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Glutathione vs SS-31

Glutathione and SS-31 are studied in overlapping research areas, which is why they are frequently compared. This is a neutral side-by-side reference drawn from published preclinical literature and laboratory handling data.

Shared research areas:Cellular LongevityMetabolic
ClassEndogenous thiol tripeptide (γ-L-glutamyl-L-cysteinyl-glycine), reduced formMitochondria-targeting aromatic-cationic tetrapeptide (cardiolipin-binding)
Molecular weight307.3 g/mol639.81 g/mol
CAS number70-18-8Not assigned / not specified
Purity spec≥99%≥99%
Research areasCellular Longevity, MetabolicCellular Longevity, Metabolic
Primary diluentSterile water (USP grade)Bacteriostatic water (0.9% benzyl alcohol)
Working windowCommonly worked with for about 1 week at 2-8 °C; frozen aliquots keep longer.Commonly worked with for 3-4 weeks at 2-8 °C.
Lead degradation routeOxidation of the cysteine thiol to glutathione disulfide (GSSG, about 612.6 Da), catalysed by trace Cu²⁺/Fe³⁺ and faster at neutral-to-alkaline pH.Adsorptive loss to plasticware from the cationic charge — the main practical concern.
Freeze–thawTolerates a few freeze-thaw cycles, but each thaw exposes the thiol to dissolved oxygen. Aliquot once and thaw each portion only once.Tolerant; the unnatural residues resist degradation. Aliquot as standard practice.
Light sensitivityNot strongly light-sensitive, but oxygen-sensitive: minimise headspace and avoid metal spatulas or metal-contaminated buffers.No specific light requirement beyond normal practice.

How they actually differ

Comparing the two: Glutathione is endogenous thiol tripeptide (γ-l-glutamyl-l-cysteinyl-glycine), reduced form, while SS-31 is mitochondria-targeting aromatic-cationic tetrapeptide (cardiolipin-binding) — different molecular classes with different handling consequences; they call for different primary diluents (sterile water (usp grade) versus bacteriostatic water (0.9% benzyl alcohol)); their leading degradation routes differ (oxidation of the cysteine thiol to glutathione disulfide (gssg, about 612.6 da), catalysed by trace cu²⁺/fe³⁺ and faster at neutral-to-alkaline ph. for Glutathione, adsorptive loss to plasticware from the cationic charge for SS-31), so the storage precautions that matter are not the same; their practical working windows differ once reconstituted. The sections below set out each in full.

Glutathione — origin

Glutathione is the tripeptide γ-glutamyl-cysteinyl-glycine. The glutamate is joined through its side-chain (γ) carboxyl rather than the usual α link, which protects it from most peptidases. It was named by Frederick Gowland Hopkins in 1921, and its role in cellular redox chemistry was mapped out through the 20th century, most influentially in Alton Meister's work on the γ-glutamyl cycle.

SS-31 — origin

SS-31 (Elamipretide) is a Szeto-Schiller aromatic-cationic tetrapeptide (D-Arg-2',6'-dimethyltyrosine-Lys-Phe-NH2) that concentrates in the inner mitochondrial membrane and binds cardiolipin, the lipid unique to that membrane. Its structure is the reason it is studied specifically at the mitochondrion rather than as a general antioxidant.

Glutathione research themes

Cellular redox buffering (GSH/GSSG ratio)

Glutathione is the most abundant low-molecular-weight thiol in most cells, and the ratio of reduced to oxidised glutathione is widely used as a read-out of oxidative stress in cell-culture and tissue studies.

The γ-glutamyl cycle

Meister and Anderson (Annu Rev Biochem 1983) reviewed glutathione synthesis by γ-glutamylcysteine synthetase and glutathione synthetase, and its breakdown by γ-glutamyl transpeptidase — the framework most synthesis and turnover studies still use.

Detoxification by glutathione S-transferases

GSTs conjugate glutathione to electrophilic compounds, and this conjugation step is a standard model in xenobiotic-metabolism research.

The glutathione peroxidase system

Glutathione peroxidases use GSH to reduce hydrogen peroxide and lipid hydroperoxides, with glutathione reductase recycling GSSG back to GSH using NADPH — a common model for studying peroxide handling in vitro.

SS-31 research themes

Cardiolipin binding

Studied for selective association with cardiolipin in the inner mitochondrial membrane, the basis of its mitochondrial targeting.

Electron transport efficiency

Examined for effects on mitochondrial energy production in research models of mitochondrial dysfunction.

Oxidative stress

Investigated around reactive-oxygen-species handling at the mitochondrion.

Glutathione handling

  • Let the vial reach room temperature before opening to stop condensation getting in.
  • Use degassed diluent where possible and cap promptly after drawing.
  • Avoid metal tools and buffers with trace copper or iron; plastic or glass only.
  • Label aliquots with reconstitution date and diluent.

SS-31 handling

  • Reach room temperature before opening.
  • Use low-bind labware and buffers at low working concentrations to limit adsorption of the cationic peptide.
  • Aliquot and refrigerate.

Both third-party tested

Every Popular Peptides batch of Glutathione and SS-31 is independently tested by HPLC and LC-MS with a published Certificate of Analysis. Enter a lot number to pull the COA for a specific vial.

Glutathione reference

SS-31 reference

Related comparisons

Glutathione and SS-31 are supplied strictly as research chemicals for in-vitro laboratory and research use only. They are not intended for human or animal consumption, diagnostic, or therapeutic use. This comparison summarizes published preclinical literature and laboratory handling data; it is not medical advice, not a claim of efficacy, and not usage guidance.