When you look at skincare ingredient lists, the word "peptide" appears frequently. But what exactly are peptides?
Peptides are "small fragments" of proteins
A peptide is a short chain of 2 to 50 amino acids. Proteins are chains of hundreds to thousands of amino acids, and peptides are their "small fragments."
Our skin’s collagen and elastin are also made of proteins. Peptides are closely related to these building blocks.
Why are they used in skincare?
The key feature of peptides is their ability to "send messages" to skin cells. For example, certain peptides signal the skin to "produce more collagen."
Moreover, since peptides are smaller than proteins, they penetrate the skin more easily. Large proteins like collagen cannot pass through the stratum corneum, but peptides can.
Not all peptides are the same
Importantly, there are many types of peptides. Some promote collagen production, some relax facial muscles, some deliver metal ions -- each with different specialties.
Just seeing "contains peptides" doesn’t tell you what effects to expect. What matters is knowing "which type of peptide is included, and for what purpose."
References
Key peer-reviewed sources behind the scientific statements in this article.
- Lupo MP, Cole AL. Cosmeceutical peptides. Dermatol Ther. 2007;20(5):343-349. PubMed
- Errante F, Ledwoń P, Latajka R, Rovero P, Papini AM. Cosmeceutical Peptides in the Framework of Sustainable Wellness Economy. Front Chem. 2020;8:572923. PubMed