small study found it raised glutathione levels, but it hasn't been rigorously compared with standard oral forms. Better absorption also doesn't guarantee better results.

Should I take NAC instead?

NAC supplies cysteine, the building block the body needs most to make glutathione, and has more research behind it for certain uses. It has its own cautions, so it's worth discussing with your provider.

Will glutathione lighten my skin?

Evidence for skin lightening is weak, and IV glutathione for this purpose carries real risks. We don't recommend using it for that.