Peptide Glossary

Selank modulates the GABAergic system and influences the expression of brain-derived neurotrophic factor (BDNF). It inhibits enkephalin-degrading enzymes, prolonging the action of endogenous opioid peptides, and has been shown to regulate serotonin metabolism and IL-6 cytokine expression. Unlike benzodiazepines, it does not bind directly to GABA-A receptors, which accounts for its non-sedating profile.

Semax stimulates the expression of BDNF and its receptor TrkB in the hippocampus and cortex, potentiating neurotrophin signaling pathways critical for synaptic plasticity. It also modulates dopaminergic and serotonergic neurotransmission, inhibits prolyl endopeptidase (which degrades neuropeptides), and exhibits antioxidant activity by reducing oxidative stress markers in neural tissue.

MOTS-C activates AMPK (AMP-activated protein kinase) signaling, the master regulator of cellular energy homeostasis. It inhibits the folate cycle and de novo purine biosynthesis, leading to AICAR accumulation and downstream AMPK activation. Under exercise or metabolic stress, MOTS-C translocates from mitochondria to the nucleus, where it binds ARE (antioxidant response elements) and regulates stress-response gene expression.

Kisspeptin binds the KISS1R (GPR54) receptor on GnRH neurons in the hypothalamus, triggering GnRH pulse generation. GnRH then stimulates pituitary release of LH (luteinizing hormone) and FSH (follicle-stimulating hormone), which drive gonadal steroidogenesis. Kisspeptin neurons in the arcuate nucleus (KNDy neurons, co-expressing NKB and dynorphin) form the GnRH pulse generator, making kisspeptin central to the neuroendocrine control of reproduction.

MT-II activates melanocortin receptors across multiple tissues. MC1R activation in melanocytes stimulates eumelanin synthesis, producing skin darkening. MC4R activation in the hypothalamus suppresses appetite and modulates energy expenditure. MC4R signaling in the spinal cord and brain mediates pro-erectile effects via the nitrergic pathway. The cyclic structure and D-Phe substitution confer resistance to enzymatic degradation and increased receptor binding affinity versus native α-MSH.

NAD+ participates in over 500 enzymatic reactions. As an electron acceptor in glycolysis and the TCA cycle, it is reduced to NADH, driving ATP synthesis via oxidative phosphorylation. As a substrate for sirtuins (SIRT1–7), it enables deacetylation of histones and metabolic enzymes, regulating gene expression, mitochondrial biogenesis, and stress responses. PARP1 consumes NAD+ for DNA repair, and CD38 hydrolyzes NAD+ to cyclic ADP-ribose for calcium signaling.

Methylcobalamin serves as a cofactor for methionine synthase, converting homocysteine to methionine and regenerating tetrahydrofolate for nucleotide synthesis. It also acts as a cofactor for methylmalonyl-CoA mutase in the mitochondria, enabling propionate metabolism. In neural tissue, B12 is required for myelin basic protein synthesis and axonal transport. Deficiency leads to subacute combined degeneration of the spinal cord, megaloblastic anemia, and elevated homocysteine.

The acidic environment (pH ~3.5) protonates basic amino acid residues (lysine, arginine, histidine), increasing peptide solubility through electrostatic repulsion between peptide chains. This prevents aggregation of hydrophobic peptides that would otherwise precipitate in neutral aqueous solution. Once reconstituted, the solution is typically diluted with bacteriostatic water or saline to achieve the desired concentration and raise the pH toward physiological range.

Benzyl alcohol (0.9% w/v) acts as a bacteriostatic agent by disrupting bacterial cell membrane integrity and inhibiting bacterial enzyme systems. It does not sterilize the solution but prevents bacterial proliferation between uses. The neutral pH (~5.7) is compatible with most peptides and proteins. Unlike sterile water for injection (SWFI), BAC water allows multi-dose use of reconstituted peptides without the risk of microbial contamination from repeated needle insertions.

Tesamorelin binds the GHRH receptor on pituitary somatotrophs with high affinity, stimulating GH synthesis and pulsatile release via the Gs/cAMP/PKA pathway. The N-terminal trans-3-hexenoic acid modification confers resistance to DPP-IV cleavage, extending the half-life to approximately 26 minutes versus under 7 minutes for native GHRH(1-44). Downstream GH signaling drives hepatic IGF-1 production, which mediates lipolysis in visceral adipocytes via hormone-sensitive lipase activation.

GLP-3 is derived from the same proglucagon precursor as GLP-1 and GLP-2 through tissue-specific post-translational processing by prohormone convertase 1/3 (PC1/3) in intestinal L-cells. Its receptor pharmacology and downstream signaling pathways are an active area of investigation. Structural homology with GLP-1 suggests potential interaction with incretin-related receptors, though its specific receptor has not been fully characterized in the published literature.

Glutathione functions as a direct free radical scavenger, reducing reactive oxygen species (ROS) and reactive nitrogen species (RNS) through its thiol group. It serves as a cofactor for glutathione peroxidases (GPx), which reduce hydrogen peroxide and lipid hydroperoxides. Glutathione S-transferases (GSTs) conjugate GSH to electrophilic xenobiotics for hepatic detoxification. In its reduced form (GSH), it maintains protein thiols and regenerates vitamins C and E. Oxidized glutathione (GSSG) is recycled to GSH by glutathione reductase using NADPH.

SS-31 binds cardiolipin — a phospholipid unique to the IMM — through electrostatic and hydrophobic interactions. This interaction stabilizes cardiolipin structure, preserving the cristae architecture required for efficient electron transport chain (ETC) function. By reducing cardiolipin peroxidation, SS-31 prevents cytochrome c release (a trigger of apoptosis) and maintains Complex I, III, and IV activity. It also scavenges mitochondrial ROS directly via the dimethyltyrosine (Dmt) residue, reducing superoxide and hydrogen peroxide without consuming antioxidant cofactors.

IGF-1 LR3 binds the IGF-1 receptor (IGF1R) — a receptor tyrosine kinase — with high affinity, activating the PI3K/Akt/mTOR and Ras/MAPK/ERK signaling cascades. These pathways drive protein synthesis, cell proliferation, glucose uptake (via GLUT4 translocation), and inhibition of apoptosis. The reduced IGFBP binding of LR3 means a far greater fraction of the administered dose remains bioavailable versus native IGF-1, which is >99% IGFBP-bound in circulation.

GH binds the GH receptor (GHR) — a class I cytokine receptor — inducing receptor dimerization and activation of JAK2 kinase. JAK2 phosphorylates STAT5b, which translocates to the nucleus to drive IGF-1 gene transcription in the liver. GH also activates the MAPK/ERK and PI3K/Akt pathways directly in peripheral tissues. Metabolically, GH promotes lipolysis via hormone-sensitive lipase activation, stimulates gluconeogenesis, and has anti-insulin effects on glucose uptake in adipose tissue.

The combination engages two complementary pathways simultaneously. CJC No DAC activates the GHRH receptor (Gs/cAMP/PKA pathway) to drive GH gene transcription and vesicle exocytosis. Ipamorelin activates GHS-R1a (Gq/PLC/Ca²⁺ pathway) to trigger GH release and suppress hypothalamic somatostatin. The dual-pathway activation produces GH area-under-curve values 2–10× greater than either compound alone in rodent models, while preserving the pulsatile pattern of endogenous GH secretion.

Epithalon appears to upregulate hTERT (human telomerase reverse transcriptase), the catalytic subunit of telomerase, enabling the enzyme to add telomeric repeats to chromosome ends and counteract age-related telomere shortening. Additionally, research suggests Epithalon influences chromatin remodeling — specifically histone H3 and H4 acetylation in heterochromatin regions — partially restoring epigenetic patterns associated with younger cells. It also appears to act as a bioregulator of pineal function, stimulating melatonin synthesis and helping restore circadian signaling in aged subjects.

BPC-157 upregulates growth hormone receptor expression in tendon fibroblasts and promotes the formation of new blood vessels (angiogenesis) via the nitric oxide (NO) pathway. It modulates the VEGF signaling cascade, accelerating vascularization at injury sites. In the gastrointestinal tract, it protects mucosal integrity by counteracting NSAID-induced damage and stimulating the production of cytoprotective prostaglandins. BPC-157 also exhibits dopaminergic and serotonergic modulatory activity, contributing to its observed effects on mood and stress resilience in animal models.