What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epitalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
Reduced glutathione · tripeptide antioxidant
Overview
Glutathione (GSH) is a γ-glutamyl-cysteinyl-glycine tripeptide and the primary intracellular antioxidant in mammalian cells. Unlike standard peptides where the peptide bonds form between α-carboxyl and α-amino groups, GSH's first bond is between the γ-carboxyl of glutamate and the α-amino of cysteine, an unusual linkage that makes GSH resistant to typical peptidases and gives the molecule its characteristic stability and reactivity profile. The cysteine thiol is the redox-active site, cycling between reduced GSH and oxidized GSSG forms in response to cellular oxidative stress. GSH is studied extensively in hepatic detoxification, dermal pigmentation (via tyrosinase inhibition), and broader redox-balance research. PeptideXpo supplies reduced Glutathione (GSH form) at ≥99.0% HPLC purity. The molecule's free thiol is the major analytical and stability concern, GSH oxidizes readily to GSSG (the disulfide-linked dimer) on exposure to air, heat, or light, and the GSH/GSSG ratio is a quality-control marker for fresh material. The release packet specifies the GSH content as a fraction of total glutathione, plus residual solvents and water content. Large fill sizes (400-1500 mg) reflect GSH's typical use as an IV-infusion or compounded preparation at gram-scale doses rather than the μg/mg scales typical for peptide research products.
Who buys this, and why
Buyers for longevity-class peptides span research labs working on telomere, collagen, and circadian-rhythm models, plus cosmetic-formulation OEMs incorporating peptides like GHK-Cu into anti-aging finished products. Copper peptides in particular require attention to chelator-free water and EDTA-free buffers in downstream formulation work, incompatibility there is the most common cause of "the peptide didn't work" support tickets in this class.
Primary buyer fit: 503A / 503B compounding pharmacies, medical aesthetic clinics and med spas, and academic and contract research laboratories.
Specifications
Documentation available on request
Regulatory note
Sold for research and for use as a cosmetic ingredient where the receiving formulator's regulatory framework permits (e.g. EU cosmetic regulation 1223/2009, FDA cosmetic-monograph framework, equivalent regimes). Not a finished dosage form. Cosmetic-finished-product safety responsibility remains with the brand owner.
Frequently asked questions
GSH is the reduced form of glutathione with a free thiol on the cysteine residue; GSSG is the oxidized form where two GSH molecules are linked by a disulfide bond between their cysteine thiols. The reduced GSH is the biologically active antioxidant species; GSSG is the spent form generated as GSH neutralizes oxidative species. PeptideXpo supplies the reduced GSH form, but storage and handling matter, air exposure, heat, and light all drive GSH→GSSG oxidation, so the spec on a fresh batch is the GSH content as a fraction of total glutathione (target ≥98% GSH, ≤2% GSSG). Buyers should request the GSH/GSSG ratio on the COA and verify it independently if their downstream application is sensitive to the reduced form.
GSH is dosed in compounding pharmacy and med-spa contexts at gram-scale rather than the μg-mg scales typical for therapeutic peptides, a typical IV-infusion preparation contains 600-2000 mg of GSH per dose. The large fill sizes (400-1500 mg per vial) reflect this practical use case: compounding pharmacies and med spas need bulk material to support their preparation workflows, not the sub-100 mg fills appropriate for peptide research. Research-lab buyers using GSH in cell-culture or biochemical-assay work can typically use a fraction of the 400 mg vial; the remainder should be stored sealed under nitrogen at -20 °C to preserve the reduced form.
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