GHK-Cu

TB-500 is a synthetic peptide that copies the active region of thymosin beta-4, a natural protein that controls how cells build and move their internal skeleton. Most TB-500 products reproduce the short LKKTETQ sequence (residues 17 to 23) responsible for binding actin and driving cell migration, which is why it gets marketed for tendon, muscle, and wound repair. Here is the honest part: there are essentially no completed human trials of the TB-500 fragment itself, and almost all the human clinical data is for the full-length thymosin beta-4 molecule, which is related but not the same thing.

BPC-157 is a synthetic 15-amino-acid peptide (sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) based on a fragment of a protective protein found in human gastric juice. It is studied almost entirely in animals for tendon, ligament, gut, and tissue healing, and it has racked up hundreds of preclinical papers. The catch: it is not approved by any regulator for any use, and the human evidence is a handful of small pilot studies, not real clinical proof.

Matrixyl is the trade name (Sederma) for palmitoyl pentapeptide-4, also written Pal-KTTKS, a collagen-fragment peptide attached to a fatty acid so it can cross skin. Unlike Botox-mimic peptides, it does not touch muscle: it signals skin cells to rebuild collagen, so it is aimed at fine lines, firmness and skin texture rather than expression wrinkles. It is a cosmetic ingredient with one of the better-documented topical studies in the peptide space, though far short of drug-grade proof.

Matrixyl 3000 is Sederma's follow-up to the original Matrixyl, a fixed pair of two fatty-acid-tagged peptides: palmitoyl tripeptide-1 (Pal-GHK) and palmitoyl tetrapeptide-7 (Pal-GQPR). The idea is a one-two punch: one peptide tells skin to rebuild collagen, the other calms the low-grade inflammation that wears collagen down. It is a cosmetic ingredient aimed at firmness, fine lines and aging skin, with supportive but mostly company-generated evidence.

AHK-Cu is a synthetic copper-bound tripeptide, alanine-histidine-lysine complexed with a copper ion, engineered mainly for hair and scalp products. It is the lesser-known sibling of the naturally occurring GHK-Cu copper peptide, designed in the lab specifically to push hair follicles to keep growing. It is a cosmetic and research ingredient, not an approved hair-loss drug, and its evidence is essentially limited to one notable lab study.

SNAP-8 (Acetyl Octapeptide-3) is a synthetic eight-amino-acid topical cosmetic peptide, an extended cousin of Argireline that adds two residues to the same SNAP-25 mimic sequence. It is marketed as a needle-free way to soften expression lines, especially on the forehead and around the eyes. It is a cosmetic ingredient, not an approved drug, and the human evidence behind it is thin and mostly comes from the manufacturer.