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The Difference Between Amino Acids, Peptides, and Polypeptides

Keep reading for the full lowdown on amino acids, peptides, and polypeptides, and why you might want to add them to your routine. 

Much like retinal (with an A!) and niacinamide, amino acids, peptides, and polypeptides have become widely popular on skincare ingredient lists in recent years—and with good reason. You probably heard about amino acids and peptides quite a lot already, but what about polypeptides? Keep reading for the full lowdown on what’s so different about each of these ingredients and why they’re worth adding to your arsenal, ASAP. 

What are polypeptides?

As Youth To The People’s Director of Field Sales + Education, Jacob Tomás del Rosario, explains: “A polypeptide is a chain of multiple amino acids linked together by peptide bonds. Think of it as a beaded necklace—yes like the ones you and your friends used to make during sleepovers in the 90s—the whole necklace is the polypeptide while the beads are the amino acids.” What makes polypeptides so special is the fact that there are a lot of different amino acid building blocks to pick from, and that these amino acids can be organized in many ways. This results in many different polypeptides, each with different properties.

What are peptides?

Peptides are similar to polypeptides in that they are also made up of amino acids linked together, but they are smaller. As del Rosario explains, “peptides are shorter chains of two or more amino acids, while polypeptides are longer chains made up of many more amino acids.” Just like with polypeptides, there are many different peptides out there, and quite a few are used in skincare products. 

“Depending on their amino acid sequence, peptides can have different properties,” says del Rosario. “Some peptides have been shown to be beneficial in helping visibly firm skin, some in improving the appearance of fine lines and wrinkles, some in boosting skin smoothness,” and the list goes on. 

What are amino acids?

Amino acids are the building blocks of peptides and polypeptides. 

“Some amino acids can help hydrate the skin, potentially improving the appearance of dry skin and fine lines,” explains board-certified dermatologist Dr. Marisa Garshick, M.D. “Many different amino acids are used in skincare. Some that you can find on product ingredient labels are glycine, arginine, lysine, histidine, and leucine.” 

How do amino acids, peptides, and polypeptides differ?

As described above, amino acids are linked together to form both peptides and polypeptides. 

“Peptides and polypeptides differ in terms of size and number of amino acids,” says Dr. Garshick. In our body, amino acids, peptides, and ultimately polypeptides are the building blocks of proteins, for example, the collagen and elastin proteins in your skin. However, proteins are much more than simple combinations of these building blocks, they are extremely complex 3D assemblies. Together with their amino acid constituents, this complex structure is what ultimately dictates their function in the body.

The bottom line?

At the end of the day, amino acids, peptides, and polypeptides are all interconnected and have the potential to offer an array of different skincare benefits, from helping visibly firm skin to improving the appearance of fine lines and wrinkles and boosting skin smoothness. All this to say, these ingredients are worth adding to your skincare lineup, stat. 

For more on polypeptides and why we’re so excited about them, click here

Written by Kaleigh Fasanella for Youth To The People

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