Does taking glutathione make sense, or is it broken down in your gut?

Glutathione is indeed partly broken down in the gut, but that does not mean taking it orally is pointless. A well-designed double-blind study in 54 healthy adults showed that six months of daily intake (250 or 1000 mg) clearly raised glutathione levels in the blood and cells. At the low dose (250 mg), levels in red blood cells and whole blood rose by 17 to 29%. At the high dose (1000 mg), the increase reached 30 to 35% in multiple blood cell types, and even up to 260% in buccal cells. That is measurable evidence that something does reach the body.

Moreover, the effect disappeared quickly once people stopped: one month after discontinuation, values had returned to baseline. That finding strengthens the idea that the rise was genuinely caused by the supplement, and not by chance. At the same time, the amount of oxidised glutathione in the blood fell, suggesting that oxidative stress decreased.

Less can be said about the practical significance of those higher levels. The study also measured the activity of certain immune cells, which more than doubled at the high dose after three months. But whether that means anything for how you feel or how healthy you stay cannot be determined from this research.

For skin lightening, a popular use of glutathione supplements, the evidence is even thinner. A review of four small studies found a trend toward reduced pigmentation in sun-exposed skin at 500 mg per day, but the researchers described the study quality as too low for firm conclusions. Effects on wrinkles and skin texture remained unproven.

Whether glutathione works as well as other ways of boosting the body's supply, such as through NAC (a building block for glutathione), cannot be compared on the basis of the available studies. That remains an open question.