By the Peptide.Express Editorial Team
Research area
Quick Answer
The honest answer first: Peptide.Express does not stock a cognitive-endpoint toolkit. Semax is stocked as a research peptide, but this page does not present it — or PT-141 or Kisspeptin-10 — as a cognition compound. Selank and Dihexa are not in this catalogue. What this page lists are two central nervous system receptor tools already in the storefront: PT-141 (hypothalamic MC3R/MC4R) and Kisspeptin-10 (GPR54 on GnRH neurons). Both are neuroendocrine CNS pharmacology. Neither has published memory, attention, or learning-endpoint data that would justify a cognitive-research recommendation.
Research context
This page does not recommend cognition-endpoint peptides. It lists two CNS receptor tools already stocked for neuroendocrine research. Research use only.
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Central nervous system signalling and cognition are not the same subject, and collapsing them is how vendor pages end up recommending a melanocortin agonist for memory. PT-141 is used in hypothalamic circuit work precisely because it has no meaningful activity on vascular smooth muscle — it is the CNS-side reference compound when a PDE5 inhibitor supplies the peripheral arm. Kisspeptin-10 is studied with patch-clamp recording of GnRH neuron firing, which is neuronal electrophysiology in the strict sense and reproductive neuroendocrinology in subject matter. If the endpoint is memory, attention or learning, nothing in this catalogue is the right tool. That is a shorter list than most sites publish against this query, and it is the accurate one.
A cyclic heptapeptide agonist at MC3R and MC4R, both centrally distributed — MC4R densely in the paraventricular nucleus and medial preoptic area, MC3R in the arcuate nucleus and limbic structures. It is the standard tool for separating central from peripheral mechanism, since it does not act on vascular smooth muscle. It has not been studied against cognitive endpoints.
A decapeptide GPR54/KISS1R agonist that couples through Gq rather than Gs, which is unusual among the neuroendocrine compounds here. The research use is GnRH neuron electrophysiology and LH pulse-generator work. GPR54 desensitises under continuous exposure, so bolus and infusion designs can read out in opposite directions on the same endpoint.
The nootropic peptide literature centres on Semax, Selank and Dihexa, with memory, learning and neurotrophic endpoints. Peptide.Express stocks Semax as a research peptide; Selank and Dihexa are not in this catalogue. The compounds listed on this page (PT-141 and Kisspeptin-10) are neuroendocrine CNS tools, not cognition-endpoint agents, and should not be substituted for that literature.
No. Both act in the central nervous system, which is a different claim entirely. PT-141 is a melanocortin agonist studied in hypothalamic circuit and feeding-pathway models; Kisspeptin-10 is a GPR54 agonist studied in the hypothalamic-pituitary-gonadal axis. Neither has published memory, attention or learning data behind it.
None that we can point to a source for. Several compounds cross into the central nervous system — DSIP is used as a reference compound in blood-brain barrier transport research — but crossing the barrier is a pharmacokinetic property, not a cognitive effect. We would rather publish that gap than manufacture a rationale to fill it.
One functional group. Melanotan II ends in a carboxamide, PT-141 in a free acid, and the mass gap is about 1 Da. That single change shifted receptor selectivity enough to send the two molecules down separate paths — PT-141 lost most of the MC1R and MC5R activity Melanotan II retains, which is why the pair is used for selectivity attribution.
Yes. For Kisspeptin-10, the C-terminal amide is the specification to check on the Certificate of Analysis where one is on file; without it, receptor binding at GPR54 falls off sharply. PT-141 and Kisspeptin-10 are sourced against a ≥99% HPLC purity specification.
Explore our complete catalog of research peptides. Same-day US shipping on orders before 2 PM EST. Sourced against a ≥99% HPLC purity specification. Third-party Certificates of Analysis are published where on file. For laboratory research use only. Not for human or veterinary use.
Compiled by the Peptide.Express Editorial Team. Written and reviewed by Peptide.Express Editorial Team. Molecular identity on this page (name, CAS number, molecular formula and molecular weight) is resolved from a single internal entity record and checked against primary registries (PubChem, CAS Common Chemistry) rather than retyped per page. A field with no verified value is left out instead of estimated. Literature is cited to a DOI, PMID or PMCID permalink so every reference resolves to the specific record it names.