Oral Glutathione Does Reach Your Cells: A 6-Month Trial
The finding: Six months of daily oral glutathione raised glutathione levels in red blood cells, plasma and lymphocytes by 30 to 35%, and in cheek cells by 260%. Natural killer cell activity more than doubled.
Why this study mattered
For years the standard objection to oral glutathione was that it could not possibly work, because glutathione is a tripeptide and the digestive tract breaks peptides apart. The theory was reasonable. Nobody had properly tested it in humans over a meaningful period.
This trial tested it.
What they did
Researchers at Penn State College of Medicine ran a six-month randomised, double-blinded, placebo-controlled trial in 54 healthy non-smoking adults. Participants received either 250 mg or 1,000 mg of oral glutathione daily, or a placebo.
Rather than relying on a single blood marker, they measured glutathione in five separate compartments: whole blood, red blood cells, plasma, lymphocytes and exfoliated cheek cells. They also tracked oxidative stress and a panel of immune markers, and built in a one-month washout period at the end.
What they found
- Blood glutathione rose at 1, 3 and 6 months at both doses.
- At six months on the higher dose: up 30 to 35% in red blood cells, plasma and lymphocytes, and up 260% in cheek cells.
- On the lower dose: up 17% in whole blood and 29% in red blood cells.
- Increases were both dose-dependent and time-dependent. More glutathione and longer use meant higher levels.
- The ratio of oxidised to reduced glutathione fell, indicating lower oxidative stress.
- Natural killer cell cytotoxicity more than doubled against placebo at three months.
- After the one-month washout, levels returned to baseline.
What this means for you
The washout result is the most quietly convincing part of the whole trial. Levels climbed while people took it and fell back when they stopped. That is the pattern you would expect if the supplement were genuinely responsible, and it is hard to explain any other way.
Two practical points. First, this took time. Levels were still climbing at six months, and the increases were time-dependent. Glutathione is not a supplement that does its work in a fortnight.
Second, dose mattered. The 1,000 mg group saw substantially more movement than the 250 mg group across every compartment measured.
Worth knowing that this trial used standard oral glutathione, not a liposomal or microsomal preparation. Those delivery systems are designed to protect the molecule further on its way through the gut, so the question they answer is how much more efficiently the same job can be done.
The study
Richie JP Jr, Nichenametla S, Neidig W, et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. European Journal of Nutrition. 2015 Mar;54(2):251-263.
General information only. This is a summary of published research, not a therapeutic claim and not medical advice. A result found in a trial population is not the same as a product doing that for you. Always read the label and follow the directions for use. If you have a health condition or take medication, check with your health practitioner before use.
