Reference
The families of research peptides
Thirty-five compounds sort into about a dozen families, and most of the confusion in this field comes from compounds being grouped by what they are sold beside rather than by what they are.
A family here means structural kinship — a shared parent molecule, a shared design approach, or a shared receptor target. It says what a compound resembles, not what it does to anyone.
Incretin analogues
Analogues of gut hormones — GLP-1, GIP, or both at once. Distinguished by how many receptors a single chain is designed to address: one, two, or three.
Amylin analogues
A separate hormone family from the incretins, frequently discussed alongside them. Their design is dominated by preventing the aggregation natural amylin is prone to.
Growth hormone secretagogues and GHRH analogues
Two related approaches: analogues of growth hormone-releasing hormone, and designed molecules that act at the same system. Their shared -relin ending is not a coincidence.
Melanocortins
Built on alpha-melanocyte-stimulating hormone, whole or in part. The most tangled family here: Melanotan II is the parent of PT-141, and KPV is the last three residues of the hormone they all derive from.
Thymosins
Named for the thymus, where both were first found — and otherwise unrelated. Thymosin alpha-1 is a natural 28-residue sequence; TB-500 is a short synthetic fragment of thymosin beta-4, a different protein entirely.
Short Russian-programme peptides
A distinct research tradition: take a short sequence from a larger natural molecule, then modify it for stability. Different parent molecules, shared design philosophy.
Mitochondrial peptides
One encoded in mitochondrial DNA rather than the nucleus, one designed to associate with a mitochondrial membrane lipid. Related by destination rather than by origin.
Copper and cosmetic peptides
Short chains used largely in the cosmetic sector. GHK-Cu carries a copper ion as part of the complex, which is why its powder is blue.
Designed and single-origin peptides
Compounds that do not sit in a larger family here — each from its own parent molecule or its own design programme.
- What is BPC-157?
- What is FOXO4-DRI?
- What is Kisspeptin-10?
- What is Oxytocin Acetate?
- What is DSIP?
- What is Adamax?
- What is Glutathione?
Blends
Several compounds freeze-dried together in one vial and documented as a single batch. A packaging arrangement, not a new molecule.
Not peptides at all
Sold alongside peptides and belonging to entirely different chemical classes. Concepts such as net peptide content and peptide purity apply to these differently, or not at all.
- What is NAD+?
- What is Melatonin?
- What is SLU-PP-332?
- What is 5-Amino-1MQ?
- What is Bacteriostatic Water?
Why the grouping matters
Compounds get discussed together because they are sold together, and that is not the same relationship. Cagrilintide is routinely mentioned beside the GLP-1 analogues and is a different hormone family — its name says so outright. The two thymosins share a name and nothing else. Three things in this range are not peptides.
Reading the family correctly is the difference between knowing what a compound is and knowing what shelf it was on.
