L-Glutathione

Note on the linkage

The bond between glutamate and cysteine forms from the glutamate side chain rather than its alpha carboxyl, which makes it a gamma linkage rather than a conventional peptide bond. That structural feature is why this molecule is not a substrate for the peptidases that would otherwise dismantle a tripeptide quickly, and why a dedicated enzyme, gamma-glutamyl transpeptidase, exists to cleave it. Any design assuming proteolytic behaviour typical of the peptides this molecule superficially resembles will be working from the wrong premise.

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The interactive verification record is shown below, followed by the same information reproduced as text on this page and the full certificate as a document. The record does not depend on the embed loading.

Certificate of analysis - lot GLUT-052026-2

Lot record

GLUT-052026-2

Results, this lot

Purity, content and endotoxin figures above are specific to lot GLUT-052026-2 and are not specifications carried across other lots. Each lot is tested individually and reports its own results.

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Glutathione exists in two interconvertible forms. The reduced form carries a free thiol on its cysteine residue and is the species of interest in essentially all of the literature. The oxidised form is two molecules joined through a disulfide bond: a different compound with different chemistry, roughly twice the mass, and its own registry number.

The conversion is straightforward and runs in one direction under ordinary handling. Air, alkaline pH and traces of transition metal all drive the reduced form toward the disulfide. Material stored carelessly, or a solution left standing, will contain more of the oxidised form than it started with, and a purity percentage on its own does not report the ratio.

The mass does. Reduced glutathione has a monoisotopic mass of 307.08 and appears at 308.09 as the protonated ion; the disulfide sits near 613. Those are not close together, and one look at the mass confirmation on the certificate for a given lot settles the question. On the lot above the observed ion is at 308.1, with a dimer adduct near 615 which is an expected artefact of two molecules associating in the source rather than the covalent disulfide. Check the certificate for the unit supplied rather than taking the form on trust.

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Panels differ between products and between lots. What follows is the scope of testing performed on this lot. Nothing is claimed unless it appears on the certificate for the lot supplied.

The first two entries in the right-hand column are the ones specific to this compound. The mass confirms which form predominates; it does not quantify how much of the other is present. Where that ratio is material to intended laboratory work, a thiol titration or a method resolving both species is the appropriate check.

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Preparation conditions are the responsibility of the receiving laboratory. Verum provides no protocol, no preparation instruction, and no guidance on use.

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That history is set out here because it is the clearest available answer to a question this market keeps getting wrong. The same committee, by almost exactly the same margin and again over its own reviewers, voted favourably on several research peptides in July 2026, and a great deal of writing since has treated those votes as though something changed. This substance is the four-year answer. A committee recommendation indicates direction, not timing, and it is not an approval of anything.

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Other listings in this catalogue carry an indexed bibliography. This one does not, for an unusual reason: the biochemistry of this molecule is textbook material rather than a contested literature. Its role as the principal low-molecular-weight thiol in the cell has been established for the better part of a century and appears in every general biochemistry course. There is nothing here to curate that a researcher does not already have.

The literature that is contested concerns administration to people, which is a separate question from what this compound does in a cuvette. We do not cite it, for the same reason we do not cite clinical work anywhere else in this catalogue.

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By placing an order you confirm each of the following:

Confirmation is recorded at checkout against your order. Verum reserves the right to decline or cancel any order.

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Orders placed before the daily cutoff are dispatched the same day from our United States warehouse. Domestic orders typically arrive within two business days. A tracking reference is issued by email once the consignment leaves the facility. Each unit carries a scannable code linking to the certificate for its own lot.

Not for human or veterinary use. Not for use in diagnostic or therapeutic procedures. This product is a laboratory reagent. Nothing on this page constitutes medical advice, a recommendation for personal use, or a representation that this material is safe or effective for any purpose. No statement here has been evaluated by the U.S. Food and Drug Administration.