Research overview
Glutathione 400, 600 and 1500 mg: redox tripeptide in oxidative stress research
14 November 2026 · 5 min read
A tripeptide at the centre of the redox system
Glutathione, abbreviated GSH, is a tripeptide built from three amino acids: glutamic acid linked through its gamma carboxyl group, cysteine and glycine. It is written as gamma-Glu-Cys-Gly. The molecule has the formula C10H17N3O6S, a molecular weight of 307.3 g/mol and the CAS number 70-18-8.
The key element of this structure is the thiol group (SH) of the cysteine residue. It determines the ability of glutathione to donate electrons, and therefore its role in redox reactions. In cell biology, glutathione is one of the most studied molecules of its kind. It has been identified in cells of almost all aerobic organisms, mainly in the cytosol and mitochondria.
For teams working on oxidative stress, glutathione is a natural starting point. It allows you to compare the redox state of a culture with control values and check how the system responds to a stimulus. The reagent is supplied as a lyophilised powder with a purity of 99% or higher by HPLC, and its mass is confirmed by MS. You can find it on the Glutathione product page.
Reduced and oxidised forms: GSH versus GSSG
Glutathione occurs in the cell in two main forms. The reduced form (GSH) has a free thiol group and can donate electrons to reactive molecules. After such a reaction, two GSH molecules join through a disulfide bridge and form the oxidised form, GSSG.
In vitro, the ratio of GSH to GSSG is one of the basic indicators of redox state. A high share of the reduced form is usually described as a sign of normal function in cultured cells. A shift towards GSSG is often interpreted as a sign of growing oxidative stress. Such an interpretation requires care, because the result depends on the measurement method, the cell type and the culture time.
In practice, decide in advance which form you will measure, how you protect the sample from oxidation and when you will analyse it. Glutathione in solution oxidises gradually, so the time between preparing the solution and measuring it can change the result.
The enzyme system: GPx, GST and glutathione reductase
Glutathione rarely acts alone. Enzymology studies describe it together with three enzymes:
- glutathione peroxidase (GPx), which uses GSH to reduce hydrogen peroxide and lipid peroxides,
- glutathione S-transferases (GST), which in enzymatic models catalyse the attachment of glutathione to xenobiotics,
- glutathione reductase, which regenerates GSH from GSSG at the cost of NADPH.
These three form a cycle that the literature calls the GSH/GSSG cycle. Glutathione reductase keeps the pool of the reduced form in balance, and its activity depends on the availability of NADPH. For this reason, projects on oxidative stress often pair the glutathione measurement with an assay of enzyme activity.
Where glutathione appears in research
The literature mentions glutathione in several contexts that are worth keeping apart:
| Area | Typical model | What is measured |
|---|---|---|
| Oxidative stress | cell cultures | GSH to GSSG ratio, levels of reactive oxygen species |
| Redox signalling | cell lines | changes in the thiol state of proteins |
| Enzymology | enzyme preparations | activity of GPx, GST and reductase |
| Xenobiotics | in vitro liver models | conjugation of a substrate by GST |
| Animal models | rodents | markers of oxidative stress in tissues |
Glutathione has also been the subject of clinical studies. That part of the literature requires a separate, careful review and is outside the scope of this article. Here we focus on laboratory work with the reagent.
Planning an experiment with glutathione
A good project starts from the research question, and only then do you choose the reagent. Four questions help organise the work:
- Are you measuring the GSH content, the GSSG content or the ratio between the two?
- Which control groups will let you separate the effect from measurement noise?
- At what time and in which buffer will you process the samples?
- Do you need an enzyme activity assay alongside the glutathione measurement?
The answers affect the vial size. A smaller vial suits a pilot study. A larger one is useful in repeated series where you want material from a single batch. Glutathione is available in 400 mg, 600 mg and 1500 mg variants.
For many teams, quality control matters just as much. The purity of each batch is confirmed by HPLC (99% or higher), and the molecular mass by MS. This tells you that the vial contains the substance described on the product page.
What to control in culture
A glutathione measurement only makes sense inside a well designed experiment. In cell cultures, the result depends on cell density, medium composition, temperature and the moment the sample is collected. These factors can produce larger differences than the effect you want to study.
For this reason, run an untreated control, a vehicle control and samples collected at several time points in parallel. This helps you separate a change caused by the stimulus from the natural fluctuations that accompany cell growth. It is also worth recording the time from harvesting the cells to finishing the sample preparation, because that interval often decides how much GSH turns into GSSG before analysis.
When you interpret the results, consider several questions at once. Does the change affect the whole glutathione pool or only one form? Does it come with a change in enzyme activity? Does repeating the experiment on another day give a similar result? The answers will not replace a careful plan, but they show whether your conclusions are cautious and reliable.
Ordering and dispatch
Orders are dispatched within 24 hours. Parcels in Poland travel with InPost parcel lockers, and DPD delivers across Europe.
Working in the laboratory
Store the lyophilised vial at -20 °C, tightly closed and protected from light. Before opening it, let the vial reach room temperature so that moisture does not condense inside. Moisture speeds up degradation, and the thiol group oxidises easily.
Glutathione dissolves in water, including bacteriostatic water if you plan several withdrawals from one vial. Store the finished solution at 2-8 °C and avoid repeated freezing and thawing. Because it oxidises easily, it is best to prepare the solution just before use.
Calculate the working concentration in the concentration calculator before you start. This lets you record the exact amount of substance in your protocol and repeat the preparation under identical conditions.