Acetyl tetrapeptide-5
is used in cosmetic eye formulations to decrease puffiness, eye bags, and dark circles by reducing edema and protecting proteins such as SOD from glycation
Alanine
Ala / A · hydrophobic residue · neutral charge
AOD-9604
is studied as an anti-obesity peptide that can reduce weight gain and increase fat oxidation in obese animal models with generally neutral effects on IGF-1 and glucose metabolism in early human trials
Arginine
Arg / R · basic residue · positive charge
Argireline
is a topical cosmetic peptide reported to decrease dynamic wrinkles by partially mimicking the mechanism of botulinum toxin in a non-invasive manner
Asparagine
Asn / N · polar residue · neutral charge
Aspartic acid
Asp / D · acidic residue · negative charge
BPC-157
is investigated for accelerating healing of gastrointestinal mucosa, tendons, ligaments, bone, and nervous tissue in preclinical models, with anti-inflammatory and pro-angiogenic effects
Comparison
While Kisspeptin is a key regulator of the hypothalamic–pituitary–gonadal axis, controlling puberty and fertility; kisspeptin-10 also inhibits trophoblast invasion and tumor metastasis in experimental models339199, Melanotan I is approved in some regions for prevention of phototoxicity in erythropoietic protoporphyria and is studied as a skin-darkening, photoprotective peptide3444.
While Kisspeptin works as a family of peptides (eg, kisspeptin-10, -13, -14, -54) derived from the KISS1 precursor that activate G-protein–coupled receptor KISS1R (GPR54), triggering GnRH release and regulating pubertal onset and reproductive axis activity339199, Melanotan I is a linear 13-amino-acid analog of α-MSH (afamelanotide) that selectively activates MC1R on melanocytes, increasing eumelanin synthesis and providing photoprotection3444.
Kisspeptin
KISS1
Melanotan I
POMC
Both peptides fall into a similar broad context as Hormone peptides, although the details of how they are used and discussed still diverge. Their typical research and application settings separate fairly clearly: Kisspeptin is more often discussed in the realm of Reproductive health, whereas Melanotan I is more often associated with the realm of Dermatology and aesthetics. Both appear to work through Receptor agonist, but the functional emphasis still separates, with Kisspeptin leaning toward and Melanotan I leaning toward Melanogenesis modulation. Kisspeptin has a more natural endogenous origin, while Melanotan I is closer to synthetic analog background with Kisspeptin in Preclinical development and Melanotan I approved for Research use only. Kisspeptin carries amidation features, while Melanotan I instead reflects d-amino acid substitution changes, while their sequence patterns also diverge, with Kisspeptin showing alpha-helical domain features and Melanotan I showing protein-mimetic sequence features.