Glutathione Oxidized (GSSG): Analytical Reference Standard and Redox-Active Ingredient
Glutathione oxidized (GSSG, CAS 27025-41-8) is the disulfide-bonded dimer of reduced glutathione (GSH). With a molecular weight of 612.63 g/mol, GSSG serves two distinct roles in the cosmetic and analytical fields: as a reference standard for measuring the GSH/GSSG redox ratio — a primary biomarker of cellular oxidative stress — and as a functional ingredient in specialized redox-cycling delivery systems. TCS NEXUS S.L. supplies analytical-grade and cosmetic-grade GSSG from our warehouse in Valencia, Spain under COSMOS. Water-soluble and stable across pH 3.0-7.0.
Redox Biology and Analytical Significance
The glutathione redox couple (GSH/GSSG) is the primary intracellular redox buffer in human cells. Glutathione reductase (GR) continuously recycles GSSG back to GSH using NADPH as an electron donor. In healthy cells, the GSH:GSSG ratio ranges from 100:1 to 400:1. A declining ratio indicates oxidative stress — this measurement is used in dermatological research to quantify UV damage, pollution exposure, and aging-related oxidative burden.
GSSG is required as a calibration standard for HPLC, enzymatic recycling assays (Tietze method), and LC-MS/MS quantification of glutathione redox status. Accurate GSSG quantification requires high-purity reference material to prevent artificial oxidation artifacts during sample preparation. In cosmetic R&D, measuring the GSH/GSSG ratio in reconstructed skin models (EpiDerm, MatTek) is standard practice for evaluating antioxidant efficacy of new active ingredients.
Beyond analytical use, GSSG has emerging applications in redox-responsive delivery systems. Disulfide bonds in GSSG can be reduced by intracellular glutathione, enabling triggered release of conjugated actives in the reducing environment of the cytoplasm. This approach is being explored for targeted delivery of retinoids and peptides in advanced formulation platforms.
Formulation and Usage Guide
For analytical reference standard use, GSSG is typically prepared as a 1-10 mM stock solution in phosphate buffer (pH 6.5-7.0) with 1 mM EDTA to prevent metal-catalyzed oxidation artifacts. Store aliquots at -20C and use within 24 hours of thawing. Typical quantities needed are 10-100 mg per analytical campaign.
For cosmetic formulation applications, GSSG is water-soluble and stable across pH 3.0-7.0. Add to the aqueous phase at 0.1-1% depending on the application. In redox-cycling formulations designed to support endogenous glutathione metabolism, pair with Glutathione Reduced (GSH) at a defined ratio to establish a controlled redox environment. Niacinamide (2-5%) supports NADPH regeneration, which fuels the glutathione reductase cycle that converts GSSG back to active GSH in skin cells. Compatible with most cosmetic ingredients; avoid strong reducing agents (sodium metabisulfite, DTT) in the same formulation as they will reduce GSSG to GSH prematurely.
Frequently Asked Questions
What is the difference between GSH and GSSG?
GSH (reduced glutathione) is the active, thiol-form antioxidant. GSSG (oxidized glutathione) is the disulfide dimer formed when two GSH molecules donate electrons to neutralize reactive oxygen species. Glutathione reductase enzymatically recycles GSSG back to GSH using NADPH. The GSH:GSSG ratio (normally 100:1 to 400:1) is the standard measure of cellular redox status.
Why would I use GSSG instead of reduced glutathione in a formulation?
GSSG is more oxidatively stable than GSH in aqueous formulations — GSH auto-oxidizes readily on exposure to air and trace metals. GSSG is used when you need a stable glutathione form for redox-responsive delivery systems, or when formulating a defined GSH/GSSG ratio for controlled redox environments. For direct antioxidant activity, Glutathione Reduced (GSH) is the appropriate choice.
What purity is required for analytical reference standard use?
HPLC and LC-MS/MS quantification of the GSH/GSSG ratio requires reference standards with purity above 98% to prevent measurement artifacts. TCS NEXUS S.L. supplies GSSG with full Certificate of Analysis including HPLC purity, residual solvents, and heavy metals data. Each lot is individually tested.
How should GSSG reference standard be stored?
Store dry powder at -20C protected from light and moisture. Prepared stock solutions (1-10 mM in phosphate buffer with EDTA) should be aliquoted and frozen at -20C. Avoid repeated freeze-thaw cycles. Use thawed aliquots within 24 hours for accurate analytical results.
What is the minimum order and delivery time?
TCS NEXUS S.L. offers 1 g evaluation quantities for analytical and formulation testing. Production MOQ is 100 g. All orders ship from Valencia, Spain with EU delivery in 5-7 business days. CoA and MSDS included with every shipment.
Product Specifications
| Parameter | Specification |
|---|---|
| INCI Name | Glutathione (oxidized form) |
| CAS Number | 27025-41-8 |
| Molecular Weight | 612.63 g/mol |
| Chemical Description | L-Glutathione oxidized (GSSG disulfide dimer) |
| Appearance | White to off-white powder |
| Solubility | Water soluble |
| Formulation Use Level | 0.1-1% (cosmetic); mg quantities (analytical) |
| pH Range | 3.0-7.0 |
| Primary Use | Analytical reference standard, redox-cycling formulations |
| MOQ | 1 g (evaluation), 100 g (production) |
| EU Delivery | 5-7 business days |
Related Ingredients
- Glutathione Reduced (GSH) — Active thiol-form antioxidant tripeptide for direct free-radical scavenging
- Ergothioneine — Histidine-derived thione antioxidant with complementary mechanism to glutathione system
Order Glutathione GSSG from TCS NEXUS S.L.
Request a 1 g evaluation sample for analytical or formulation work, or place a production order (MOQ 100 g). All orders ship from Valencia, Spain with EU delivery in 5-7 business days. Full technical documentation including CoA with HPLC purity data, MSDS, and storage guidelines provided. Contact our team for bulk pricing or custom specifications.