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 Ipamorelin is investigated for producing moderate, physiologic-like GH pulses useful for studying anabolic, body-composition, and recovery effects with a relatively clean endocrine side-effect profile compared with earlier GHRPs16, Melanotan II is studied as a tanning and libido-enhancing agent; increases melanin production and can reduce food intake and modulate sexual arousal in animal models and humans3545.
While Ipamorelin works as a third-generation pentapeptide growth hormone secretagogue that selectively agonizes the ghrelin (GHSR-1a) receptor to trigger controlled, GH-specific pituitary release with minimal effects on cortisol or prolactin16269596, Melanotan II is a cyclic heptapeptide melanocortin analog (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2) that acts as a non-selective, high-potency agonist at MC1R, MC3R, MC4R, and MC5R, influencing pigmentation, appetite, and sexual behavior3545.
Ipamorelin
GHSR
Melanotan II
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: Ipamorelin is more often discussed in the realm of Metabolic and endocrine and Musculoskeletal health, whereas Melanotan II is more often associated with the realm of Dermatology and aesthetics and Reproductive health. Both appear to work through Receptor agonist, but the functional emphasis still separates, with Ipamorelin leaning toward Anabolic growth and Lipolysis and fat loss and Melanotan II leaning toward Melanogenesis modulation. Ipamorelin has a more synthetic design origin, while Melanotan II is closer to synthetic analog background with Ipamorelin in Preclinical development and Melanotan II approved for Research use only. Ipamorelin takes the form of a linear peptide, whereas Melanotan II is closer to a cyclic peptide, while Ipamorelin carries d-amino acid substitution and amidation features, while Melanotan II instead reflects acetylation changes.