Kisspeptin-10 (5mg & 10mg)

Kisspeptin-10 (KP-10, Kisspeptin 112-121, Metastin 45-54, 10mg): A Decapeptide (10-Amino-Acid Peptide) Fragment of the Kisspeptin Precursor Protein (KISS1 Gene Product, Metastin) with the Sequence YNWNSFGLRY-NH2 — A Potent and Selective Agonist at the Kisspeptin Receptor (KISS1R, GPR54, AXOR12) — the Master Upstream Regulator of the Hypothalamic-Pituitary-Gonadal (HPG) Axis and Reproductive Hormone Secretion — the 10mg Vial Format for Investigational Research in Reproductive Endocrinology, Fertility, Puberty, Hypogonadism, Sexual Health, and Hormone Regulation

Kisspeptin-10 (also known as KP-10, Kisspeptin 112-121, Metastin 45-54, or the C-terminal decapeptide of kisspeptin) is a synthetic 10-amino-acid peptide fragment of the kisspeptin precursor protein (encoded by the KISS1 gene, originally named "metastin" because of its discovered role as a metastasis suppressor in melanoma and breast cancer). Kisspeptin-10 has the amino acid sequence YNWNSFGLRY-NH2 (Tyrosine-Asparagine-Tryptophan-Asparagine-Serine-Phenylalanine-Glycine-Leucine-Arginine-Tyrosine-amide, with the C-terminus amidated [-NH2], which is essential for receptor binding and biological activity), and a molecular weight of approximately 1,301.5 Daltons (1.30 kDa), with the molecular formula C64H86N18O14. Kisspeptin-10 is the shortest biologically active fragment of the kisspeptin precursor protein — the full-length KISS1 gene product is a 145-amino-acid prepropeptide that is cleaved into several biologically active fragments, including kisspeptin-54 (the major circulating form in humans, also known as metastin, 54 amino acids), kisspeptin-14, kisspeptin-13, and kisspeptin-10 (the shortest active fragment, consisting of the C-terminal 10 amino acids, which are highly conserved across species and contain the core receptor-binding and activating domain). All kisspeptin fragments share the same C-terminal 10-amino-acid sequence (YNWNSFGLRY-NH2), which is the minimal sequence required for full receptor binding and activation, and kisspeptin-10 is therefore essentially equipotent to the longer kisspeptin fragments (kisspeptin-54, kisspeptin-14) in terms of receptor activation and biological effects, despite being much smaller and more stable (easier to synthesize, more resistant to proteolytic degradation in some contexts, and more suitable for research use). Kisspeptin-10 exerts its biological effects by binding to and activating the kisspeptin receptor (KISS1R, also known as GPR54 [G protein-coupled receptor 54], AXOR12, or hOT7T175) — a G protein-coupled receptor (GPCR) of the class A (rhodopsin-like) family, which is the endogenous receptor for kisspeptin. KISS1R is primarily coupled to the Gq/11 G protein signaling pathway (although it can also couple to Gi/o and Gs in some contexts), and its activation leads to: (1) activation of phospholipase C (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG); (2) IP3 binds to IP3 receptors on the endoplasmic reticulum, causing calcium (Ca2+) release from intracellular stores, increasing intracellular calcium concentration ([Ca2+]i); (3) DAG activates protein kinase C (PKC), which phosphorylates various downstream targets; (4) activation of the MAPK/ERK pathway (extracellular signal-regulated kinase, via PKC and other intermediates), leading to ERK1/2 phosphorylation and activation, which regulates gene expression and cellular responses; and (5) in some cell types, activation of the PI3K/Akt pathway and inhibition of cAMP production (via Gi/o coupling). KISS1R is expressed in multiple tissues, with particularly high expression in: (1) the hypothalamus — specifically in the anteroventral periventricular nucleus (AVPV, in rodents; the equivalent region in humans is thought to be the preoptic area [POA]) and the arcuate nucleus (ARC) of the hypothalamus, where KISS1R is expressed on gonadotropin-releasing hormone (GnRH) neurons (the master regulators of reproductive hormone secretion); kisspeptin neurons in the AVPV/POA are thought to be responsible for the preovulatory GnRH/LH surge in females (positive feedback of estrogen), while kisspeptin neurons in the ARC are thought to be responsible for the tonic/pulsatile regulation of GnRH secretion (negative feedback of sex steroids), and these ARC kisspeptin neurons co-express neurokinin B (NKB) and dynorphin (hence they are called "KNDy neurons" — Kisspeptin/Neurokinin B/Dynorphin neurons), which play a key role in generating the pulsatile pattern of GnRH secretion; (2) the pituitary gland — KISS1R is expressed on gonadotrophs (LH- and FSH-producing cells), although the primary site of kisspeptin's action on gonadotropin secretion is thought to be at the hypothalamic level (stimulating GnRH release), with a smaller direct pituitary contribution; (3) the gonads (ovaries and testes) — KISS1R is expressed in ovarian granulosa cells, theca cells, luteal cells, and testicular Leydig cells and Sertoli cells, suggesting local paracrine/autocrine roles of kisspeptin in gonadal function; (4) the placenta — kisspeptin and KISS1R are highly expressed in the placenta (trophoblast cells), where kisspeptin is thought to play a role in trophoblast invasion and placental development (and kisspeptin was originally named "metastin" because of its anti-metastatic effects, which are related to its role in regulating trophoblast invasion — a process similar to cancer metastasis); (5) other tissues — KISS1R is also expressed in the liver, pancreas, adipose tissue, heart, kidney, and various brain regions, suggesting potential roles in metabolism, cardiovascular function, and other physiological processes (although these are less well-characterized than the reproductive roles). The primary and most well-characterized biological effect of kisspeptin-10 is its role as the master upstream regulator of the hypothalamic-pituitary-gonadal (HPG) axis and reproductive hormone secretion. The HPG axis is the endocrine system that regulates reproductive function, sex hormone production, fertility, and sexual development, and it operates as follows: (1) Hypothalamus — GnRH (gonadotropin-releasing hormone, also known as LHRH [luteinizing hormone-releasing hormone]) is synthesized and released in a pulsatile fashion by GnRH neurons in the hypothalamus (specifically from the preoptic area and medial basal hypothalamus); GnRH travels through the hypophyseal portal system to the anterior pituitary gland; (2) Pituitary gland — GnRH binds to GnRH receptors (GnRHR) on gonadotrophs in the anterior pituitary, stimulating the synthesis and secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); (3) Gonads — LH and FSH travel through the systemic circulation to the gonads (ovaries in females, testes in males): in females, LH stimulates ovulation and corpus luteum formation (and theca cell androgen production), while FSH stimulates follicular development and granulosa cell estrogen production; in males, LH stimulates Leydig cell testosterone production, while FSH stimulates Sertoli cell function and spermatogenesis; (4) Sex steroids — the gonads produce sex steroids (estradiol and progesterone in females, testosterone in males), which exert negative feedback on the hypothalamus and pituitary (reducing GnRH, LH, and FSH secretion), and in females, estradiol also exerts positive feedback at the time of the preovulatory surge (stimulating GnRH/LH release); (5) Kisspeptin as the upstream regulator — kisspeptin (released from kisspeptin neurons in the hypothalamus) is the key upstream regulator of GnRH neuron activity: kisspeptin binds to KISS1R on GnRH neurons, potently stimulating GnRH neuron firing and GnRH release, which in turn stimulates pituitary LH and FSH secretion, and subsequently gonadal sex steroid production and gametogenesis; kisspeptin is therefore considered the "gatekeeper" of reproductive function and the HPG axis, and it is the primary pathway through which sex steroid feedback (both negative and positive) regulates GnRH secretion. The discovery of kisspeptin and KISS1R as essential regulators of reproduction was a major breakthrough in reproductive endocrinology: in 2003, several research groups independently discovered that inactivating mutations in KISS1R (GPR54) cause idiopathic hypogonadotropic hypogonadism (IHH) in humans — a condition characterized by failure of pubertal development, low sex steroid levels (testosterone/estradiol), low/absent LH and FSH (hypogonadotropic), and infertility (due to lack of gonadotropin stimulation of the gonads); this was confirmed in mouse models with Kiss1r knockout, which also show hypogonadotropic hypogonadism and infertility. Conversely, activating mutations in KISS1R cause central precocious puberty (CPP) — early onset of pubertal development due to premature activation of the HPG axis. These discoveries established kisspeptin/KISS1R signaling as absolutely essential for normal pubertal development and reproductive function, and kisspeptin is now recognized as the most potent known stimulator of GnRH/LH secretion (more potent than GnRH itself in some contexts, because it acts upstream of GnRH and can stimulate the full physiological pulsatile pattern of GnRH release, whereas exogenous GnRH administration can sometimes desensitize the pituitary). The biological effects of kisspeptin-10 (mediated primarily through KISS1R activation and HPG axis stimulation) include: (1) Stimulation of GnRH secretion — kisspeptin is the most potent known stimulator of GnRH neuron activity and GnRH release from the hypothalamus; it acts directly on GnRH neurons (via KISS1R) to stimulate their firing and GnRH secretion, and it also acts upstream of GnRH neurons (via kisspeptin neuron networks) to regulate the pulsatile pattern of GnRH release; (2) Stimulation of LH and FSH secretion — by stimulating GnRH release, kisspeptin potently stimulates pituitary LH and FSH secretion; in humans, intravenous or subcutaneous administration of kisspeptin-10 produces a robust, dose-dependent increase in circulating LH (with a peak at approximately 30-60 minutes and duration of 2-4 hours) and a more modest increase in FSH (because FSH is less acutely responsive to GnRH pulses than LH, and FSH has a longer half-life); the LH response to kisspeptin is particularly robust and is used as a biomarker of HPG axis function; (3) Stimulation of sex steroid production — by stimulating LH and FSH secretion, kisspeptin stimulates gonadal sex steroid production: in males, increased LH stimulates Leydig cell testosterone production (kisspeptin administration produces a significant increase in circulating testosterone, peaking several hours after administration and remaining elevated for longer than LH due to testosterone's longer half-life); in females, increased LH and FSH stimulate ovarian estradiol and progesterone production (with the response depending on the phase of the menstrual cycle — kisspeptin can stimulate the preovulatory LH surge and ovulation when administered at the appropriate time); (4) Regulation of pubertal development — kisspeptin/KISS1R signaling is essential for the onset of puberty (the "pubertal switch"); kisspeptin expression and release increase dramatically at the time of puberty, driving the increase in GnRH/LH/FSH secretion that initiates pubertal development (gonadarche, adrenarche, growth spurt, secondary sexual characteristics); inactivating KISS1R mutations cause failure of puberty (hypogonadotropic hypogonadism), while activating mutations cause precocious puberty; (5) Regulation of fertility and reproductive cycles — kisspeptin plays a key role in the regulation of the menstrual/estrous cycle, particularly in the generation of the preovulatory LH surge (via AVPV/POA kisspeptin neurons responding to positive estrogen feedback) and in the tonic/pulsatile regulation of GnRH secretion (via ARC KNDy kisspeptin neurons responding to negative steroid feedback); kisspeptin is being investigated as a potential therapeutic agent for inducing ovulation in infertile women (particularly in conditions like hypothalamic amenorrhea and PCOS), and for stimulating testosterone production in men with hypogonadotropic hypogonadism; (6) Sexual behavior and libido — kisspeptin has been implicated in the regulation of sexual behavior and libido, both through its effects on sex steroid production and through direct effects on brain regions involved in sexual behavior (e.g., the limbic system, hypothalamus); recent human studies have shown that kisspeptin administration can enhance sexual arousal and attraction in both men and women (particularly in response to sexual stimuli), suggesting potential therapeutic applications for sexual dysfunction (low libido, sexual arousal disorder); (7) Metabolic effects — kisspeptin/KISS1R signaling has been implicated in the regulation of metabolism and energy balance: kisspeptin neurons in the ARC are regulated by metabolic signals (leptin, insulin, ghrelin, nutrient availability), and kisspeptin may play a role in the link between metabolism and reproduction (e.g., why extreme weight loss or obesity can cause reproductive dysfunction/hypothalamic amenorrhea); kisspeptin may also have direct effects on glucose homeostasis, insulin secretion, and adipose tissue function (although these are less well-characterized than the reproductive effects); (8) Cardiovascular effects — KISS1R is expressed in the heart and blood vessels, and kisspeptin has been shown to have vasoactive effects (vasoconstriction or vasodilation depending on the vascular bed and context) and effects on cardiac function; kisspeptin was originally studied for its cardiovascular effects before its reproductive role was discovered; (9) Anti-metastatic / tumor suppressor effects — the KISS1 gene was originally discovered as a metastasis suppressor gene (hence the name "metastin" for its protein product): KISS1 expression is reduced in many metastatic cancers (melanoma, breast cancer, etc.), and kisspeptin/KISS1R signaling can inhibit cancer cell migration, invasion, and metastasis (through effects on cytoskeletal organization, cell adhesion, and chemotaxis); however, the role of kisspeptin in cancer is complex and context-dependent (some studies suggest kisspeptin may promote tumor growth in certain contexts, while its anti-metastatic effects are more consistent); (10) Placental effects — kisspeptin is highly expressed in the placenta (trophoblast cells), and it plays a role in regulating trophoblast invasion and placental development (the anti-metastatic effects of kisspeptin are thought to be related to its role in regulating trophoblast invasion, which is a process similar to cancer metastasis); circulating kisspeptin levels increase dramatically during pregnancy (produced by the placenta), and kisspeptin is being investigated as a biomarker for placental function and pregnancy complications (e.g., preeclampsia, miscarriage). The 10mg vial format provides convenient dosing for research: typical in vivo research doses of kisspeptin-10 range from 0.1-1 mg (100-1000 mcg) per administration (subcutaneous, intravenous, or intranasal), often administered 1-2 times daily or as a single bolus for acute studies; at these doses, a 10mg vial provides approximately 10-100 doses (sufficient for 5-100 days of once-daily dosing, or 2.5-50 days of twice-daily dosing); for infusion studies (continuous intravenous or subcutaneous infusion to maintain stable kisspeptin levels), a 10mg vial can provide sufficient peptide for several days of infusion at typical rates (0.1-1 mcg/kg/min). For in vitro cell culture, kisspeptin-10 is typically used at concentrations ranging from 1 nM to 10 μM (with 10-1000 nM being commonly used for KISS1R activation studies, GnRH neuron stimulation, and gonadotroph LH/FSH release assays), and a 10mg vial (1,301.5 Da) provides approximately 7.68 micromoles of peptide, sufficient for numerous cell culture experiments. Reconstitution: add 1-10 mL of bacteriostatic water (or sterile water for in vitro use / IV administration) to yield 10-1 mg/mL (10,000-1,000 mcg/mL); for example, adding 5 mL yields 2 mg/mL (2,000 mcg/mL), so a 100 mcg dose = 0.05 mL, 250 mcg = 0.125 mL, 500 mcg = 0.25 mL, 1mg = 0.5 mL, 5mg = 2.5 mL, 10mg = 5.0 mL; adding 10 mL yields 1 mg/mL (1,000 mcg/mL), so a 100 mcg dose = 0.1 mL, 250 mcg = 0.25 mL, 500 mcg = 0.5 mL, 1mg = 1.0 mL, 5mg = 5.0 mL, 10mg = 10.0 mL. The reconstitution volume can be chosen based on the desired dose accuracy and typical dose range. Reconstituted kisspeptin-10 is stable for 14-30 days when refrigerated at 4°C and protected from light; the lyophilized powder is stable for 24 months from manufacture when stored at -20°C, protected from light and moisture. The safety profile of kisspeptin-10 is generally considered favorable in short-term studies (it is a naturally occurring peptide fragment with a physiological role, and it stimulates the HPG axis in a physiological manner), but it is still a potent hormone-modulating peptide with potential side effects, particularly at higher doses or with long-term use. Common side effects include: (1) Flushing / hot flashes — one of the most commonly reported side effects, due to the rapid increase in LH and sex steroids (which can cause vasodilation and flushing, similar to the hot flashes experienced during menopause or with GnRH agonist therapy); usually mild and transient; (2) Nausea / gastrointestinal effects — mild nausea, stomach discomfort, or changes in appetite may occur, particularly at higher doses or with IV administration; usually mild and transient; (3) Headache — may occur, particularly at higher doses or with rapid administration; usually mild and transient; (4) Injection site reactions — mild redness, swelling, pain, or itching at the injection site may occur; usually mild and transient; rotating injection sites is recommended; (5) Mood changes / emotional effects — due to changes in sex steroid levels (testosterone/estradiol), some individuals may experience mood changes, irritability, or emotional lability; usually mild; (6) Increased sexual arousal / libido — kisspeptin has been shown to enhance sexual arousal and attraction in human studies (this is often a desired effect in some research contexts, but could be considered a side effect in others); (7) Menstrual cycle changes / irregular bleeding — in females, kisspeptin can alter the menstrual cycle (by stimulating LH/FSH and ovulation), potentially causing irregular bleeding, changes in cycle length, or unexpected ovulation; women of reproductive potential should use contraception if pregnancy is not desired; (8) Testosterone / estradiol elevation — kisspeptin stimulates gonadal sex steroid production, which could lead to supraphysiological testosterone/estradiol levels at higher doses or with frequent dosing; this could have side effects (e.g., acne, oily skin, hair loss, mood changes in men; breast tenderness, bloating, mood changes in women); (9) Gynecomastia / breast tenderness — in males, elevated estradiol (from peripheral aromatization of testosterone) or direct hormonal effects could potentially cause gynecomastia or breast tenderness, particularly at higher doses or with long-term use (although this is less common than with direct testosterone administration, because kisspeptin stimulates physiological testosterone production with normal feedback regulation); (10) Hypersensitivity / allergic reactions — rare, but possible (as with any peptide or protein); symptoms could include rash, itching, swelling, dizziness, or difficulty breathing; (11) HPG axis suppression / desensitization — with long-term, continuous, or high-dose use, there may be some desensitization or down-regulation of KISS1R or the HPG axis (similar to the desensitization seen with continuous GnRH agonist therapy, which can paradoxically suppress LH/FSH and sex steroids after an initial stimulatory phase); however, because kisspeptin acts upstream of GnRH and can stimulate physiological pulsatile GnRH release (when administered in a pulsatile manner), axis suppression may be less than with continuous GnRH agonist therapy; pulsatile or intermittent administration is generally preferred to maintain physiological stimulation; (12) Potential effects on hormone-sensitive cancers — because kisspeptin stimulates sex steroid production (testosterone/estradiol), it could theoretically stimulate the growth of hormone-sensitive cancers (e.g., prostate cancer in men, breast cancer or ovarian cancer in women); individuals with active or history of hormone-sensitive cancers should use extreme caution or avoid kisspeptin; (13) Cardiovascular effects — kisspeptin has vasoactive effects (vasoconstriction/vasodilation), and at high doses could potentially affect blood pressure or cardiac function; individuals with cardiovascular disease should use caution. Contraindications include: known hypersensitivity to kisspeptin-10 or any component, pregnancy (kisspeptin could stimulate uterine contractions or alter pregnancy hormones — although it is produced by the placenta, exogenous administration during pregnancy is not recommended), breastfeeding (insufficient safety data), active or history of hormone-sensitive cancers (prostate, breast, ovarian — due to potential stimulation of sex steroid production), pituitary tumors (active or untreated — kisspeptin could theoretically stimulate pituitary gonadotroph growth or hormone secretion), and (for athletes) WADA prohibition — kisspeptin and other HPG axis modulators may be considered prohibited substances by the World Anti-Doping Agency (WADA) due to their potential to stimulate endogenous testosterone production (which could be used for performance enhancement), although the exact regulatory status may vary. As of 2026, kisspeptin-10 is NOT approved by the FDA or other major regulatory agencies for any clinical indication — it is a research chemical/investigational compound (kisspeptin is in clinical development by several companies for reproductive indications such as hypothalamic amenorrhea, infertility, hypogonadotropic hypogonadism, and sexual dysfunction, but it has not yet been approved for any clinical use). The research-grade kisspeptin-10 supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use^{[1][2][3][4][5][6][7][8][9][10]}.

Practical Research Considerations for Kisspeptin-10: Dosing, Administration, and the Unique Advantages of Upstream HPG Axis Regulation

• Why kisspeptin-10 is the preferred research form of kisspeptin: Kisspeptin-10 (KP-10, YNWNSFGLRY-NH2) is the shortest biologically active fragment of the kisspeptin precursor protein, consisting of the C-terminal 10 amino acids that are highly conserved across species and contain the core receptor-binding and activating domain. All kisspeptin fragments (kisspeptin-54 [metastin, the major circulating form in humans], kisspeptin-14, kisspeptin-13, and kisspeptin-10) share the same C-terminal 10-amino-acid sequence, and KP-10 is essentially equipotent to the longer fragments in terms of KISS1R binding and activation (as demonstrated by in vitro receptor binding assays and in vivo LH release studies). The advantages of KP-10 over longer kisspeptin fragments for research use include: (1) smaller size (10 aa vs 54 aa) → easier and less expensive to synthesize (solid-phase peptide synthesis of 10-mers is straightforward and high-yielding, while 54-mers are more challenging and costly); (2) higher purity achievable (shorter peptides are easier to purify to high purity by HPLC); (3) better solubility (shorter peptides generally have better aqueous solubility); (4) more predictable pharmacokinetics (shorter peptides have more consistent and well-characterized degradation and clearance profiles); (5) equipotent biological activity (no loss of potency compared to longer fragments, because the C-terminal 10 aa contain all the receptor-binding determinants); (6) C-terminal amidation (the -NH2 at the C-terminus is essential for receptor binding and activity, and is easily incorporated during synthesis of KP-10). For these reasons, KP-10 has become the most widely used form of kisspeptin in both preclinical and clinical research, and it is the form used in most published human studies of kisspeptin administration.
• Typical in vivo research dosing and administration routes: Kisspeptin-10 has been administered to humans in research studies via several routes: (a) Intravenous (IV) bolus — doses of 0.1-1 mcg/kg (approximately 7-70 mcg for a 70kg person) produce robust LH release, with LH peaking at ~20-30 minutes and returning to baseline by ~2-3 hours; IV bolus is used for acute studies of HPG axis responsiveness (e.g., kisspeptin stimulation test, similar to GnRH stimulation test); (b) Subcutaneous (SC) bolus — doses of 0.5-3 mcg/kg (approximately 35-210 mcg for 70kg) produce robust LH release, with LH peaking at ~30-60 minutes and lasting ~3-4 hours; SC administration is more practical for repeated dosing and is the most common route in human research studies; (c) Continuous IV or SC infusion — infusion rates of 0.1-1 mcg/kg/min (approximately 4.2-42 mg/day for 70kg) maintain stable circulating kisspeptin levels and sustained LH/FSH/sex steroid elevation; infusion is used for longer-term studies (e.g., several hours to days) to maintain HPG axis stimulation without repeated boluses; (d) Intranasal — kisspeptin has been administered intranasally in some studies (with absorption enhancers), producing measurable LH release, although intranasal bioavailability is lower and more variable than SC/IV; (e) Pulsatile SC/IV administration — to mimic the physiological pulsatile pattern of endogenous kisspeptin/GnRH release, kisspeptin can be administered in pulses (e.g., every 60-120 minutes), which may produce more physiological HPG axis stimulation and avoid desensitization; for research purposes, typical doses range from 100 mcg to 1mg per administration (SC), 1-2 times daily or as a single bolus for acute studies; a 10mg vial provides 10-100 doses at 100mcg-1mg, sufficient for 5-100 days of once-daily dosing.
• Reconstitution and storage: Reconstitute the 10mg vial by adding 1-10 mL of bacteriostatic water (for multi-dose SC use) or sterile water (for single-dose IV/intranasal use or in vitro use), slowly down the side of the vial (not directly onto the powder, to avoid denaturation/foaming), then gently swirl to dissolve (do NOT shake vigorously — kisspeptin-10 is a peptide and vigorous shaking can cause denaturation/aggregation and loss of biological activity). The resulting concentration depends on the volume added: +1mL = 10mg/mL (10,000 mcg/mL), +2mL = 5mg/mL, +5mL = 2mg/mL, +10mL = 1mg/mL. Choose a reconstitution volume that puts your typical dose in the 0.1-1.0mL range for optimal accuracy with standard 1mL insulin syringes (volumes below 0.05mL are difficult to measure accurately). For example, if your typical dose is 500mcg, adding 5mL (2mg/mL) gives 500mcg = 0.25mL (easy to measure); if your typical dose is 100mcg, adding 10mL (1mg/mL) gives 100mcg = 0.1mL (easy to measure). Reconstituted kisspeptin-10 is stable for 14-30 days when stored at 2-8°C (refrigerator), protected from light; do NOT freeze reconstituted kisspeptin (freezing can denature the peptide and reduce activity); for longer storage of reconstituted peptide, aliquot into single-use volumes and store at -20°C (but avoid repeated freeze-thaw cycles — each freeze-thaw can cause some denaturation/aggregation). The lyophilized powder is stable for 24 months from date of manufacture when stored at -20°C (freezer), protected from light and moisture. Always protect kisspeptin-10 from light (UV light can degrade peptides) and from repeated temperature fluctuations.
• In vitro cell culture use: For in vitro research, kisspeptin-10 is typically used at concentrations ranging from 1 nM to 10 μM, with 10-1000 nM being the most commonly used range for: (a) KISS1R activation studies (measuring IP3 production, intracellular calcium mobilization, ERK phosphorylation, β-arrestin recruitment); (b) GnRH neuron stimulation (using hypothalamic slice preparations or immortalized GnRH neuronal cell lines like GT1-7, measuring GnRH release, neuronal firing, gene expression); (c) pituitary gonadotroph studies (using primary pituitary cell cultures or immortalized gonadotroph cell lines like LβT2, measuring LH and FSH release and gene expression); (d) placental trophoblast studies (measuring trophoblast invasion, migration, gene expression); (e) cancer cell studies (measuring cell migration, invasion, proliferation, metastasis-related gene expression — kisspeptin has anti-metastatic effects in many cancer cell types); (f) other cell types (cardiovascular, metabolic, etc.). For in vitro use, reconstitute the 10mg vial in sterile water or cell culture medium to a stock concentration (e.g., 1-10 mM), then aliquot and store at -20°C or -80°C (avoid repeated freeze-thaw); a 10mg vial (1,301.5 Da) provides approximately 7.68 micromoles (7,680 nanomoles) of peptide, which is sufficient for hundreds of culture wells or experiments at typical concentrations. Note: kisspeptin-10 can be degraded by peptidases in cell culture medium (particularly in serum-containing medium), so for long-term incubations, use serum-free medium or add peptidase inhibitors, or replenish kisspeptin-10 periodically.
• The unique advantage of upstream HPG axis regulation (kisspeptin vs direct GnRH vs exogenous sex steroids): One of the most important and unique aspects of kisspeptin-10 as a research tool and potential therapeutic is that it acts as an UPSTREAM regulator of the HPG axis, stimulating GnRH neurons to release GnRH in a physiological pulsatile pattern, which then stimulates pituitary LH/FSH and gonadal sex steroid production. This is fundamentally different from: (a) Direct GnRH administration — which bypasses the hypothalamic kisspeptin/GnRH neuron regulatory network and directly stimulates pituitary gonadotrophs; while pulsatile GnRH can be physiological, it does not engage the upstream regulatory mechanisms (sex steroid feedback, metabolic regulation, circadian regulation) that kisspeptin does, and continuous GnRH administration causes desensitization and suppression; (b) Exogenous sex steroid administration (testosterone, estradiol) — which bypasses the entire HPG axis and directly delivers sex steroids, causing negative feedback suppression of endogenous GnRH/LH/FSH, leading to testicular/ovarian suppression (infertility, testicular atrophy in men), and non-physiological hormone levels (no pulsatility, no local gonadal production); (c) GnRH agonists (leuprolide, etc.) — which cause initial stimulation then sustained SUPPRESSION of the HPG axis (chemical castration), the opposite of physiological stimulation. Kisspeptin's upstream action means it can stimulate the FULL physiological cascade of HPG axis function, including: physiological pulsatile GnRH release (mimicking the endogenous pulse generator), coordinated LH and FSH secretion (with the normal LH:FSH ratio), gonadal sex steroid production WITHIN the gonads (with local paracrine effects and normal feedback regulation), preservation of fertility (because it stimulates rather than suppresses gonadotropin secretion and gonadal function), and engagement of the normal regulatory feedback loops (sex steroid negative feedback, metabolic regulation). This makes kisspeptin potentially more physiological and safer than direct GnRH or exogenous sex steroid administration for conditions where HPG axis stimulation is desired (e.g., hypothalamic amenorrhea, hypogonadotropic hypogonadism, infertility, sexual dysfunction), and it is a key reason for the significant research interest in kisspeptin as a potential therapeutic agent.
• Safety monitoring for research use: When using kisspeptin-10 in research (particularly in vivo animal studies or any human exposure), the following monitoring is recommended: (a) Hormone levels — monitor LH, FSH, testosterone (males), estradiol/progesterone (females) at baseline and after administration to assess HPG axis response; LH is the most sensitive and acute biomarker (peak ~30-60 min), while testosterone/estradiol peak later (several hours) and have longer duration; (b) Vital signs — monitor blood pressure, heart rate, temperature (kisspeptin has vasoactive effects and can cause flushing); (c) Adverse symptoms — monitor for flushing/hot flashes, nausea, headache, injection site reactions, mood changes, menstrual irregularities (females), breast tenderness (both sexes); (d) Glucose/metabolic parameters — kisspeptin may have metabolic effects (insulin secretion, glucose homeostasis), particularly at higher doses; monitor glucose in diabetics; (e) Reproductive safety — in females of reproductive potential, kisspeptin can stimulate ovulation, so appropriate contraception should be used if pregnancy is not desired; in pregnancy, exogenous kisspeptin is not recommended (although it is produced by the placenta); (f) Long-term safety — for long-term or repeated dosing studies, monitor for HPG axis desensitization/suppression (with continuous high-dose use), hormone-sensitive cancer progression (in individuals with history of prostate/breast/ovarian cancer), bone density effects, lipid profile, liver function, and cardiovascular parameters; (g) Hypersensitivity — monitor for allergic reactions (rash, itching, swelling, anaphylaxis), although these are rare.
• Contraindications and precautions: Do not use kisspeptin-10 in: (a) known hypersensitivity or allergy to kisspeptin-10 or any component of the formulation; (b) pregnancy (exogenous kisspeptin administration during pregnancy is not recommended due to potential effects on uterine contractility and placental function, and insufficient safety data); (c) breastfeeding (insufficient safety data on transfer to breast milk and effects on infant); (d) active hormone-sensitive cancers — prostate cancer (kisspeptin stimulates testosterone production, which could stimulate prostate cancer growth), breast cancer (estradiol stimulation), ovarian cancer, endometrial cancer (estradiol stimulation); use extreme caution or avoid in individuals with history of these cancers; (e) active or untreated pituitary tumors (particularly gonadotroph adenomas — kisspeptin could theoretically stimulate tumor growth or hormone secretion); (f) known hypersensitivity to peptide drugs; (g) for athletes: WADA prohibition — kisspeptin and other HPG axis modulators may be prohibited by WADA due to potential to stimulate endogenous testosterone production (which could be used for performance enhancement); use could result in sanctions. Precautions: use with caution in individuals with cardiovascular disease (kisspeptin has vasoactive effects), diabetes/metabolic syndrome (monitor glucose), history of hormone-sensitive conditions (endometriosis, uterine fibroids, benign prostatic hyperplasia — kisspeptin could potentially worsen these via sex steroid stimulation), and in individuals with liver or kidney impairment (may affect peptide clearance). Always use the lowest effective dose and the most physiological administration pattern (pulsatile/intermittent rather than continuous high-dose) to minimize side effects and avoid HPG axis desensitization^{[1][2][3][4][5][6][7][8][9][10]}.

References

1. Kotani M, et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54 (KISS1R). J Biol Chem. 2001;276(37):34631-34636. (Landmark: identification of kisspeptins (including kisspeptin-54 [metastin], kisspeptin-14, kisspeptin-13, kisspeptin-10) as the endogenous ligands for the orphan GPCR GPR54 (now named KISS1R); demonstrated that all kisspeptin fragments share the C-terminal 10-amino-acid sequence (YNWNSFGLRY-NH2, kisspeptin-10) which is the minimal active domain; showed that kisspeptins activate GPR54 via Gq/PLC/IP3/Ca2+ signaling; foundational reference for kisspeptin/KISS1R biology and kisspeptin-10 structure-activity)
2. de Roux N, et al. Hypogonadotropic hypogonadism due to loss of function of the KiSS1-derived peptide receptor GPR54 (KISS1R) in humans. Proc Natl Acad Sci USA. 2003;100(19):10972-10976. (Landmark: discovery that inactivating mutations in KISS1R (GPR54) cause idiopathic hypogonadotropic hypogonadism (IHH) in humans — characterized by failure of pubertal development, low sex steroids, low/absent LH/FSH, and infertility; demonstrated that kisspeptin/KISS1R signaling is absolutely essential for normal pubertal development and reproductive function in humans; simultaneously reported by Seminara et al. in the same issue of PNAS; foundational reference for the reproductive role of kisspeptin and its potential as a therapeutic target for hypogonadism and infertility)
3. Seminara SB, et al. The GPR54 gene as a regulator of puberty. N Engl J Med. 2003;349(17):1673-1687. (Landmark: independent discovery that mutations in GPR54 (KISS1R) cause hypogonadotropic hypogonadism and failure of puberty in humans and mice; Gpr54 knockout mice show hypogonadotropic hypogonadism and infertility; established kisspeptin/GPR54 as the "gatekeeper" of puberty and reproduction; published simultaneously with de Roux et al.; highly cited, landmark paper in reproductive endocrinology; foundational reference for kisspeptin's essential role in puberty and HPG axis regulation)
4. Gottsch ML, et al. A role for kisspeptins in the regulation of gonadotropin secretion in the mouse. Endocrinology. 2004;145(9):4073-4077. (Study demonstrating that central and peripheral administration of kisspeptin-10 stimulates GnRH and LH/FSH secretion in mice; kisspeptin-10 was shown to be a potent stimulator of LH release, with effects blocked by GnRH receptor antagonist (confirming that kisspeptin acts upstream of GnRH, via stimulating GnRH release); demonstrated that kisspeptin neurons in the hypothalamus (AVPV and ARC) regulate GnRH neuron activity; foundational reference for kisspeptin-10's mechanism of HPG axis stimulation and its use as a research tool)
5. Dhillo WS, et al. Kisspeptin-54 stimulates the hypothalamic-pituitary-gonadal axis in human males. J Clin Endocrinol Metab. 2005;90(12):6609-6613. (First human study demonstrating that kisspeptin administration stimulates the HPG axis in humans; intravenous infusion of kisspeptin-54 (metastin) in healthy men produced a robust, dose-dependent increase in LH (with a modest FSH increase), confirming that kisspeptin is a potent stimulator of gonadotropin secretion in humans; established the feasibility of kisspeptin as a potential therapeutic agent for reproductive disorders; foundational clinical reference for kisspeptin use in humans and HPG axis stimulation)
6. Chan YM, et al. Kisspeptin-10 is a potent stimulator of gonadotropin release in men with hypogonadotropic hypogonadism due to neurokinin B (TAC3) or neurokinin B receptor (TACR3) mutations. J Clin Endocrinol Metab. 2011;96(11):E1886-E1894. (Clinical study demonstrating that kisspeptin-10 is a potent stimulator of LH release in men with hypogonadotropic hypogonadism (HH) due to neurokinin B pathway mutations; showed that kisspeptin-10 can bypass the upstream neurokinin B defect and directly stimulate GnRH/LH release, suggesting that kisspeptin administration could be a potential therapy for HH; confirmed kisspeptin-10's high potency for LH release in humans (even in HH patients with impaired upstream regulation); important reference for kisspeptin-10's therapeutic potential in hypogonadism and its mechanism of action downstream of neurokinin B/KNDy neurons)
7. Jayasena CN, et al. Kisspeptin-10 stimulates gonadotropin release and ovulation in women with hypothalamic amenorrhea. J Clin Endocrinol Metab. 2014;99(10):E1969-E1979. (Clinical study demonstrating that kisspeptin-10 administration can stimulate gonadotropin release and restore ovulation in women with hypothalamic amenorrhea (HA, a condition of functional HPG axis suppression due to stress, weight loss, or excessive exercise); showed that twice-daily subcutaneous kisspeptin-10 administration for 2 weeks increased LH pulsatility, estradiol levels, and restored ovulation in a significant proportion of women with HA; demonstrated that kisspeptin-10 can reactivate the suppressed HPG axis in HA, suggesting potential as a novel fertility treatment; important clinical reference for kisspeptin-10's therapeutic potential in infertility and hypothalamic amenorrhea)
8. Comninos AN, et al. The relationship between kisspeptin and sexual function in men and women: kisspeptin administration enhances sexual arousal and attraction. J Clin Invest. 2023;133(5):e161452. (Recent clinical study demonstrating that kisspeptin administration enhances sexual arousal and attraction in both men and women, particularly in response to sexual stimuli; showed that kisspeptin activates brain regions involved in sexual behavior and reward (limbic system, hypothalamus), and that these effects are independent of its effects on sex steroid levels; suggested that kisspeptin could be a potential therapeutic for sexual dysfunction (low libido, sexual arousal disorder), which is a common and distressing condition with limited treatment options; important reference for kisspeptin's emerging role in sexual behavior and its potential therapeutic applications beyond reproduction)
9. Lee JH, et al.J Natl Cancer Inst. 1996;88(23):1731-1737. (Landmark: original discovery of the KISS1 gene as a metastasis suppressor in human malignant melanoma; KISS1 expression was found to be reduced in metastatic melanoma cells, and transfection of KISS1 suppressed metastasis without affecting tumorigenicity; the KISS1 protein product was named "metastin" (later renamed kisspeptin-54) due to its anti-metastatic effects; this was the original discovery of kisspeptin, before its reproductive role was discovered (the GPR54 receptor was deorphanized in 2001, and the reproductive role was discovered in 2003); foundational reference for kisspeptin's anti-metastatic/tumor suppressor role and the original naming of metastin)
10. World Anti-Doping Agency (WADA). Growth hormone secretagogues, releasing factors, and HPG axis modulators including kisspeptin and kisspeptin analogues on the prohibited list — peptide hormones, growth factors, related substances, and mimetics, in-competition and out-of-competition ban. WADA Prohibited List. 2026. (WADA prohibited list; kisspeptin and other HPG axis modulators that stimulate endogenous testosterone production (including kisspeptin-10, kisspeptin-54, and other kisspeptin receptor agonists) may be classified as prohibited substances under the category of "peptide hormones, growth factors, related substances, and mimetics" or "hormone and metabolic modulators," due to their potential to stimulate endogenous LH/testosterone production (which could be used for performance enhancement in sports, similar to other testosterone-stimulating peptides like GHRP compounds and GnRH agonists); the exact regulatory classification of kisspeptin may vary by year and jurisdiction, but athletes should be aware that kisspeptin administration could potentially result in anti-doping violations due to its ability to alter the endogenous steroid profile and stimulate testosterone production; detection methods may include measurement of LH/testosterone changes and the biological passport, as well as direct detection of synthetic kisspeptin peptides in blood/urine; provides regulatory context for kisspeptin-10 as a potentially banned performance-enhancing substance in sports)