Glutathione: Forms, Research and Safe Use
Glutathione is a compound of three amino acids (glutamate, cysteine and glycine) that the body produces on its own. It takes part in oxidation and reduction reactions and in the metabolism of some substances in cells.1 However, the fact that glutathione is important for the body does not mean that everyone needs a supplement.
Glutathione is not a vitamin or a mineral, so there is no recommended daily intake for it. The EU has also not authorised any health claims for glutathione, whether about "detoxification", immunity or the skin.2
What is glutathione?
Glutathione exists in two forms: reduced (GSH) and oxidised (GSSG). The ratio between them reflects the oxidation-reduction (redox) balance of the cell.1
Most glutathione is found inside cells, for example in liver cells and red blood cells. There it takes part in various chemical reactions.
What do studies of glutathione supplements show?
Studies have mostly measured laboratory markers rather than how people feel or whether they become ill. Here are the main results:
- Standard glutathione, 6 months. Healthy non-smoking adults took 250 mg or 1,000 mg of glutathione per day. The researchers found changes in some glutathione markers, but did not assess disease or well-being.3
- Standard glutathione, 4 weeks. With 1,000 mg per day, the oxidative stress and glutathione markers studied did not change significantly.4
- Liposomal form. In a small study of a specific liposomal formula, some markers of blood glutathione levels changed. These results cannot be applied to other liposomal products.5
- Micellar form. In a study of 14 healthy adults, a micellar formula increased blood GSH levels more than the standard form. The long-term effect was not assessed.6
What forms of glutathione are found in supplements?
Supplements most often contain reduced L-glutathione. Products differ in form, excipients and other ingredients. It is worth knowing that better absorption does not necessarily mean a greater effect on health.
| Form or composition | Where it is most commonly found | What to know |
|---|---|---|
| Reduced L-glutathione | Capsules and tablets. | The most common form. How much is absorbed may differ between people and products. |
| Liposomal glutathione | Liquid products or capsules with phospholipids. | Liposomes are fatty vesicles that change how a substance enters the body. The long-term effect has not been studied.5 |
| Micellar and other special forms | Specialised products. | The results of a study of one product do not apply to all similar forms.6 |
| S-acetyl glutathione | A novel food; authorisation by the European Commission for the EU market is awaited. | In 2026, EFSA issued a positive safety assessment: up to 300 mg per day for adults, excluding pregnant and breastfeeding women. It will be allowed on the market only after a decision by the European Commission.7 |
| Glutathione precursors | Products containing N-acetyl-L-cysteine, glycine or other substances. | These are not glutathione, but substances from which the body makes it. |
| Multi-ingredient complexes | Blends with milk thistle, alpha-lipoic acid or vitamins. | The properties of the product depend on the whole composition, not on glutathione alone. |
Which form of glutathione is best?
There is no single best form. When choosing, look for a clear composition, the amount of glutathione per serving, and whether the product is compatible with other supplements and medicines you take.
How much glutathione should you take per day?
There is no official daily intake for glutathione. The table shows doses that were used in studies. It is a point of reference, not a recommendation: take the product as stated on its label.
| Where the dose was used | Amount | How to interpret it |
|---|---|---|
| Longer study of standard glutathione | 250 mg or 1,000 mg per day for up to 6 months. | Mainly laboratory markers were assessed.3 |
| Short study of standard glutathione | 500 mg twice a day, 4 weeks. | The markers studied did not change significantly.4 |
| Liposomal glutathione study | 500 mg or 1,000 mg per day, 1 month. | Few participants and a short duration.5 |
| S-acetyl glutathione safety assessment | Up to 300 mg per day for adults. | This is a safety limit, not a recommended dose.7 |
What are the side effects and safety of glutathione?
Studies of oral glutathione have mostly been small and short, so little is known about rare side effects or long-term use.
- Pregnancy, breastfeeding and children. In these cases, take a supplement only after consulting a doctor.
- Chronic conditions and medicines. If you have a chronic condition or take prescription medicines, consult a doctor or pharmacist before starting a supplement.
- Multi-ingredient products. Alpha-lipoic acid may affect blood glucose levels, so people with diabetes should consult a doctor. Milk thistle may cause an allergic reaction, especially in people who are allergic to plants of the daisy family.
- Injections and drips. An oral supplement and intravenous glutathione are not the same thing. Infusions are a medical procedure, so they should not be chosen on your own for skin lightening or "detoxification".8
When is the best time to take glutathione?
There is no evidence that a particular time of day is better. Unless the label says otherwise, take it whenever it is convenient and easy to remember.
Food and glutathione synthesis
To make glutathione, the body needs amino acids, which we get from protein-containing food. A varied diet with sufficient protein is therefore a good foundation.
| Food group | Examples | Practical significance |
|---|---|---|
| Protein sources | Eggs, fish, poultry, dairy products, legumes, tofu. | They provide cysteine, glycine and glutamate – the amino acids that glutathione is made of. |
| Vegetables and fruit | Spinach, broccoli, asparagus, avocados, citrus fruit. | Some of them naturally contain glutathione, but little research has been done on how much of it is absorbed from food. |
| Wholegrain and legume products | Oats, buckwheat, lentils, beans, chickpeas. | They add energy and plant protein to the diet. |
Selected supplements
Here are the glutathione supplements available in our shop. This is not an effectiveness ranking. Before buying, check the composition and instructions for use on the product page.
- Liposomal Glutathione, 500 mg – Osavi – glutathione in liposomal form.
- Glutathione with Milk Thistle Extract & Alpha Lipoic Acid, 500 mg – NOW Foods – glutathione together with milk thistle extract and alpha-lipoic acid.
Frequently asked questions
Is glutathione a vitamin?
No. It is a compound of three amino acids that the body produces on its own, so there is no recommended daily intake for it.
Does a glutathione supplement "detoxify" the liver?
No. Glutathione takes part in normal cell reactions, but a food supplement is not intended to "cleanse" the liver or treat liver disease. If you have liver problems, see a doctor.
Is liposomal glutathione absorbed better?
Small studies suggest that some liposomal formulas may increase blood glutathione levels. Whether this matters for health is not yet clear.5
Can glutathione be taken every day?
There is not much data on the long-term use of oral glutathione supplements. Follow the method of use stated on the product label and do not exceed the stated daily serving. If you take prescription medicines, have a chronic condition or plan to take the supplement for a longer period, consult a doctor or pharmacist.
Does glutathione lighten the skin?
Food supplements are not intended to lighten the skin, and the EU has not authorised such a claim. Pigmentation spots should be assessed by a dermatologist.8
When should you see a doctor?
If you feel persistently tired or have skin, digestive or liver symptoms, first find out their cause. A supplement will not replace a diagnosis.
Scientific and legal sources
- Wu G, Fang YZ, Yang S, Lupton JR, Turner ND. Glutathione metabolism and its implications for health. Journal of Nutrition. 2004;134(3):489–492.
- European Commission. EU Register of Nutrition and Health Claims.
- Richie JP Jr, et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. European Journal of Nutrition. 2015;54(2):251–263.
- Allen J, Bradley RD. Effects of oral glutathione supplementation on systemic oxidative stress biomarkers in human volunteers. Journal of Alternative and Complementary Medicine. 2011;17(9):827–833.
- Sinha R, et al. Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function. European Journal of Clinical Nutrition. 2018;72:105–111.
- Solnier J, Du M, Zhang Y, et al. A Targeted Metabolomic Assessment of Oral Glutathione Bioavailability and Safety in Humans: A Randomized Crossover Clinical Trial. Antioxidants. 2026;15(3):354. doi:10.3390/antiox15030354.
- EFSA NDA Panel. Safety of S-acetyl glutathione as a novel food pursuant to Regulation (EU) 2015/2283. EFSA Journal. 2026;24(9):e10258. doi:10.2903/j.efsa.2026.10258.
- Sitohang IBS, Ninditya S. Systemic glutathione as a skin-whitening agent in adult. Dermatology Research and Practice. 2020;2020:8547960.
