What Is Glutathione? Structure, GSH vs GSSG and What the Research Shows

What is glutathione, chemically? L-glutathione explained

Glutathione is gamma-L-glutamyl-L-cysteinyl-glycine, formula C10H17N3O6S, molecular weight about 307.3 g/mol. "L-glutathione" and "glutathione" name the same molecule: the L refers to the natural configuration of its amino acids, and it is the only form that matters biologically.

The detail that makes glutathione unusual is its first bond. Glutamate is attached to cysteine through its side-chain (gamma) carboxyl group rather than the usual alpha carboxyl. Ordinary peptidases do not recognise that bond, so glutathione survives inside cells at high concentration; only the enzyme gamma-glutamyl transpeptidase, on the outer surface of cells, breaks it down. The working part of the molecule is the thiol (-SH) group on cysteine, which donates electrons and binds to reactive compounds.

Cells make glutathione in two ATP-dependent steps. Glutamate-cysteine ligase joins glutamate and cysteine into gamma-glutamylcysteine, the rate-limiting step, and glutathione synthetase then adds glycine. Cysteine availability usually limits how much gets made, which is why cysteine donors such as N-acetylcysteine appear so often in glutathione research.

Reduced glutathione (GSH) vs oxidised glutathione (GSSG)

When two glutathione molecules give up electrons, their thiols join into a disulfide bond and form GSSG, oxidised glutathione (molecular weight about 612.6 g/mol). The enzyme glutathione reductase converts GSSG back to two GSH molecules using NADPH, so the pool cycles rather than being used up.

In healthy resting cells the GSH to GSSG ratio in the cytosol typically exceeds 100 to 1; under oxidative stress it can fall to 10 to 1 or lower. That is why the ratio is a common readout in oxidative stress research. When people search "reduced glutathione benefits", they are asking about GSH, the form our research vial contains.

What does glutathione do in the body?

Glutathione is for what, in plain terms? Its roles in cell biology fall into a few well-established groups:

• Antioxidant defence. Glutathione peroxidases, a family of selenium-containing enzymes, use GSH to reduce hydrogen peroxide and lipid peroxides to water and alcohols. GSH also regenerates vitamins C and E after they neutralise radicals.
• Detoxification. Glutathione S-transferases attach GSH to reactive electrophiles, drug metabolites and pollutants, making them water-soluble for excretion. The best-known example is paracetamol: in overdose, its reactive metabolite NAPQI exhausts liver glutathione, which is why N-acetylcysteine, a cysteine donor, is the standard antidote.
• Redox signalling. Proteins can be reversibly S-glutathionylated on cysteine residues, a modification that protects them from irreversible oxidation and switches their activity.
• Other roles. Storage and transport of cysteine, maintenance of mitochondrial redox state, and involvement in immune cell function are all documented research areas.

Glutathione benefits: what the research has actually tested

"Glutathione benefits" is one of the most searched phrases around this molecule, and most of what appears online overstates the evidence. The better question is what controlled studies have measured.

Can oral glutathione raise body levels? Results conflict. In a four-week study, Allen and Bradley (J Altern Complement Med, 2011) found that 500 mg taken twice a day left GSH, GSSG and their ratio unchanged. A longer trial by Richie and colleagues (Eur J Nutr, 2015) randomised 54 adults to 250 or 1,000 mg a day for six months and reported rises in blood glutathione at both doses; at six months the high-dose group's levels were 30 to 35% higher in erythrocytes, plasma and lymphocytes and about 260% higher in buccal cells. Duration and dose appear to matter.

Skin. Melanin index fell modestly and only temporarily in small trials of oral and topical glutathione. We cover these in detail in glutathione for skin: what the studies found.

What these studies do not show is that glutathione treats or prevents disease in healthy people. Low glutathione is associated with many conditions in observational research, but association is not evidence that adding glutathione changes outcomes. Tolerability data from the trials, and regulator warnings about injectable use, are in our glutathione side effects guide.

Glutathione in the laboratory

Reduced glutathione is a standard bench reagent: an antioxidant control in cell culture, a substrate for glutathione S-transferase and peroxidase assays, a reducing agent in protein refolding buffers, and a reference compound in oxidative stress models. AminoBlend supplies reduced L-glutathione as a 1,500 mg lyophilized vial; the sheer mass of powder is why it sits in a 10 mL vial. Identity (mass spectrometry) and purity (HPLC) are confirmed for each lot by an independent laboratory, and the printed lot number pairs with a certificate on our COA lookup page.

Two handling points specific to glutathione. It dissolves in water only to roughly 50 to 100 mg per mL, so the full fill will not go into solution at full strength inside the vial. And GSH in solution slowly oxidises to GSSG, so prepare only what a run needs, keep it at 2 to 8 °C and protect it from light. Our reconstitution guide covers technique, and bacteriostatic water or your method's buffer can be used as the solvent.

Buy Reduced L-Glutathione Online for Assay and Buffer Work

One 1,500 mg vial at $69 covers a great deal of bench work, which makes it good value for labs that use glutathione as a buffer component rather than a test compound. Buy it when your method needs reduced GSH specifically: the certificate confirms identity by mass spectrometry, and the handling notes above help stop it drifting toward GSSG once dissolved. Groups that study it next to copper peptides often buy GHK-Cu in the same order, and the 10 mL bacteriostatic water size suits the larger fill. Shop glutathione online from Australian stock and keep the sealed vial cold and dark until use.

Researchers working on skin biology often study glutathione alongside copper peptides in our skin and cellular peptides category. AminoBlend sells glutathione for laboratory research use only. It is neither a supplement nor a medicine and must not be used in people or animals.