Overview
In plain English
Glutathione is your body's main internal antioxidant — a three-amino-acid molecule your liver produces in large amounts and uses to neutralise damage and clear toxins.
It is used for antioxidant support, liver load, general recovery, and — the reason most people buy it — skin brightening and evenness of tone.
- What it isThe body's principal internal antioxidant, a tripeptide
- Mainly used forAntioxidant support, detoxification load, skin brightness and tone
- Typical protocol600mg per session, 2–3 times per week, 4–8 weeks
How it works
What it actually does
Glutathione neutralises damaging molecules by sacrificing part of itself, then gets recycled back to its active form. That cycle is running constantly in every cell.
It is also the body's main handle for grabbing toxins and drug by-products so they can be excreted — most of the liver's clearance work goes through it.
The skin effect comes from a separate action: it interferes with the enzyme that produces dark pigment and shifts pigment production toward the lighter type.

The science in detail
The structural detail that governs glutathione's biology is the gamma linkage. The bond to cysteine forms from the side-chain gamma-carboxyl of glutamate rather than its alpha-carboxyl, and conventional aminopeptidases cannot recognise it. The only enzyme that cleaves it is gamma-glutamyl transpeptidase, on the external face of the plasma membrane. Intracellular glutathione is therefore protected from proteolysis, while extracellular glutathione must be dismantled to its constituent amino acids and reassembled inside the cell — the gamma-glutamyl cycle described by Meister and Anderson (Annu Rev Biochem, 1983). Hence millimolar cytosolic concentrations against low micromolar in plasma.
Synthesis proceeds in two ATP-dependent steps. Glutamate-cysteine ligase, a heterodimer of catalytic and modifier subunits, forms the gamma-glutamylcysteine bond; glutathione synthetase then adds glycine. The first step is rate-limiting and feedback-inhibited by glutathione itself, with cysteine availability the usual substrate constraint. Transcription of both ligase subunits is under NRF2 control through antioxidant response elements, coupling glutathione capacity to oxidative and electrophilic stress (Lu, Biochim Biophys Acta, 2013).
Functionally the molecule works through its cysteine thiol. Glutathione peroxidases use it to reduce hydrogen peroxide and lipid hydroperoxides, generating the disulfide GSSG, which glutathione reductase reduces again at the cost of NADPH — a direct dependency on pentose phosphate pathway flux. Glutathione S-transferases conjugate it to electrophilic xenobiotics, initiating the mercapturic acid excretion pathway. Reversible S-glutathionylation of protein cysteines acts as a redox post-translational modification, reversed by glutaredoxins. Glutathione also recycles ascorbate and alpha-tocopherol and is the principal intracellular reservoir of cysteine.
Its relevance to pigment research runs through a separate route: glutathione inhibits tyrosinase, partly by coordinating the copper ions at the enzyme's active site, and its thiol reacts with dopaquinone to divert melanogenesis from eumelanin toward pheomelanin. Arjinpathana and Asawanonda (J Dermatolog Treat, 2012) examined oral glutathione against placebo in a randomised, double-blind trial measuring melanin index. Adjacent compounds differ: N-acetylcysteine is a cysteine precursor acting upstream of synthesis, and GSSG is the oxidised dimer rather than the active thiol.
Evidence
What the research shows
Your cells hold a thousand times more than your blood
Concentrations are millimolar inside cells versus low micromolar in plasma — supply is an intracellular problem.
Recycled, not used up once
It is continuously restored to its active form after neutralising damage.
Production is self-limiting
The rate-limiting enzyme is switched off by glutathione itself, so the body caps its own output.
Shifts pigment production
It inhibits tyrosinase and diverts melanin synthesis toward the lighter pigment type — the basis of the skin-brightening use.
Mixing & dosage
How to mix and dose it
These are the mixing and dosage instructions supplied by Purist Peptides and the manufacturer for this product.
A 3ml vial of bacteriostatic water is included free with every peptide vial you order, so you have what you need to mix this on arrival.
Glutathione 1500mg
Step 1 — mix your vial
- Draw up 5ml of bacteriostatic water into a syringe
- Wipe the rubber top of your vial with an alcohol swab and let it dry
- Insert the needle then slowly and carefully push the water down the inside wall of the vial — do not inject water straight onto the peptide powder
- Gently roll the vial between your palms until the powder dissolves completely
- Do not shake
- Allow to settle in the fridge for 5–10 minutes. The liquid should look clear
Step 2 — draw & inject your dose
Use a 1ml insulin syringe to draw and inject your dose. A 1ml syringe = 100 units.
With 5ml of water added, each 1ml (100 units) you draw = 300mg of Glutathione.
| Stage | Dose | On the syringe |
|---|---|---|
| Starting | 300mg per session, 2 to 3 times per week | 100 units (1ml) |
| Standard | 600mg per session, 2 to 3 times per week | 100 units x 2 injections (2ml total) |
Vial duration at standard dose (3x weekly at 600mg): approx 8 days
For the 600mg dose, split across 2 separate 1ml injections and rotate sites.
When to inject: Any consistent time of day. Rotate injection sites with each dose.
Cycle length: 4 to 8 weeks.
How to inject
- Wipe your injection site with an alcohol swab and let it dry
- Pinch a small fold of skin on your abdomen, thigh, or upper arm
- Insert the needle at a 45-degree angle into the pinched skin
- Slowly push the plunger down until empty
- Pull the needle out and apply gentle pressure with the swab
- Dispose of the needle safely in a sharps container — never recap or reuse
Storage
Keep refrigerated at 2 to 6 degrees Celsius at all times after mixing. Do not freeze. Protect from light and label the vial with the date you reconstituted it. Discard any solution that is hazy, discoloured or contains particles.
For informational purposes only. This is not medical advice. Speak to a qualified healthcare professional before starting any compound.

Questions
Frequently asked questions
What does the gamma linkage actually change?
It makes the molecule resistant to ordinary peptidases. Only gamma-glutamyl transpeptidase, an ectoenzyme on the cell surface, can break it. That single structural feature explains why intracellular glutathione persists at millimolar concentrations while circulating glutathione is rapidly dismantled.
How does glutathione differ from N-acetylcysteine?
NAC is a precursor, not a substitute. It supplies cysteine, the rate-limiting substrate for glutamate-cysteine ligase, and acts upstream of glutathione synthesis. Glutathione is the finished tripeptide and the direct cofactor for peroxidase, transferase and glutaredoxin systems.
What is the difference between GSH and GSSG?
GSH is the reduced form with a free cysteine thiol — the biologically active species. GSSG is the oxidised dimer, two glutathione molecules joined by a disulfide bond. The ratio between them is a standard readout of intracellular redox state, and glutathione reductase converts GSSG back to GSH using NADPH.
What is it studied for?
Research contexts include cellular redox buffering, phase II xenobiotic conjugation, protein S-glutathionylation as a signalling modification, hepatic oxidative stress models, and melanogenesis, where it inhibits tyrosinase and shifts melanin composition.
How is purity verified?
Every batch is assayed by Bioindustrial Services in Boksburg, an independent biotechnology laboratory, using HPLC. We do not self-certify. The signed certificate of analysis for each batch — lab number, method and assayed result — is published on our quality standards page.
How long does delivery take?
Orders are dispatched from within South Africa with tracking. Timelines by region and courier are set out on our delivery process page.
What is the returns policy?
Unopened vials in original condition may be returned within the stated window; full terms are in our refund policy.
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