PT-141 (Bremelanotide) vs SS-31
PT-141 (Bremelanotide) 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.
How they actually differ
Comparing the two: PT-141 (Bremelanotide) is cyclic heptapeptide, melanocortin receptor agonist, while SS-31 is mitochondria-targeting aromatic-cationic tetrapeptide (cardiolipin-binding) — different molecular classes with different handling consequences; their leading degradation routes differ (tryptophan photo-oxidation for PT-141 (Bremelanotide), 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.
PT-141 (Bremelanotide) — origin
PT-141 is a metabolite of Melanotan II, and its history is an unusually direct case of a side effect becoming the research programme. Melanotan II was developed as a synthetic α-MSH analogue for pigmentation research; an unanticipated effect observed during that work redirected attention to the metabolite, which was then developed separately as bremelanotide.
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.
PT-141 (Bremelanotide) research themes
Acts at melanocortin receptors, with MC3R and MC4R the subtypes of research interest.
Distinguished in the literature by acting centrally, unlike vascular-mechanism compounds in adjacent research areas.
Its origin as a metabolite of a pigmentation-research compound is central to understanding its development history.
The lactam bridge restricts conformational freedom, a common strategy for improving receptor selectivity.
SS-31 research themes
Studied for selective association with cardiolipin in the inner mitochondrial membrane, the basis of its mitochondrial targeting.
Examined for effects on mitochondrial energy production in research models of mitochondrial dysfunction.
Investigated around reactive-oxygen-species handling at the mitochondrion.
PT-141 (Bremelanotide) handling
- Protect from light at all stages.
- Standard gentle reconstitution; the constrained ring is not agitation-sensitive in the way flexible long chains are.
- Store refrigerated and aliquot rather than repeatedly sampling one vial.
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 PT-141 (Bremelanotide) 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.
PT-141 (Bremelanotide) reference
Related comparisons
PT-141 (Bremelanotide) 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.