If you are any kind of skincare junkie like I am, you've definitely heard of peptides being used in various anti-aging products, claiming to solve pretty much every skin flaw imaginable.
But what exactly are peptides? And how do they work?
In pharmacy school, I only learned about peptides as they relate to the mechanism of action of various medications. So understanding the role of peptides in skincare is something fairly new to me also!
But ever since I learned that peptides are the reason why my favorite eye cream can make my crows feet disappear and why my lips look so plump after applying my nightly lip serum, I just had to learn more. So after doing my research I've written this post to teach you all about the role of peptides in skincare!
What are peptides?
In simple terms, peptides are fragments of proteins.
Peptides are formed when amino acids bond together. For example, when two amino acids are joined together by a single bond it is called a dipeptide. Three linked amino acids are a tripeptide, followed by tetrapeptides, etc.
Many people ask what the difference is between peptides and protein. While they are both made of the same building blocks (amino acids), it all comes down to size. Peptides typically contain approximately 50 or fewer amino acids. Proteins consist of 50 or more amino acids and can be made of polypeptides (a long peptide chain).
The role of peptides in skincare
The reason why peptides are used in anti-aging skincare products is due to their ability to increase collagen production. Collagen is the protein that gives your skin a firm, smooth, youthful appearance. Natural and environmental factors, like sun exposure and free radicals, cause collagen to degrade over time. The result? Lines, wrinkles, and sagging skin. Therefore, since peptides can increase collagen production they are able to minimize these signs of aging. While many clinical studies have proven this to be true, the mechanism(s) by which peptides accomplish this is still unclear. [Related Post: What is Collagen?]
Controversy exists over whether peptides actually work in skincare products because their size breaks the 500 Dalton Rule. According to this rule, a substance can only be absorbed into the skin if its molecular weight (MW) is under 500 Daltons. So if peptides are larger than 500 Daltons, how can peptides even work if they aren't absorbed by the skin?
One theory is that peptides work through signaling. Cells have the ability to communicate with each other to coordinate certain actions, which is known as "cell-signaling". Peptides can mimic certain cell-signaling processes. Specifically, peptides that are used in skincare products mimic the same peptides that you’d find when collagen is broken down. According to research from the National Institutes of Health (NIH), when collagen is degraded it produces peptides that signal skin cells to generate more collagen. Synthetic peptides have been developed that can mimic these naturally occurring peptides, thus causing your skin to “think” collagen is deteriorating. The result? New collagen production! Mimicking natural cell-signaling is one way that peptides can overcome the 500 Dalton rule; even though they don’t penetrate the skin barrier, they still work effectively.
Peptides to look for in skincare products
The most commonly used peptide in skincare is palmitoyl pentapeptide-3.
Palmitoyl pentapeptide-3 has been extensively studied for its ability to stimulate new production of types I and II collagen as well as fibronectin, all of which are important for the firmness and elasticity of the skin.
Another peptide that has been proven to benefit the skin is palmitoyl tetrapeptide-7.
According to a 2017 publication in Cosmetics, this palmitoyl tetrapeptide-7 serves as an anti-inflammatory after exposure to the sun's harmful UVB rays.
One of the best peptides that can benefit your skin is palmitoyl oligopeptide.
Palmitoyl oligopeptide can significantly stimulate collagen production in human fibroblasts, as shown in a 2007 study published in Dermatologic Therapy. Firmer skin can be seen when palmitoyl oligopeptide is used twice daily for a significant period of time (about six months).
My favorite peptide skincare products
Even though I've only tried a handful of peptide skincare products so far, here are a few of my faves:
REDEFINE Multi-Function Eye Cream combines powerful peptides to minimize the appearance of crow’s-feet, helps reduce the appearance of both puffiness and dark under eye circles while special optical diffusers noticeably brighten the eye area.
Rodan + Fields Lip Renewing Serum
The REDEFINE Lip Renewing Serum is rich in peptides, like Palmitoyl Tripeptide-1, as well as vitamin E, which helps lips to retain their natural moisture, visibly smooth lip texture, and reduce the appearance of lip wrinkles. I honestly wake up with full-on pouty lips after just one night of applying this product!
What are your favorite peptide products? Leave me a comment below!