Category Archives: Nootropics & Neuropeptides

Selank is a synthetic regulatory heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), synthesized by joining the natural immunomodulatory tetrapeptide Tuftsin (TKPR) to the metabolic stabilizing tripeptide Pro-Gly-Pro (PGP). Developed as a neuro-anxiolytic peptide, Selank modulates GABAergic and serotonergic neurotransmission without causing sedation, motor impairment, or physical dependence.

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), developed by the Institute of Molecular Genetics of the Russian Academy of Sciences. Engineered as an analogue of the ACTH(4-10) fragment stabilized with a C-terminal Pro-Gly-Pro tripeptide, Semax provides profound neuroprotective and cognitive-modulating actions without stimulating peripheral adrenal corticosteroid secretion.

Melanotan 2 (MT-2) is a synthetic cyclic lactam heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH). Engineered originally at the University of Arizona to protect against ultraviolet (UV) radiation-induced skin damage, Melanotan 2 functions as a potent, non-selective agonist across multiple melanocortin receptor subtypes (MC1R, MC3R, MC4R, MC5R).

Sourcing PT 141 for sale in research marketplaces requires careful verification of cyclic lactam integrity. The molecule relies on an internal covalent lactam bond between the side chains of Asp-3 and Lys-8. If this cyclization step is incomplete during solid-phase synthesis, the resulting linear peptide exhibits virtually zero binding affinity to central melanocortin receptors.

PT 141, chemically known as Bremelanotide, is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH). Unlike peripheral phosphodiesterase-5 (PDE-5) inhibitors (such as sildenafil) that act purely downstream via vascular smooth muscle relaxation, PT 141 acts centrally within the central nervous system to stimulate sexual arousal and libido pathways.