What is kisspeptin and how to verify its quality
Kisspeptin shows up more and more in research-material catalogs, but few sources explain what the molecule actually is without crossing into clinical claims. Here is what the published research describes about the peptide itself: its chemical identity, the receptor it acts on, and how a batch is verified in the lab. This is research-use-only (RUO) content: it does not cover human use, dosing, protocols or effects.
What kisspeptin is
Kisspeptin is a neuropeptide: a short chain of amino acids that works as a signaling molecule. It is not a single compound but a family of fragments derived from the same precursor, encoded by the KISS1 gene. The longest fragment has 54 amino acids (kisspeptin-54), and shorter versions of 14, 13 and 10 amino acids are cleaved from it, all sharing the same chemical end (an RF-amide terminus). Kisspeptin-10 is the smallest active fragment and the one most often handled in the lab.
That shared origin matters when you verify a vial. "Kisspeptin" can refer to different fragments with different molecular weights, so a vial's Certificate of Analysis has to specify which one it contains.
From metastasis suppressor to neuropeptide
The name has an odd history. The gene was first described in 1996, when a team at Pennsylvania State University, in the town of Hershey, identified it as a metastasis-suppressor gene in human melanoma cells and named it KiSS-1 (see Sources). In that work, introducing human chromosome 6 into melanoma cells reduced their ability to metastasize by more than 95% without affecting their ability to form the original tumor, and the new gene was isolated from those cells.
Five years later, in 2001, another team showed that this gene encodes the peptides that act as the natural ligands of an "orphan" receptor (one whose activator was not yet known) called GPR54. They named those peptides kisspeptins (see Sources). A molecule discovered in a cancer context ended up defining an entire signaling system.
The KISS1R (GPR54) receptor and the hormonal axis
Kisspeptin signals by binding to a receptor called KISS1R, also known by its original name GPR54. The importance of that receptor became clear in 2003. A study published in The New England Journal of Medicine found that people carrying a mutation in the GPR54 gene did not start puberty, and concluded that the receptor is required for the normal function of the hormonal system that controls reproduction (see Sources).
That is why kisspeptin is studied within the endocrinology of the reproductive axis. It is worth flagging the compliance nuance: this finding describes what research observed about the molecule and its receptor. It does not describe an effect of any product or a use indication, and any question about fertility, hormones or application in people falls outside research and is not addressed here.
Kisspeptin: where to buy and how to verify quality
For lab work, the useful question is more concrete: whether the vial really contains what the label says. Two data points answer it. Identity is confirmed by mass spectrometry: the measured molecular weight has to match the theoretical value of the stated fragment (54, 13 or 10 amino acids, depending on the case). Purity is measured by high-performance liquid chromatography (HPLC), which separates the components of the sample and calculates what percentage of the total area corresponds to the main peak.
The two values are read together and per batch. The guide on what HPLC purity is explains where that percentage comes from, and how to read a COA walks through the full document. Anyone looking for where to buy kisspeptin at research grade should always request the COA for the specific batch they will receive, not a generic catalog reference. In Égida's catalog you can buy kisspeptin with a per-batch Certificate of Analysis, and the comparison tool shows it alongside the rest of the molecules.
Reconstitution and handling
Kisspeptin is distributed lyophilized, as a dry powder, because in that state the molecule ships and stores more stably. Before an assay it is reconstituted with an appropriate liquid, and the resulting concentration depends only on the milligrams in the vial and the volume added. The peptide calculator does that conversion, the step-by-step reconstitution guide covers the procedure, and bacteriostatic vs. sterile water explains which liquid applies. To see the molecule next to the full catalog and check the current price, the page on kisspeptin price brings together the batch COA and shipping details, and research peptides groups the whole category.
Sources
- Lee JH, Miele ME, Hicks DJ, et al. KiSS-1, a novel human malignant melanoma metastasis-suppressor gene. J Natl Cancer Inst. 1996;88(23):1731–1737. PubMed 8944003 · doi:10.1093/jnci/88.23.1731
- Kotani M, Detheux M, Vandenbogaerde A, et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54. J Biol Chem. 2001;276(37):34631–34636. PubMed 11457843
- Seminara SB, Messager S, Chatzidaki EE, et al. The GPR54 gene as a regulator of puberty. N Engl J Med. 2003;349(17):1614–1627. PubMed 14573733 · doi:10.1056/NEJMoa035322