Glutathione is amazing. Ever the underdog, few people have heard of this molecule, yet it supports nearly every aspect of our health. Consider these incredible properties:
- By acting as an antioxidant, it prevents wear and tear on your tissues, helping you stay youthful, age gracefully, and remain free of chronic diseases.
- By supporting every-day detoxification, it does far more to keep you toxin-free than any juice fast, herbal cleanse, or detox bath could ever do.
- By helping cells grow, multiply, and repair themselves, it supports growth in children, helps you heal after injury, and helps you get fit in response to exercise.
- In the lungs, it keeps mucus fluid, preventing congestion, and it opens up the airways, preventing asthma.
Although deep inside our cells we make our own glutathione every day, we also consume it in foods and it is available in supplements. This resource is a guide to consuming glutathione-rich foods and buying the right glutathione supplements. It ends with a searchable database of glutathione in 285 foods.
Can We Really Absorb Glutathione?
Some people may point out that glutathione can be broken down or oxidized in the digestive tract before absorption, making it useless to eat it in foods or use it as a supplement.
Although glutathione can indeed be broken down and oxidized before absorption, it can also be absorbed intact. Scientists have shown that oral glutathione is absorbed intact in laboratory animals, and that glutathione crosses human intestinal cells intact. They have identified some of the transporters involved, and have shown that oral glutathione increases glutathione status in both animals and humans.
Do Glutathione Supplements Need to Be Sublingual or Liposomal?
Unfortunately, we know very little about how the simpler, less expensive “regular” glutathione supplements compare to the fancier, more expensive sublingual and liposomal supplements. One study hinted at the possibility that sublingual glutathione improves glutathione status better than regular glutathione over the course of three weeks, but is it worth the extra cost?
Let's take the most generous interpretation of this study found in the marketing materials of Terry Naturally Clinical Glutathione, which claim 230% greater efficacy. This supplement costs $2.93 per gram of glutathione. By contrast, Jarrow Formulas Reduced Glutathione costs 60 cents per gram. Even if the sublingual form really were 230% better than the regular form, it's 488% more expensive. So, simple math shows that it's not worth it.
If we take a critical look at the study, sublingual glutathione looks even less impressive. See the technical notes below for a more detailed analysis.
Liposomal glutathione has the advantage of being packaged into liposomes. Liposomes are small droplets enclosed by membranes that are very similar to our own cellular membranes. These membranes shield their contents from digestion and allow them to be taken up by cells as entire droplets.
The case for liposomal glutathione rests on experiments using isolated cells. For example, liposomal glutathione is 100 times more effective at delivering glutathione to astrocytes, a particular type of brain cell. But these are isolated cells in a laboratory. When you consume liposomal glutathione as a supplement, do the liposomes all head straight to your astrocytes to be absorbed in tact? Beats me. There are, unfortunately, no human trials clearly documenting the superiority of liposomal glutathione to regular glutathione, and there is no way to perform a cost-benefit analysis.
Still, some people may benefit from liposomal glutathione for the following reason.
Glutathione appears to be taken up intact by the kidney, heart, lung, brain, small intestine, and skin. Nevertheless, it is possible that certain cell types lack the ability to take up glutathione intact, or that many cell types are not able to take up as much as they would need when exposed to stressful conditions. In healthy people, these cells will simply make their own glutathione. People with diabetes, insulin resistance, infection, or chronic inflammation, however, are not able to make as much glutathione as they should. Although poorly studied, liposomal glutathione may be preferable to regular glutathione for you if you suffer from any of these conditions. Additionally, carbohydrate restriction lowers glutathione synthesis, so liposomal glutathione may be helpful for you if you have poor glutathione status while consuming a low-carbohydrate diet.
Why Not Just Use N-Acetyl-Cysteine?
Glutathione is made from three amino acids: glutamate, cysteine, and glycine. In an average healthy person, the limiting amino acid for its production is cysteine. Cysteine itself degrades very easily, and N-acetyl-cysteine (NAC) provides cysteine in a way that prevents this degradation. While NAC is likely to be effective at supporting glutathione status in many people, glycine may be limiting in other people, and NAC doesn't provide any glycine. Further, people with any of the conditions that impair glutathione synthesis, listed in the paragraph above, will have a more difficult time using NAC to make their own glutathione. Glutathione supplements get around both problems.
What Is the Best Glutathione Supplement?
On the basis of cost and quality, I recommend Jarrow Glutathione. Here are four ways to buy it:
- The small bottle on Amazon. 60 500 mg capsules for $18.61. 62 cents per gram, eligible for Prime, ships from and sold by Amazon. Save an additional 5% by subscribing or an additional 15% by subscribing to five items.
- The big bottle on Amazon. 120 500 mg capsules for $36.00. 60 cents per gram, eligible for Prime, ships from and sold by Amazon. Save an additional 5% by subscribing or an additional 15% by subscribing to five items.
- The small bottle on iHerb. 60 500 mg capsules for $22.24. 74 cents per gram.
- The big bottle on iHerb. 120 500 mg capsules for $40.73. 68 cents per gram.
The best deal is the big bottle on Amazon.
People with metabolic disorders, chronic infection or inflammation, or who chronically restrict carbohydrate may find they respond better to liposomal glutathione. Core Med Science Optimized Liposomal Glutathione sells on Amazon for $41.99, providing 30 500 mg doses as a liquid, which is $2.79 per gram. The same brand sells a bottle of capsules providing the same number of doses for $46.99 and $3.13 per gram. iHerb sells Lypricel Liposomal Glutathione, which provides 30 450 mg packets for $59.95, which is $4.44 per gram, much more expensive than the Core Med Science product.
It is important to note that lipsomal glutathione tastes terrible and the liquid is a gooey syrup that does not mix well with anything. Core Med Science claims their capsules are tasteless. I cannot vouch for that, but I suspect most people would much rather take capsules than mix a nasty goo into their favorite smoothie, so I recommend the capsules for anyone who feels compelled to try liposomal glutathione.
Nevertheless, Jarrow glutathione is 4.5 times less expensive, so I recommend trying that first.
What Is the Best Dose of Glutathione?
Over the course of six months, both 250 mg and 1000 mg of oral glutathione have been shown to increase glutathione status in humans. The higher dose may be more effective than the lower dose, but we do not have sufficient data to make a rigorous comparison. See the technical notes below for a more detailed analysis.
As a prophylactic I believe a dose of 500 mg/d is likely to improve glutathione status when taken regularly over the course of several months.
How Do I know If I Should Take Glutathione?
Personally, I keep a bottle of Jarrow glutathione in my cabinet at all times, but I don't take it every day. If I get sick or am around sick people, I will take up to a gram per meal to support my immune system. If I develop any isolated respiratory symptoms such as wheezing, they tend to disappear rapidly if I take a gram of glutathione.
Although there are no clinical trials supporting these uses, 1 gram per day of glutathione for six months has produced no known adverse effects. Therefore, if 60 cents worth of glutathione might wipe out wheezing, why not try it? I believe this is a harmless form of first aid for non-emergency conditions.
There are two ways to determine whether you should use glutathione on a daily basis. First, if you know you have poor glutathione status. To determine your glutathione status, use the recommendations in Why You Should Manage Your Glutathione Status and How to Do It. Second, if you get sick often, feel you are aging too rapidly, or have a chronic disease.
While it is better to test than guess, testing can be expensive and glutathione supplementation appears harmless, so I think it is acceptable to self-experiment with supplements on the basis of symptoms alone, providing you do not use it as a substitute for professional medical treatment.
If any of these apply, I recommend trying one or two capsules of Jarrow glutathione per day. If these do not seem to give the desired result, try 500 mg of liposomal glutathione per day. If you find one to be better than other, please let me know in the comments!
Getting Glutathione From Foods
The food richest in glutathione are meats and vegetables. Fruits tend to occupy the middle tier, and most other foods are low in the glutathione. Processing such as canning and juicing degrades a large portion of the glutathione within a food.
Nevertheless, there is a lot of variation within categories, and I recommend searching our database for the foods you like to eat for a better view of what you are likely eating.
The database includes the following terms:
- Reduced glutathione. This is the fully functional form of glutathione you would get from a supplement.
- Total glutathione. This includes reduced glutathione and oxidized glutathione. Our cells regularly recycle oxidized glutathione back to its reduced form, so we can probably utilize the oxidized glutathione in foods.
- Glutathione-reactive substances. These are substances that can irreversibly degrade glutathione. They may diminish the availability of glutathione from foods, and eating foods that are rich in glutathione-reactive substances and poor in glutathione could even rob us of the glutathione we have made ourselves.
- Net glutathione. This is the total glutathione minus the glutathione-reactive substances.
Since we have not extensively studied the effect of consuming food glutathione on human health, it isn't 100% clear which term is best to use. The database sorts by reduced glutathione by default for two reasons: 1) this is the form found in supplements, so it is useful to compare what you would get from food versus supplements, 2) it has been measured in many more foods than net glutathione or glutathione-reactive substances has. Nevertheless, you can pick which term you want to sort by, and when you click on “view more details” for any given food, it will give you the complete information.
As an example of foods rich in reduced glutathione, consider the following:
Meat: one serving each of pork loin, chicken liver, and steak. 46.2 mg
Veggies: one serving each of asparagus, broccoli, and potatoes 46.3 mg
Fruit: one serving each of avocado, zucchini squash, and tomatoes 36.5 mg
You could eat all of these in a day, obtaining 130 mg of glutathione, and have room left over for plenty of other foods.
It is important to note that a food can be rich in glutathione and still bad for you. French fries, for example, are relatively rich in glutathione, but the high heat and fryer oil makes them a terrible food. A good diet is about more than glutathione. Still, glutathione is great! So check out the database to learn more about the glutathione you're consuming in your current diet.
The Glutathione Database
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Listen to the Podcast
This resource has a corresponding podcast, episode 40 of Mastering Nutrition: Why You Should Eat Glutathione. The podcast covers the topic of consuming glutathione in more detail, including an expanded view of why it survives digestion.
Other Searchable Nutrient Databases
Technical Notes About Glutathione Supplements
Comparing Sublingual Glutathione to Regular Glutathione
This was a randomized crossover study comparing N-acetyl-cysteine, reduced glutathione, and sublingual glutathione. Everyone underwent all three trials, and each trial lasted three weeks. During each trial, the subjects came in for measurements at the beginning, middle, and end. The most rigorous way to analyze the data is to look compare the ending value for each trial rather than the change during the trial. This is a protection against regression to the mean.
Using this approach, reduced glutathione was 8% higher after the sublingual trial than after the regular trial. The ratio of reduced glutathione to oxidized glutathione was 27% higher. To reach a 230% difference, the marketing materials of the sublingual product take advantage of the fact that the ratio of reduced glutathione to oxidized glutathione increased from 47.55 to 56.97 in the sublingual group but decreased from 51.68 to 44.76 in the regular group and compare the changes. This is not statistically sound. The fact that the ratio started off higher in the regular group than in the sublingual group means that it had more room to randomly fall while the sublingual group had more room to randomly rise. The principle by which randomly high things tend to fall down to the average and randomly low things tend to rise up to the average is called “regression to the mean,” and I've explained it in detail here.
If the ratio was 27% higher after sublingual glutathione and sublingual glutathione is 488% more expensive, then sublingual glutathione is 384% overpriced.
Comparing 250 mg to 1000 mg Oral Glutathione
The study that compared 250 mg to 1000 mg of oral glutathione reported most of its data as change from baseline, which, as described in the note above, is vulnerable to regression to the mean. Although a visual examination of the data does make it appear as though 1000 mg creates a larger effect that takes less time to kick in than 250 mg, there were no statistically significant differences between groups. Even if there were statistically significant differences between groups, we would not be able to rule out regression to the mean as a cause, since the absolute values for most measurements were not reported.
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