The science behind the catalog

Growth-hormone-releasing hormone is a 44-amino-acid hormone made in the hypothalamus. It binds the GHRH receptor on the pituitary, which is the switch for growth-hormone release. Each compound in this family is a version of that hormone, differing in how much of the sequence is kept and how it is protected from enzymes. Sermorelin keeps the first 29 residues — the shortest piece that still activates the receptor. Tesamorelin keeps all 44 and adds a chemical group at one end to slow breakdown. CJC-1295 DAC adds a group that latches onto albumin in blood, extending its life from minutes to days.

• Sermorelin — First 29 residues — the minimum active fragment
• Tesamorelin — Full 44 residues, chemically protected
• CJC-1295 DAC — Albumin-binding, long-acting

Ghrelin is the hormone best known for signalling hunger, and it acts at a receptor called GHS-R1a. That receptor also sits on the pituitary and influences growth-hormone release — by a separate route from the GHRH receptor (see GHRH analogues). Ipamorelin is a five-amino-acid synthetic that activates GHS-R1a selectively, which is what makes it useful as a laboratory tool: it isolates that one pathway from the others. Because the two families act on different receptors, they are frequently studied together, and that is why one of the blends pairs them.

• Ipamorelin — Selective GHS-R1a pentapeptide

Growth hormone does much of its work indirectly: it prompts the liver to produce insulin-like growth factor 1, a 70-amino-acid protein that carries the signal onward. In the body IGF-1 is held in check by binding proteins that switch it off. IGF-1 LR3 is an engineered version with a 13-residue extension and one substitution at position 3, changes that sharply reduce that binding. It sits downstream of the GHRH-analogue and ghrelin-receptor families rather than alongside them.

• IGF-1 LR3 — Engineered analogue, reduced binding-protein affinity

The cytoskeleton is the internal scaffolding a cell uses to hold its shape and to move. Thymosin β4 is a protein that helps manage it by binding actin; the TB-500 in our blend is listed by its supplier as thymosin β4 itself (CAS 77591-33-4). BPC-157 is a fifteen-residue sequence reported by its originating laboratory as part of a larger protein in gastric juice — a parent that has not been independently isolated. The two are unrelated in sequence but are studied in overlapping assays, which is why they appear together in a blend.

• BPC-157 — 15 residues; reported gastric-protein fragment
• BPC-157 / TB-500 Blend — Supplied together as a blend

Alpha-melanocyte-stimulating hormone is a 13-residue hormone involved in pigmentation and in inflammatory regulation. Its final three residues — lysine, proline, valine — retain activity in inflammatory signalling assays without the pigmentation activity of the whole hormone. That separation is exactly why the fragment is useful in the laboratory: it isolates one arm of the hormone's behaviour.

• KPV — Residues 11-13 of alpha-MSH

Some short peptides bind metal ions tightly enough that the complex, not the peptide alone, is the molecule of interest. GHK is three amino acids found in human plasma; it binds copper(II) with high affinity, and the resulting complex is what laboratories study in extracellular-matrix and connective-tissue work. Written GHK-Cu, the suffix denotes the bound copper.

• GHK-Cu — Glycyl-histidyl-lysine with bound copper(II)

This is a design family rather than a biological one, and it is a neat piece of chemistry. Short peptides are broken down quickly by enzymes in the body. Researchers in Russia addressed this by attaching a proline-glycine-proline tail, which resists that breakdown. Semax applies it to a fragment of adrenocorticotropic hormone; Selank applies it to tuftsin, a fragment of an antibody molecule. The starting fragments are unrelated — the shared tail is what makes them siblings.

• Semax — ACTH fragment + Pro-Gly-Pro
• Selank — Tuftsin + Pro-Gly-Pro

Almost every protein in a cell is coded by nuclear DNA. Mitochondria carry a small separate genome, and a handful of short peptides are encoded within it — a class only identified in the last two decades. MOTS-c, sixteen residues coded inside the 12S ribosomal RNA gene, was among the first. It is studied as a signalling molecule between the mitochondria and the rest of the cell.

• MOTS-c — Encoded in the mitochondrial 12S rRNA gene

Incretins are gut hormones released after eating that act on receptors regulating metabolism. A long-running line of research has built synthetic peptides that activate more than one of these receptors from a single molecule. Retatrutide is a triple agonist — GIP, GLP-1 and glucagon receptors together — and carries a fatty-acid modification that extends its half-life. It is investigational and has not been approved by any regulatory authority.

• Retatrutide — GIP / GLP-1 / glucagon triple agonist

NAD+ is not a peptide and has no amino acids in it. It is a coenzyme present in every living cell, carrying electrons between chemical reactions and acting as a substrate for enzyme families including the sirtuins and PARPs. It appears in this catalog as a standard laboratory reagent rather than as a member of any peptide family.

• NAD+ — Nicotinamide adenine dinucleotide