PT-141, also known as Bremelanotide, was derived from a synthetic melanocortin analog known as Melanotan 2 (MT-2). A melanocortin analog, such as PT-141 and MT-2, is considered to be any synthetic compound designed to mimic or influence the functions of natural melanocortin peptides. These peptides, such as the alpha-melanocyte stimulating hormone (α-MSH), may be involved in a range of physiological processes including appetite regulation, energy homeostasis, immune responses, and skin cell pigmentation. PT-141 is a melanocortin analog that was developed to interact with Melanocortin-4 Receptor (MC-4R). It has been studied for a variety of potential characteristics and bioactivities through its interaction with this receptor. Apart from MC-4R, there are other melanocortin receptors like MC-1R, MC-2R, MC-3R, and MC-5R, each associated with different potential functions. For instance, MC-1R may be primarily involved in skin cell and hair follicle pigmentation, MC-2R appears to play a crucial role in the adrenal axis and stress response, MC-3R is implicated in the regulation of energy homeostasis, and MC-5R has been linked to exocrine function and thus impacts processes such as sweating and sebum production.

Ipamorelin is a small pentapeptide that binds to the receptor of ghrelin/growth hormone secretagogue (GHS), and is speculated to trigger the release of growth hormone via pituitary cells. Research has suggested the peptide to be selective in its mode of action.^[1] Ipamorelin, researchers report, does not appear to induce non-specific release of hormones like prolactin, thyroid-stimulating hormone, ACTH, luteinizing hormone, follicle-stimulating hormone, or cortisol. The high specificity of the peptide makes it an ideal model for the study of selectivity in receptor binding. It appears to function through interaction with cognate receptors on the target cell surface and mediates a cellular response. Ipamorelin may induce secretions from the pituitary gland, promoting growth in animal study models.^[2] In addition, it may not only trigger the expression of insulin-like growth factor-1(IGF-1) but may also inhibit the secretion of somatostatin. IGF-1 is considered to be the main anabolic mediator of growth hormone.

Specifications

Molecular Formula: C₄₇H₅₈N₁₂O₆

Molecular Weight: 887.05 g/mol

Sequence: His-2-Me-D-Trp-Ala-Trp-D-Phe-Lys-NH2

GHK is a copper peptide that occurs naturally in a copper complex of the tripeptide glycyl-L-histidyl-L-lysine. It has two variants — GHK with or without Cu. GHK appears to have a strong affinity for copper (II), and it is synthesized naturally from plasma, although it has been isolated in other areas. In cases of injury, GHK may be released from tissue cells. The copper peptide appears to affect genes that control injury and stress responses. Its functions appear to include the following: tissue remodeling, anti-inflammatory response, pain perception inhibition, nootropic action anti-cancer action, blood vessel growth, and nerve outgrowth. A decrease in the regenerative capacity of an organism may be traced to a decline in GHK-level. Its potential functions extend to infection control, follicle growth, collagen and elastin production increases, tissue repair, and glycosaminoglycan synthesis. Endogenous GHK production is considered to decline over time.

Kisspeptin-10 is a peptide fragment derived from the full-length Kisspeptin (also referred to as Kisspeptin-54 or Metastin). Specifically, Kisspeptin-10 is a fragment containing the 45-54 sequence from the larger parent molecule. Research into this peptide has suggested that the compound may act as a mediator of endocrine signaling between various endocrine cells.

Originating from the KISS1 gene, which is thought to play a critical role in reproductive cell signaling and physiology, Kisspeptin-10 is particularly interesting to researchers for its potential to influence the secretion of gonadotropin-releasing hormone (GnRH). This, in turn, may affect the release of other reproductive hormones from cells with receptors for GnRH. In addition, researchers posit that the compound may potentially impact the development and regulation of blood vessels and renal function, and some studies have suggested it may mitigate cancer cell proliferation and metastasis.

Semax is a synthetic analog of adrenocorticotropic hormone (ACTH) comprising the amino acids 4 through 10 of ACTH. Semax has primarily been implicated in research on cognitive impairment and stroke. The peptide has also been studied closely within the context of dementia and certain inflammations of the optic nerve. Researchers posit that the peptide may exert neurotrophic action, suggesting that the peptide may act to increase the production of brain-derived neurotrophic factor (BDNF) in the central nervous system, with potential consequences in serotonin and dopamine release. Some researchers also suggest that Semax may interact with serotonin and enkephalin levels in the central nervous system.

PE-22-28 is a synthetic variant of the naturally occurring peptide Spadin. Spadin is a secreted peptide obtained from Sortilin. It appears to act as an antagonist of the TREK-1 (TWIK-related-potassium channel) receptor, a two-pore potassium channel identified as a potential target in the context of depression research and as a possible neurogenic regulator. Studies in mice have suggested that TREK-1 receptor deletion may make them resistant to depressive behavior and corresponding chemical imbalances in the brain.^[1] PE-22-28 represents a shorter seven amino acid synthetic Spadin analog with potentially higher efficacy and stability. Research in animal models is ongoing.