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Deutsch (EUR)What is glutathione? Composition, forms and S-acetyl-L-glutathione
KINGRAY ACADEMYWhat is glutathione? Composition, forms and S-acetyl-L-glutathione
Glutathione is a molecule that the body produces naturally. What is it made of, how do GSH and GSSG differ, and what is S-acetyl-L-glutathione? Explore the key terms and what supplement studies can—and cannot—tell us.
What is glutathione made of?
Glutathione is a tripeptide: a molecule made up of three amino acid components, glutamate, cysteine and glycine. Cells produce it through enzyme-controlled reactions.
It participates in maintaining redox balance, the balance between oxidation and reduction processes within cells. Its natural role in the body does not, by itself, demonstrate a benefit from taking a food supplement.
One of the three building blocks of glutathione.
Contains a sulphur atom that is important for glutathione’s chemical properties.
Completes the molecule’s three amino acid components.
What do GSH and GSSG mean?
GSH refers to reduced glutathione. During oxidation, two glutathione molecules can join through a disulphide bond to form GSSG, the oxidised form. The enzyme glutathione reductase enables GSSG to be converted back into GSH.
Researchers measure both forms and their ratio. The interpretation depends on the sample type, measurement method and health context. A measurement alone is not enough to establish a diagnosis or determine whether someone needs a supplement.
| Term | Meaning | How to interpret research |
|---|---|---|
| GSH | Reduced glutathione. | Findings depend on the preparation, dose and conditions studied. |
| GSSG | The oxidised form, consisting of two glutathione units linked by a disulphide bond. | A measured value needs to be assessed alongside other information. |
| S-acetyl-L-glutathione | A glutathione derivative with an acetyl group attached to the sulphur atom. | Findings from GSH studies cannot automatically be applied to this form. |
What is S-acetyl-L-glutathione?
S-acetyl-L-glutathione is a chemically modified form of glutathione. An acetyl group is attached to the sulphur atom in the cysteine part of the molecule. The name “S-acetyl” describes this particular chemical modification.
This modification changes the molecule’s properties. However, the name alone does not establish that a supplement is more effective, more readily utilised or suitable for everyone. Such conclusions require relevant evidence about the specific form and its use.
Glutathione and diet
The body produces glutathione from available amino acids. Protein obtained through a varied diet supplies building blocks for many bodily processes, including the production of the body’s own molecules.
The amount of a substance in a food or supplement does not allow a simple calculation of how glutathione levels will change in a particular tissue. Digestion, metabolism and the regulation of glutathione production and use all play a part.
What do glutathione supplementation studies show?
When assessing research, it is important to distinguish between a change in a laboratory marker and a demonstrated health benefit. Results depend on the form, dose, duration and participants studied.
A four-week study published in 2011
Allen and Bradley investigated oral glutathione supplementation in 40 healthy adults. Their randomised, double-blind, placebo-controlled trial found no significant changes in the measured markers of oxidative stress or glutathione status after four weeks. [2]
A six-month study published in 2015
Richie and colleagues studied 54 healthy, non-smoking adults. They reported increased glutathione levels in several types of samples during supplementation. The extent of the changes depended on dose, time and the material being measured. [3]
These studies investigated GSH, not S-acetyl-L-glutathione. Their findings cannot automatically be attributed to S-acetyl preparations. They also do not, by themselves, demonstrate disease prevention or treatment.
EFSA opinions, authorisation and health claims
In September 2026, an EFSA scientific opinion was published on the safety of S-acetyl glutathione as a novel food. The assessment relates to the ingredient described, its specifications, the population groups assessed and particular conditions of use. [4]
A scientific safety assessment does not, by itself, authorise a novel food to be placed on the market. Establishing its legal status requires checking the relevant European Commission authorisation and the current Union list of novel foods, including specifications, conditions of use, labelling requirements and any data protection provisions. [5]
Health claims are a separate matter. A conclusion about safety does not demonstrate a health benefit or automatically permit a health claim. Authorised claims and their conditions of use can be checked in the European Commission’s register and the relevant legislation. [6]
This article does not assess the legal status of any particular product or provide dosage recommendations.
Frequently asked questions
What is glutathione?
Glutathione is a tripeptide that cells produce from glutamate, cysteine and glycine. It participates in maintaining cellular redox balance.
What do GSH and GSSG mean?
GSH refers to reduced glutathione. GSSG is its oxidised form, consisting of two glutathione units linked by a disulphide bond.
Is S-acetyl-L-glutathione the same as GSH?
No. S-acetyl-L-glutathione is a glutathione derivative with an acetyl group attached to the sulphur atom in the cysteine part of the molecule. Findings from GSH studies cannot automatically be applied to this form.
Do increased glutathione levels prove a health benefit?
Not on their own. A change in a laboratory marker does not necessarily mean improved symptoms, disease prevention or treatment. It depends on which health outcomes the study actually assessed.
Does a positive EFSA opinion authorise a product for sale?
Not by itself. For a novel food, the relevant European Commission authorisation and the current Union list of novel foods must be checked, including the conditions of use.
References
- Labarrere CA, Kassab GS. Review of glutathione biochemistry and biological roles. Frontiers in Nutrition, 2022. Publication record on PubMed.
- Allen J, Bradley RD. Effects of oral glutathione supplementation on systemic oxidative stress biomarkers in human volunteers. Journal of Alternative and Complementary Medicine, 2011. Controlled clinical trial.
- Richie JP Jr et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. European Journal of Nutrition, 2015; first published online in 2014. Six-month controlled trial.
- EFSA NDA Panel. Safety assessment of S-acetyl glutathione as a novel food under Regulation (EU) 2015/2283. EFSA Journal, 2026;24(9):e10258. EFSA scientific opinion.
- European Commission: Union list of authorised novel foods.
- European Commission: EU Register of nutrition and health claims.
