Kisspeptin-10: One Gene, Four Peptides, and Which One This Is

Kisspeptin-10 is the last ten residues of a 54-residue peptide. Its sequence, mass, the names used loosely around it, and how its research began.

Published 28 October 2026

"Kisspeptin" is not one molecule. It is the name of a family of peptides cut from a single precursor protein, and the four members usually named differ in length by more than five times. Kisspeptin-10 is the shortest of them: the last ten residues of the longest. Most of the confusion around this compound comes from reading the family name as if it named one substance, so this page sets out which molecule kisspeptin-10 is, how it relates to its relatives, and what kind of research has actually been done with it.

The molecule#

The sequence, its position and the amidated final phenylalanine are as recorded in UniProt entry Q15726, the curated record for the human KISS1 protein. The formula, weight and CAS number match the R&D Systems reference listing, and we checked the arithmetic from the sequence ourselves.

The "-NH2" at the end is not decoration. The C-terminal amide is part of the natural peptide, and the free-acid version is a different compound with a mass about one dalton higher (1303.4). A mass spectrum separates the two; a hurried reading of one may not.

One gene, four peptides#

The KISS1 gene encodes a precursor protein of 138 residues. Cutting it at different points gives the peptides that the literature names by their length, all recorded in the same UniProt entry:

• Kisspeptin-54 (residues 68–121), the form first isolated, also called metastin
• Kisspeptin-14 (residues 108–121)
• Kisspeptin-13 (residues 109–121)
• Kisspeptin-10 (residues 112–121)

All four end in the same ten residues, finishing Arg-Phe-NH2, which places kisspeptin in the wider RF-amide peptide family. That shared tail is the part that engages the receptor, which is why the shortest form remains active at it in laboratory work. One of the first human studies of kisspeptin-10 describes it as the shortest kisspeptin fragment with full intrinsic bioactivity (George et al., 2011).

Where the names get used loosely#

• "Kisspeptin" on its own. In a paper title this can mean kisspeptin-54, kisspeptin-10, or the whole system. Read the methods: a finding about one length is not automatically a finding about another.
• "Metastin." Strictly this is kisspeptin-54, the name its discoverers gave it. "Metastin (45–54)" is kisspeptin-10, numbered from within the 54-residue peptide.
• KiSS-1, KISS1 and KISS1R. KISS1 is the gene (written KiSS-1 in the 1996 paper that found it). KISS1R is the receptor, which most older papers call GPR54 and one of the 2001 papers called hOT7T175. They are three different things that share a stem.
• Human or rodent. Mouse and rat kisspeptin-10 end in tyrosine rather than phenylalanine: one extra oxygen, about sixteen daltons heavier (1318.4). Our product page sets out the two side by side. Unqualified, "kisspeptin-10" means the human sequence.

How the literature began#

The story starts in cancer biology, not reproduction. In 1996 Danny Welch's group at Penn State reported a gene, which they named KiSS-1, whose expression was associated with non-metastatic melanoma cells, and whose transfer into metastatic melanoma cells reduced metastasis in mouse experiments (Lee et al., 1996, JNCI).

In 2001 several groups independently found what the gene's products do. Ohtaki and colleagues at Takeda isolated an amidated 54-residue peptide from human placenta, showed it was the natural ligand of an orphan receptor, and named it metastin (Ohtaki et al., 2001, Nature). Marc Parmentier's group in Brussels reported the same receptor pairing, named the peptides kisspeptins and characterised the shorter forms (Kotani et al., 2001, J Biol Chem).

The turn towards reproduction came in 2003, when two groups described families with hypogonadotropic hypogonadism, a condition of absent or incomplete puberty, carrying loss-of-function mutations in the receptor gene. One was Nicolas de Roux's group in Paris (de Roux et al., 2003, PNAS). The other was a Boston and Cambridge collaboration that also bred mice lacking the receptor (Seminara et al., 2003, NEJM). Since then kisspeptin signalling has been studied mainly as an upstream regulator of gonadotropin-releasing hormone (GnRH) neurones in the hypothalamus.

What kinds of studies exist#

The kisspeptin literature now runs to thousands of papers. Broadly, it falls into five groups.

Cell and receptor work. Binding and signalling studies in cell lines engineered to express KISS1R, a Gq/11-coupled receptor, and invasion and migration assays from the original oncology strand. Most structure–activity work on the shorter peptides sits here.

Cancer biology. The original strand never went away. Because KISS1 was first identified as a metastasis suppressor, a separate body of work examines KISS1 expression in tumour samples and the effect of kisspeptins on the migration and invasion of cancer cells in culture and in mouse models. It shares a molecule with the reproductive literature but asks entirely different questions, so a search for "kisspeptin" returns two literatures mixed together.

Animal physiology. Studies in rodents, sheep and non-human primates that measure GnRH and luteinising hormone (LH) secretion, map kisspeptin neurones in the hypothalamus, and examine the timing of puberty. Knockout mice from 2003 onwards are a large part of this.

Human physiology studies. These are experimental-medicine studies in small groups of volunteers, generally measuring hormone levels in blood. The first, from Imperial College London, used kisspeptin-54 in six men in a double-blind, placebo-controlled crossover design (Dhillo et al., 2005, JCEM). Kisspeptin-10 was first studied in men in Edinburgh, measuring LH and the frequency of its pulses (George et al., 2011, JCEM). A study the same year compared men and women and reported that hormone responses to kisspeptin-10 differed by sex and, in women, by phase of the menstrual cycle (Jayasena et al., 2011, JCEM). Men showed rises in LH and follicle-stimulating hormone; women studied in the early (follicular) phase showed no change in either, while women studied around the time of ovulation did. The authors called this sexual dimorphism, and it is a reminder that a result in one group of volunteers says little about another.

Clinical research in reproductive medicine. Some groups have moved on to clinical studies, most prominently in IVF. These have mostly used kisspeptin-54 rather than kisspeptin-10: a 2014 study of 53 women undergoing IVF measured egg maturation and later outcomes (Jayasena et al., 2014, J Clin Invest). It is a useful illustration of why the length matters. A newcomer who reads "kisspeptin was studied in IVF" and attaches that to a vial of kisspeptin-10 has merged two different molecules.

Two cautions about this body of work. First, most of the human studies are small, short and designed to describe physiology, not to establish any clinical use. Second, no kisspeptin is a licensed medicine in the United Kingdom. The research history is real and substantial; it is a history of studying a signalling system, not of developing a product.

What to check on a certificate#

Kisspeptin-10 is a good example of a peptide where identity can be checked in one number, and where the number most often goes wrong:

• A mass near 1302: human kisspeptin-10, amidated, as specified.
• A mass near 1318: the rodent sequence, ending in tyrosine.
• A mass near 1303: possibly the free acid rather than the amide. One dalton is resolvable, but read the figure carefully.
• No mass at all: a purity figure alone cannot tell you which of these you have.

A purity percentage says how much of the sample is the main component, not what that component is. Our guides on what an HPLC purity figure means and how to verify a certificate is genuine cover this in more detail, and the post on purity testing versus quantification explains why "how pure" and "how much" are separate questions.

Salt form is the other variable. Kisspeptin-10 is usually made as a trifluoroacetate or acetate salt, and the counter-ion adds weight that the free-base figure does not include. That is why we quote the free-base weight and do not print a salt weight we cannot source. Ask about batch documentation before ordering.

Handling#

Kisspeptin-10 is supplied as a lyophilised powder and needs nothing unusual beyond the general rules for small peptides. The storage temperatures are on the product page. For technique, see how to reconstitute research peptides and how to store research peptides, rather than any instructions repeated here.

What this page does not claim#

Nothing here concerns what kisspeptin-10 does, or might do, in a person or animal outside a laboratory study. The studies above are described as history: who did what kind of work, in which models, measuring what. This page is about which molecule the name refers to, a question with a definite answer. For how UK law applies to material sold this way, see what "research use only" actually means.

In our catalogue#

• Kisspeptin-10: human sequence, C-terminal amide, 1302.4 g/mol free base

Supplied for laboratory research use only. Not for human or veterinary use.

Pioneer Research Peptides — UK supplier of research peptides for laboratory use. Ask about batch documentation before you order.

For laboratory research use only — not for human consumption. 18+.