This page is a quick reference, not a new explanation. Every peptide named across our guides is listed here with a one-line summary of what it actually does and a link to the full breakdown, where one exists. If you already know which ingredient you’re looking for, start here. If you’re new to the topic, What Are Peptides? A Beginner’s Guide is the better starting point.
Topical Peptides (Skincare)
GHK-Cu (Copper Tripeptide-1)
Category: carrier peptide. Binds and delivers copper, a trace mineral, to skin cells to support maintenance and repair processes. One of the longer-researched peptides in skincare. Full guide: Copper Peptides (GHK-Cu) Explained.
Palmitoyl Pentapeptide-4
Category: signal peptide. Mimics a collagen fragment your skin recognizes as part of its own repair process, supporting collagen production. Often sold under a proprietary branded name. Full guide: Palmitoyl Pentapeptide-4 Explained.
Acetyl Hexapeptide-8
Category: neurotransmitter-inhibiting peptide. Interferes with the signaling behind small, repeated muscle contractions, softening the look of expression lines with consistent use. Not equivalent to an injectable treatment, despite marketing comparisons. Full guide: Acetyl Hexapeptide-8 Explained.
Enzyme-Inhibiting Peptides
Category: enzyme-inhibiting. A less commonly marketed group that slows the breakdown of existing collagen rather than stimulating new production. Appears more often in higher-end or specialized formulations than in mainstream products. Covered in Signal, Carrier, and Neurotransmitter-Inhibiting Peptides: A Field Guide; no single named ingredient in this category has a dedicated guide yet.
Oral Peptides (Supplements)
Hydrolyzed Collagen Peptides
Category: oral supplement. Collagen broken down during manufacturing into smaller peptide fragments, making it easier to digest and absorb than intact collagen protein. The most common form used in skin, hair, and general collagen supplements. Full guide: Collagen Peptides Explained.
Marine, Bovine, and Plant-Based Collagen
Category: oral supplement, by source. Marine collagen comes from fish and is predominantly Type I; bovine collagen comes from cattle and includes a mix of Type I and Type III; plant-based formulas supply amino acids and cofactors to support the body’s own collagen production rather than supplying collagen peptides directly. Full guide: Marine vs. Bovine vs. Plant-Based Collagen.
Undenatured Type II Collagen
Category: oral supplement, joint-specific. A differently processed form of collagen, thought to work partly by interacting with the immune system’s response around cartilage rather than only supplying raw material. Used specifically in joint-focused formulas, distinct from the hydrolyzed collagen more commonly used for skin. Covered in Peptides for Joint and Cartilage Health.
How to Use This Glossary
Match the name on your product label to the entries above rather than relying on the word “peptide” alone, a point covered throughout this series and most directly in How to Choose a Peptide Serum. If a product lists a peptide not covered here, check the functional category framework in our field guide to understand roughly what job it is likely doing, based on its name and where it falls in that classification.
This glossary will grow as we cover more named peptides in future guides. For the regulatory and safety framework that applies to every ingredient listed here, see Are Peptides Safe? What the Science (and Regulation) Actually Say.
Related Guides
Wellness Science
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Peptides are one of the most common actives in modern serums, but the label rarely explains what they actually do once they touch skin. Here is the real function, ingredient by ingredient category.
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