Glutathione vs SS-31
Cellular
Glutathione
Endogenous thiol tripeptide and the principal intracellular antioxidant, central to redox buffering research.
Cellular
SS-31
Mitochondria-targeting tetrapeptide with high affinity for cardiolipin on the inner mitochondrial membrane.
Side by side
| Dimension | Glutathione | SS-31 |
|---|---|---|
| Molecular weight A 2.1× difference in mass — these are not comparable on a milligram-for-milligram basis. | 307.32 g/mol | 639.79 g/mol |
| Size class | small molecule / short peptide | short peptide |
| CAS number | 70-18-8 | 736992-21-5 |
| Research area | longevity | longevity |
| Sequence | γ-Glu-Cys-Gly | D-Arg-Dmt-Lys-Phe-NH2 |
| Available sizes | 750mg, 1500mg | 10mg |
| Entry price | $39 | $49 |
| Cost per mg Cost per milligram differs by more than 3×. Compare against the concentrations your protocol actually requires, not the headline vial price. | $0.05 | $4.90 |
Mechanism
Glutathione
Glutathione is a tripeptide with an unusual γ-peptide bond between glutamate and cysteine, which confers resistance to standard peptidase cleavage. Its free thiol group makes it the dominant intracellular redox buffer, and the GSH/GSSG ratio is a standard readout of cellular oxidative state. It is also an obligate cofactor for glutathione peroxidases and S-transferases.
SS-31
SS-31 is a cell-permeable tetrapeptide that concentrates in the inner mitochondrial membrane through interaction with cardiolipin, a phospholipid essential to cristae architecture and respiratory supercomplex assembly. Its alternating aromatic-cationic motif drives membrane targeting independent of mitochondrial membrane potential — a mechanistic distinction from earlier targeting strategies such as TPP+ conjugation.
Evidence quality
Mechanism is not the same as evidence. Where we have assessed the literature, the verdict is stated plainly.
Glutathione
Evidence base: vast for endogenous glutathione biology, thin for exogenous administration. The two should not be conflated. Bioavailability of the intact tripeptide is the open question, and gamma-glutamyl transpeptidase is the reason it is open.
Full research reference →SS-31
Evidence base: strong mechanism, well-characterised target, and a completed randomised controlled trial. The trial outcome should be read directly, since a compelling mechanism and a positive clinical result are separate things and this compound demonstrates the difference.
Full research reference →Research applications
Glutathione
- GSH/GSSG ratio measurement as an oxidative stress readout
- Glutathione peroxidase and S-transferase activity assays
- Xenobiotic conjugation and detoxification pathway studies
- Ferroptosis research (GPX4 dependence on GSH)
SS-31
- Cardiolipin binding and cristae morphology studies
- Mitochondrial respiration and ATP synthesis assays
- Reactive oxygen species and oxidative stress models
- Ischemia-reperfusion injury research
Common questions
What is the difference between Glutathione and SS-31?
Glutathione is endogenous thiol tripeptide and the principal intracellular antioxidant, central to redox buffering research. SS-31 is mitochondria-targeting tetrapeptide with high affinity for cardiolipin on the inner mitochondrial membrane. They differ in molecular weight (307.32 vs 639.79 g/mol) and in the pathways they are studied against.
Which is more cost-effective per milligram, Glutathione or SS-31?
Glutathione is lower at approximately $0.05 per milligram at its best tier, against $4.90 for the other. Cost per milligram is only meaningful relative to the concentrations a given protocol requires, since these compounds are not used at comparable masses.
Can Glutathione and SS-31 be studied together?
Combination designs appear in the published literature for a number of these compounds. Whether it is appropriate for a given protocol depends entirely on the model and endpoint. We supply research compounds and do not provide protocol guidance — consult the primary literature for your specific model.
How should Glutathione and SS-31 be stored?
Store lyophilized at -20°C protected from light. The free thiol oxidizes readily — minimize air exposure and prepare solutions fresh. For SS-31: Store lyophilized powder at -20°C protected from light. Reconstituted solution stable at 2-8°C for up to 30 days.
Which has the stronger evidence base?
Glutathione — Evidence base: vast for endogenous glutathione biology, thin for exogenous administration. The two should not be conflated. Bioavailability of the intact tripeptide is the open question, and gamma-glutamyl transpeptidase is the reason it is open. SS-31 — Evidence base: strong mechanism, well-characterised target, and a completed randomised controlled trial. The trial outcome should be read directly, since a compelling mechanism and a positive clinical result are separate things and this compound demonstrates the difference.
All products sold on this website are intended for research and identification purposes only. These products are not intended for human dosing, injection, or ingestion.
Comparison generated from Lyra Vital catalog data. Every specification is reconciled against the certificate of analysis for the shipped batch.