What are peptides? A simple guide to skincare, supplements and medicines
Peptides are chains of amino acids—the building blocks also found in proteins. But a peptide serum, a collagen powder and a prescription medicine are not three versions of the same thing. Start by finding out which one you are looking at. [1]
In this guide
Why is everyone talking about peptides?
The word appears across beauty routines, nutrition and medicine. That makes it easy to mistake interest in one category for proof about another. A useful first question is: does this product go on the skin, get taken as a supplement, or require medical care?
Peptides in skincare
A finished peptide serum or moisturizer is made for topical use. Research on one moisturizer containing palmitoyl pentapeptide found improvements in photoaged skin over 12 weeks. That supports investigating particular formulas, not assuming every product with “peptide” on the label works alike. [2]
Collagen peptides in supplements
Collagen peptides are fragments of collagen protein. Some trials report skin benefits, but a 2025 review found that results depended on study quality and funding. Treat a supplement as a product to evaluate, not a guaranteed route to a celebrity’s appearance. [3]
Peptide medicines and research products
Some peptides are used in prescription medicines; other compounds remain research materials. A shared ingredient name does not make a research vial interchangeable with a finished medicine. US FDA guidance specifically warns about unapproved GLP-1 products marketed for human use. [4]
Your first practical step
Choose the category before choosing the brand. Write down the exact product name, intended use and result you want. Then look for human research on that product or formulation. If the claim is medical, take those details to a licensed clinician.
Sources & further reading
- IUPAC: What is a peptide?
- Robinson et al.: controlled palmitoyl pentapeptide study (2005)
- Myung and Park: collagen trials, funding and study quality (2025)
- FDA: concerns with unapproved GLP-1 products (US guidance)
Educational information; not a personalized treatment plan. Celebrity references are editorial, not endorsements of Prosper. No independent medical review is claimed.