SS-31: The Alternating Design

Proxiva Compliance DeskResearch-use standards and labelling

SS-31 is unusual in this catalogue for being a deliberately designed sequence rather than an endogenous molecule, a fragment of one, or a stabilised analogue of one. Its four residues alternate between aromatic and cationic character, and that alternation is the whole structural idea. This page covers what the design is for, how it compares to the other mitochondrially-associated compound here, and what its short length means for verification.

What is the alternating motif for?

Charge and aromaticity in a repeating pattern give a very short peptide properties that a random four-residue sequence would not have — specifically, the ability to associate with particular membrane environments. The cationic residues supply charge; the aromatic ones supply a different kind of surface. Alternating them produces a molecule whose two faces differ, which is a common design strategy for short peptides intended to interact with membranes rather than with a receptor pocket.

That is a structural description, not a claim about outcomes. What SS-31 has been shown to do belongs in the primary literature, and the searches at the foot of this page return it directly rather than through a summary.

How does it compare to MOTS-c?

They are grouped together constantly and share almost nothing structurally. MOTS-C is a sixteen-residue peptide encoded within mitochondrial DNA — an endogenous molecule with a genomic origin, which is itself unusual. SS-31 is a designed tetrapeptide with no natural counterpart.

The grouping is thematic. Both are discussed in mitochondrial contexts, which is enough for a catalogue heading and not enough for a mechanistic comparison. A result obtained with one implies nothing about the other.

On price the two are close — $8.00 against $7.00 per mg — which is unusual given the fourfold difference in length. Short peptides are generally cheaper per milligram, and the gap here being small rather than large is worth noticing.

What does a four-residue peptide need on its certificate?

Mass confirmation, and fill quantity. This is the same logic that applies to KPV – 10mg, a three-residue peptide: a synthesis this short is among the most reliable in any catalogue, and a badly assembled tetrapeptide tends to fail identity outright rather than pass as a near-miss. That means purity percentage — the number most prominently displayed — is answering the easier question.

The realistic failure modes for short peptides are a wrong molecule and a light fill. Both are detected by mass confirmation and quantitative fill determination respectively, and both are fields more often absent than a purity figure. Every batch sold here publishes its certificate on the test results page.

Handling

Unremarkable and standard. Shipped dry, stable at ambient temperature for transit, stored cold and dark long-term. Bring to room temperature before piercing the stopper. Reconstitute with Bacteriostatic Water where more than one withdrawal is planned — the preservative is the reason to prefer it over sterile water — adding diluent down the wall rather than onto the cake, and swirling rather than shaking. Peptides in solution are considerably less stable than as dry powder, so match the reconstitution volume to how quickly the vial will actually be consumed.

What separates suppliers on a page like this

Composition and price are easy to publish and easy to copy. Documentation is neither. The axis on which suppliers in this market genuinely differ is what their certificate reports and whether it is published per batch rather than as a specimen. A specimen certificate demonstrates that a laboratory once tested something; a per-batch certificate tells you about the vial in your hand.

The fields worth checking, in rough order of how often they are missing: quantity per component for any blend, the analytical method named rather than implied, the testing laboratory identified, an endotoxin determination, and a date that corresponds to the batch rather than to the listing. Every batch sold here publishes its certificate on the test results page.

Two further notes on handling that apply to every compound referenced above. Lyophilised material ships dry and tolerates ambient transit; long-term storage is cold and dark. Bring a vial to room temperature before piercing the stopper, because solvent entering a cold vial invites condensation. Reconstitute with Bacteriostatic Water where more than one withdrawal is planned — the preservative is the entire reason to prefer it over sterile water — adding solvent down the wall rather than onto the cake, and swirling rather than shaking.

Why a blend name is not a specification

Almost every named preparation in this market — Wolverine, Glow, Klow and the rest — originated in forum usage rather than in any standards body. Nobody registered the name, nobody defined it, and no authority polices it. The practical consequence is that two suppliers can both list a product under the same name and ship vials that differ by a factor of two or more in total mass and in the ratio between components.

This is why composition published elsewhere for these names frequently describes well under half the totals quoted here, and it is why comparing two vendors on price alone produces a meaningless answer. A cheaper vial carrying the same name may simply contain less. The only comparison that means anything is milligrams of each named component against price, taken from each supplier's own published composition — and where a supplier does not publish per-component quantities, there is no comparison to make.

The same logic applies to any review or ranking of these products that does not state composition. A page comparing five vendors' versions of a named blend without listing what is in each one is comparing labels, not materials.

Reading a certificate without taking it on trust

Most certificates in this market are genuine and most are also thinner than they appear. Four habits separate a document that means something from one that merely exists. First, check that the batch or lot number on the certificate matches the number on the vial — a certificate that names no batch is a specimen, and a specimen tells you a laboratory once tested something. Second, check the date: a certificate predating the batch it purports to describe is a filing error at best. Third, read what was actually measured. “Purity >99%” by an unnamed method is a claim; “99.2% by RP-HPLC at 214nm” is a measurement. Fourth, look for what is absent — mass confirmation, endotoxin, and for any metal-containing complex the metal determination itself.

None of this requires analytical training. It requires reading the document as a record rather than as a reassurance, and noticing which fields are populated. A supplier publishing per-batch certificates with named methods is making a checkable commitment; one publishing a single undated specimen is not.

What this page does not claim

Nothing here describes an intended use in humans, and no outcome of any kind is asserted. The material is supplied for in-vitro laboratory and research use only. Where a mechanism is described it is described as reported in the literature for that compound, and the searches below return that literature directly — including whatever currently contradicts the framing above. Proxiva does not curate those results.

Where to read the primary literature

Proxiva does not summarise findings on behalf of a researcher. These are live searches against the two public registries, not curated citations — they return whatever is currently indexed, including results that contradict the framing above.

• PubMed: SS-31 peptide · ClinicalTrials.gov
• PubMed: elamipretide · ClinicalTrials.gov
• PubMed: cardiolipin binding peptide · ClinicalTrials.gov
• PubMed: mitochondrial targeted peptide · ClinicalTrials.gov

Frequently asked questions

All materials listed are supplied strictly for in-vitro laboratory and research use. They are not drugs, foods or cosmetics, are not for human or veterinary use, and nothing on this page describes an intended use in humans. Figures quoted are catalogue list prices at the time of writing and change without notice.