Glutathione is the tripeptide γ-L-glutamyl-L-cysteinylglycine — a routine reagent in enzyme assays, chromatography method work, and oxidative-stress biochemistry. It is also one of the easiest entries in a catalog to specify incorrectly, because the name covers two different substances.
The reduced form (GSH) is PubChem CID 124886: molecular formula C₁₀H₁₇N₃O₆S, average mass 307.33 g/mol, monoisotopic mass 307.0838 Da, CAS 70-18-8, ChEBI:16856. The oxidised disulfide dimer (GSSG, glutathione disulfide) is a separate record — PubChem CID 65359: C₂₀H₃₂N₆O₁₂S₂, average mass 612.6 g/mol, monoisotopic mass 612.1520 Da, CAS 27025-41-8, ChEBI:17858. Two molecules bridged at the cysteine thiols, minus two hydrogens — which is why the dimer mass is not simply twice the monomer.
This note is a research-context description only. It is not a claim of benefit, an account of any use in or on a person, and not a basis for any application outside the laboratory. Glutathione from Elev8 Labs ships as a laboratory reference standard.
Two records, one name
Getting this wrong is the most common specification error we see on inbound analytical questions:
- Molarity. A stock prepared against 612.6 g/mol when the vial holds the 307.33 g/mol reduced form is off by a factor of two.
- Identity by mass. An ESI-MS run looking for 307.08 will not find 612.15, and a partially oxidised lot shows both.
- The γ-linkage. The glutamate is joined through its side-chain carboxyl, not the α-carbon, so standard peptide-bond assumptions do not describe this molecule correctly.
- Thiol lability. GSH oxidises to GSSG in solution under air and at raised pH, which is why the COA date and the stated storage condition both matter.
Where glutathione appears in the research record
Published bench work using glutathione reference material spans:
- Redox-couple measurement — the GSH/GSSG ratio as a quantitative readout in cell lysates.
- Enzyme assays — glutathione peroxidase, glutathione reductase, and glutathione S-transferase systems, where glutathione is the defined substrate or cofactor.
- Analytical method development — RP-HPLC with thiol derivatization, and LC-MS/MS quantitation of both forms in a single run.
- Conjugation chemistry — glutathione adducts as a characterisation tool in electrophile screening.
That is a description of published methodology. It carries no interpretation about outcomes in humans.
Research-standard applications
Contexts in which researchers source characterised glutathione:
- Calibration curves for GSH and GSSG quantitation, where the standard's assigned content is the anchor for every reported number.
- System suitability — a well-behaved thiol peak for checking column performance and detector response before a sample batch.
- Stability studies — tracking the oxidation of GSH to GSSG under controlled buffer, temperature, and headspace conditions.
- Synthesis and sourcing comparison — benchmarking incoming material against an independently characterised lot.
Each of these happens at the analytical bench.
Lot-level quality requirements
Our glutathione reference material ships with:
- Purity by RP-HPLC, with the chromatographic conditions stated on the certificate
- Identity confirmed by mass spectrometry against the expected monoisotopic mass for the form supplied
- The form named explicitly — reduced (GSH) or oxidised (GSSG) — on vial, COA, and packing record
- Independent analytical COA, not self-certified
- Traceable lot number across vial, COA, and shipment record
The frameworks behind those lines are public. Area-percent purity is only comparable when the system suitability in USP General Chapter ⟨621⟩ Chromatography holds; identity by observed mass is framed in USP ⟨736⟩ Mass Spectrometry; and the method producing either number is validated against ICH Q2(R2), Validation of Analytical Procedures. Independence is checkable too — ISO/IEC 17025 accreditation is listed by NIST's NVLAP.
What is out of scope
Elev8 Labs supplies glutathione as an analytical reference standard and nothing else. It is not a consumer product, not a personal-care or ingestible product, and it is not packaged, labeled, or characterised for any use in or on a person. We do not answer questions framed around personal use. Our scope ends at the laboratory bench.
Analytical, method-development, and lot-availability questions are welcome at support@elev8labsrx.com.
Elev8 Labs products are reference standards for laboratory research only. Not for human consumption.