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L-Glutathione vs. Glutathione: What’s the Difference?

L-Glutathione vs. Glutathione: What’s the Difference?

Glutathione is a powerful antioxidant produced in your body from three amino acids: L-cysteine, glycine, and L-glutamate. Both L-glutathione and glutathione refer to the same tripeptide compound. There is no difference between L-glutathione and glutathione. Many molecules have an “L” and an “R” form, which denote their stereochemistry. This is not the case for glutathione. It has no specific “L” and “R” forms.

In what forms does glutathione exist?

Free radicals are unpaired electrons that are produced during the process of cellular metabolism. Molecules with an unpaired electron are reactive and look for another molecule with an unpaired electron to bind to. Antioxidants, such as glutathione, donate electrons to free radicals. When all of their electrons are paired, the molecule is in a lower energy state and less reactive.

Glutathione exists in an oxidized form (GSSG) and a reduced form (GSH).

Glutathione’s reduced form (GSH):

  • Carries an extra electron (hydrogen)
  • Donates hydrogen (electron) to inflammation-causing free radicals to neutralize their effect
  • Glutathione peroxidase enzyme
  • Requires selenium
  • Converts two hydrogen peroxides into two water molecules

Glutathione’s oxidized form (GSSG):

  • State of glutathione after losing its electron
  • Forms a disulfide bridge between two glutathione molecules
  • Glutathione reductase enzyme

Glutathione can be recycled back to its reduced form using NADPH (reducing agent, electron donor). The ability to recycle oxidized glutathione to reduced glutathione is impaired when your body is under chronic stress.3 The ratio of oxidized (GSSG) to reduced glutathione (GSH) can provide an estimate of oxidative stress and its impact on your health.1

healthy foods

Are glutathione and L-glutathione the same?

Yes, glutathione and L-glutathione are the same molecules.

What is the best form of glutathione to take?

Because glutathione is a tripeptide, it is easily broken down into its component amino acids in the stomach and small intestine. Your body can produce glutathione if you consume sufficient quantities of its precursors, especially cysteine, methionine, glutamate, and glycine. The hardest amino acid to maintain sufficient levels is cysteine. To do so, consume foods high in methionine.

Cysteine and methionine are rapidly depleted when your body’s sulfur needs are high. Sulfur is needed in phase 2 detoxification reactions.

The more your body is exposed to toxins, the higher its sulfur demands, and if you do not consume enough sulfur-containing foods, your body’s cysteine and methionine stores may become depleted. A lack of cysteine and methionine can cause a lack of glutathione, allowing hydrogen peroxide molecules to accumulate. Hydrogen peroxide binds to cell membranes, damaging them and causing disease.

How can you maintain good glutathione levels?

Consume sulfur-rich foods

To preserve cysteine and methionine, consume foods rich in sulfur, including the following:

  • Beef
  • Broccoli
  • Brussels sprouts
  • Cauliflower
  • Fish
  • Garlic
  • Kale
  • Mustard greens
  • Onions
  • Poultry
  • Shallots
  • Watercress
A healthy diet for antiaging

Consume foods rich in glutathione precursors

Glutathione is made up of L-glutamate, glycine, and cysteine. Consume foods rich in these amino acids.


  • Eggs
  • Fish
  • Dairy
  • Meats


  • Red meets
  • Seeds
  • Turkey
  • Chicken
  • Pork
  • Peanuts
  • Cheese
  • Grains
  • Dairy products


  • Cheese
  • Sauces
  • Flavorings
  • Nuts
  • Processed meats
  • Fruits and vegetables
  • Seafood

Selenium is also important to maintaining glutathione. These foods are rich in selenium:

  • Baked beans
  • Beef
  • Brazil nuts
  • Brown rice
  • Chicken
  • Cottage cheese
  • Eggs
  • Fish
  • Ham
  • Organ meats
  • Pork
  • Sunflower seeds
  • Turkey

Supplement with N-acetylcysteine

N-acetylcysteine (NAC): NAC is a precursor to cysteine, a key glutathione component.

foods that are antioxidants

Consume foods high in antioxidants

Consume foods high in antioxidants. This will preserve glutathione levels in your body.  

Foods rich in antioxidants include:

  • Berries: blueberries, strawberries, raspberries, and blackberries
  • Dark chocolate
  • Nuts: pecans, walnuts, pistachios
  • Beans: kidney beans, black beans, pinto beans
  • Vegetables: spinach, kale, broccoli, Brussels sprouts, artichoke
  • Green tea
  • Spices: cilantro, cinnamon, turmeric, cloves
  • Tomatoes
  • Red wine

Avoid factors that deplete glutathione

Avoid factors that deplete glutathione levels, including these:3,4

  • A diet high in processed foods
  • Alcohol
  • Chronic diseases such as diabetes, heart disease, and cancer
  • Excessive or prolonged physical activity
  • Exposure to heavy metals
  • Exposure to pollution, radiation, and environmental toxins
  • Infections
  • Poor nutrition
  • Sleep deprivation
  • Smoking

Oral glutathione may not be an effective way to supplement glutathione, as digestive enzymes may break it down. Consume glutathione precursors and a wide range of colorful fruits and vegetables that are rich in antioxidants to increase your body’s glutathione stores.

If you would prefer glutathione injections as a way to bypass the digestive system and deliver glutathione directly to your body’s cells, talk to an Invigor Medical specialist to learn whether glutathione supplements are right for you.  

Buy Glutathione injections online.


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.


1. Shaik IH, Mehvar R. Rapid determination of reduced and oxidized glutathione levels using a new thiol-masking reagent and the enzymatic recycling method: application to the rat liver and bile samples. Anal Bioanal Chem. May 2006;385(1):105-13. doi:10.1007/s00216-006-0375-8

2.  Nimni ME, Han B, Cordoba F. Are we getting enough sulfur in our diet? Nutr Metab (Lond). 2007 Nov 6;4:24. doi: 10.1186/1743-7075-4-24. PMID: 17986345; PMCID: PMC2198910.

3. Kanagasabai T, Ardern CI. Inflammation, Oxidative Stress, and Antioxidants Contribute to Selected Sleep Quality and Cardiometabolic Health Relationships: A Cross-Sectional Study. Mediators Inflamm. 2015;2015:824589. doi:10.1155/2015/824589

4. Flora SJ, Mittal M, Mehta A. Heavy metal induced oxidative stress & its possible reversal by chelation therapy. Indian J Med Res. Oct 2008;128(4):501-23.

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Published: Jun 13, 2023


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