Oral supplements
Capsules and sachets, often combined with NAC or alpha-lipoic acid. Enteric and liposomal formats are formulator decisions — but they do not rescue a raw material that is already partly oxidised.
Fermented actives · Antioxidant
L-Glutathione (Reduced)
The body's principal intracellular thiol antioxidant, supplied as a reduced white powder at ≥99% — with the oxidation state documented, not assumed.
Also known as GSH · reduced glutathione · γ-Glu-Cys-Gly · glutathion
Overview
What glutathione is
Glutathione is a tripeptide of glutamate, cysteine and glycine, and the most abundant low-molecular-weight thiol in mammalian cells. As a bulk ingredient it appears in oral supplements, cosmetic formulations and cell-culture media — three applications with three different failure modes.
The commercial form is reduced glutathione (GSH). The oxidised dimer (GSSG) is its main degradation product, so the ratio between the two tells you more about a lot than the headline assay does. A material at 99% GSH with 1.5% GSSG has already begun to age; we report the oxidised fraction rather than leaving it inside an impurity total.
Eastling supplies reduced glutathione as a white crystalline powder at ≥99% by HPLC, packed to limit moisture and oxygen ingress in transit. Food and cosmetic grades share the same release specification — the difference is the documentation package, not the molecule.
- Reduced form, assay ≥ 99% by HPLC
- GSSG (oxidised fraction) reported separately
- Specific optical rotation confirms the L-configuration
- From 1 g evaluation samples to 25 kg drums
Identity
The record.
The identifiers your specification sheet, customs paperwork and product label all have to agree on. Where a number depends on the salt form, both are given.
- Chemical name
- γ-L-Glutamyl-L-cysteinylglycine
- Common name
- GSH; reduced glutathione
- CAS number
- 70-18-8
- Molecular formula
- C₁₀H₁₇N₃O₆S
- Molecular weight
- 307.32 g/mol
- INCI name
- Glutathione
- Appearance
- White crystalline powder
- Solubility
- Freely soluble in water; practically insoluble in ethanol
- HS code
- 2930.90 — indicative, confirmed per shipment
- Storage
- 2–8 °C, dry, protected from light
HS codes are indicative only. Final classification is confirmed per shipment with your customs broker.
Manufacture
How it is made.
Fermentation, not chemical assembly — which is why the impurity profile is dominated by the oxidised dimer rather than by synthesis by-products.
- 01
Fermentation
A high-yielding yeast strain accumulates glutathione intracellularly. The strain and the harvest point set the achievable titre and the colour of the final powder.
- 02
Cell harvest and extraction
Biomass is separated and disrupted; the aqueous extract is clarified before any purification step, because residual cell debris is what later shows up as haze in a customer's serum.
- 03
Ion-exchange purification
Glutathione is captured and eluted chromatographically, separating it from oxidised dimer and from other sulphur-containing cell metabolites.
- 04
Crystallisation and drying
Crystallisation under controlled temperature, then vacuum drying to the specified water content. Colour is graded here — a yellow cast is the visible sign of oxidation.
Applications
Where it is used.
Three formats account for most of the glutathione we ship. Each has a different stability problem to solve.
Skin care
Powders for serums and creams, usually buffered to pH 5–6.5. Colour drift is the usual complaint; it tracks oxidation, so ask for the GSSG figure before you blame the formula.
Cell culture & research
Reduced glutathione as a media supplement and as a standard in oxidative-stress assays, where the GSH/GSSG ratio is the actual measured variable.
Specification
Release criteria.
The written limits we release against, with the method used to test each one. Batch results for the lot you receive are stated on its certificate of analysis.
| Parameter | Limit | Method |
|---|---|---|
| Appearance | White crystalline powder, no visible discolouration | Visual |
| Assay | ≥ 99.0% | HPLC-UV |
| Oxidised form (GSSG) | ≤ 1.0% | HPLC |
| Identity | Consistent with reference | IR, LC–MS |
| Specific optical rotation | −15.5° to −17.5° (c=2, water) | Polarimetry |
| Water content | ≤ 0.5% | Karl Fischer |
| Heavy metals | ≤ 10 ppm | ICP-MS |
| Arsenic | ≤ 1 ppm | ICP-MS |
| Total plate count | ≤ 1,000 cfu/g | Plate count |
| Yeast & mould | ≤ 100 cfu/g | Plate count |
| E. coli / Salmonella | Absent | Enrichment |
| Shelf life | 24 months from manufacture, unopened | Stability programme |
Tighter limits — for example a lower heavy-metal ceiling or a residual-solvent panel — can be quoted against your own specification wording.
Certificate
Reading the certificate.
Glutathione is one of the few ingredients where the assay can be true and the material still be past its useful life.
The GSSG line is the real quality signal
Reduced glutathione oxidises to the dimer in storage. A lot at 99% GSH and 0.2% GSSG is fresh; the same assay with 1.9% GSSG has been warm or wet. Ask for the number, not the total impurity.
Titration flatters, HPLC does not
Iodometric titration is cheap and routinely reports 99%+ on material that HPLC puts at 97%. Our assay is HPLC with the method stated on the COA — compare methods before you compare numbers.
Optical rotation proves the L-form
Only the L-configuration is biologically relevant. Rotation outside −15.5° to −17.5° suggests racemisation or a different lot history, and it is a test many suppliers omit.
Documentation & packaging
What ships with it.
The paperwork travels with the goods. If your QA team needs an extra declaration, ask before the order is released — some are issued per production lot and cannot be retrofitted.
Certificate of analysis
Assay, GSSG, optical rotation, water, heavy metals and microbiological results, with the lot number on every page.
Analytical data
HPLC chromatogram showing the reduced and oxidised peaks separately, plus IR or MS identity.
SDS & specification
Safety data sheet for handling and transport, and the written specification used for release.
Declarations on request
Non-GMO, allergen, TSE/BSE and origin statements; kosher and halal documentation can be arranged where the production lot supports it.
| Pack size | Presentation | Typical use |
|---|---|---|
| 1–100 g | Amber glass vial | Evaluation and lab scale |
| 1 kg | Foil bag, desiccant | Pilot batches |
| 5 kg | Foil bag in carton | Small commercial |
| 25 kg | Fibre drum, food-grade liner | Bulk — quoted per order |
Questions
Before you order.
The questions buyers actually ask about Glutathione. Anything not covered here, ask directly — you will get an answer from someone technical, not a template.
Reduced or oxidised — which one do I need?
Reduced glutathione (GSH) is the form used in supplements and cosmetics. Oxidised glutathione (GSSG) is mostly a degradation marker; we report it rather than sell it as an equivalent. If your specification calls for GSSG as an ingredient, say so explicitly — it is a different product.
Why does my glutathione turn pink or smell of sulphur?
Moisture and oxygen ingress, not a different material. The powder is hygroscopic; opened drums in a humid room degrade within weeks. Store sealed at 2–8 °C and ask us for nitrogen-flushed foil if your climate or your warehouse is damp.
Is your assay HPLC or titration?
HPLC, with the method and column chemistry stated on the COA. This matters commercially: titration is the industry's cheapest test and the most generous one, and it will not show you the GSSG content at all.
Can I use the same lot for food and cosmetic products?
Usually yes — the release specification is the same and we issue both document sets. The distinction that matters is regulatory, not chemical: cosmetic use has different labelling and claims rules, and some markets restrict oral glutathione claims. Check with your regulatory advisor, not with us.
How does glutathione behave in a water-based serum?
It is freely soluble, but it oxidises readily above neutral pH and degrades with heat. Most formulators add it late in the cool-down phase and buffer to pH 5–6.5. If colour stability is critical, ask for the GSSG figure and run your own accelerated sample rather than relying on the raw-material COA.
What is the minimum order?
From 1 g for evaluation. Commercial lots usually start at 1 kg and are quoted with lead time by destination. Drums at 25 kg are the standard export pack.
Do you supply a food-grade version with a lower heavy-metal limit?
The standard specification is ≤10 ppm total heavy metals, which meets most food and cosmetic monographs. Tighter limits — for example ≤3 ppm, or a lead-specific limit — can be quoted against a defined test panel; send the exact wording from your specification.
How should I store it and how long will it keep?
Sealed at 2–8 °C, dry and dark: 24 months from manufacture. Once opened, reseal under nitrogen if you have it, keep the desiccant in the pack, and use within the period your own stability data supports.
Related
Often quoted together.
Quotation
Ask for Glutathione, by the gram.
Send the quantity, the grade you need and the destination. You will get a written quotation with lead time, packaging options and the documentation set for this material.