Beauty education

What are peptides and what are they used for in skincare products?

Elise Deylgat

Peptide cosmeceuticals are one of the new, popular options to treat aging skin. But what are the pro's and con's of these products? Read more about it in this blog.

What are peptides?

When amino acids link together, they form chains called peptides. 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 fifty or fewer amino acids. Proteins consist of fifty or more amino acids and can be made of polypeptides (a long peptide chain). There are different types of peptides, all of which are made from different combinations of amino acids. They can be classified or categorized according to their source and function.

The role of peptides in and on your skin

Proteins, mainly collagen, are fundamental building blocks of human skin. Collagen homeostasis is a natural process, in which our body produces collagen and breaks it down in peptides. Collagen is produced by fibroblasts and broken down by enzymes, namely matrix metalloproteinases (MMP). When there is a good balance between production and collagen degradation, the extracellular matrix generates a beautiful, firm skin. When more collagen is broken down than produced, the firmness diminishes and wrinkles appear. Therefore, it is both important to stimulate your collagen production and to inhibit collagen fragmentation.

Collagen production

When you are young, your body produces collagen at a very high rate. However, as you age, that rate begins to slow down. After age 20, your body produces an average of 1% less collagen peptides for skin each year. Without collagen peptides, the skin does not remain intact and this results in loss of firmness, appearance of wrinkles and changes in skin texture.

Collagen production can be stimulated by applying peptides topically. Collagen is not useful in skin care products, since these molecules are too big to penetrate through the stratum corneum (the upper layer of your skin). Short peptides are small enough to penetrate, and when applied topically and in the right ‘carrier’ (i.e. formulation), they can stimulate collagen production. There are different types of cosmetic peptides, each with their mechanism of action. Frequently used peptides in skincare products are signal transduction peptides. When collagen naturally breaks down, the formed endogenous peptides act as an alert system, informing your body to make more collagen. Messenger peptides, such as signal transduction peptides, mimic this natural alarm system, which leads to an increase in collagen production.



Collagen breakdown

Accelerated collagen breakdown can be the result of the wrong lifestyle (sun exposure, stress…) and/or a misprogrammed genetic code. Mutations ( ‘errors’, defects) in MMP genes, such as collagenase (MMP-1) and stromelysin (MMP-3), cause the corresponding enzymes to be ‘overactive’ and to work more rapidly than desired. They break down collagen faster than it is produced. This can cause the skin to lose firmness and age faster. Collagen degradation can be reduced by adding ingredients or active substances to your skincare routine that help reduce the effect of MMP enzymes.





What are the pros and cons of using peptides?

+  Due to their function in helping to reinforce essential proteins in the skin, peptides are powerful anti-ageing ingredients.

+  Different types of peptides can be combined in one cosmetic product: Using different types of peptides results in the activation of different biological pathways. Combining them in one products allows you to have a higher anti-aging effect.

-   Controversy exists over whether peptides are still too large to penetrate you skin barrier (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. If peptides are larger than 500 Daltons, they are probably too large to penetrate. Yet the vector or carrier plays an important role in mediating penetration. The use of certain liposomal formulations aids in effective delivery into the skin. You can read more about liposomal formulations on 'What are liposomes in skincare?'

-   If peptide formulations are not stored correctly, they can be vulnerable to degradation from light and air. Therefore, the packaging of the product is crucial to be effective. In addition, application at night is preferred to avoid degradation effects due to UV light.

-   Some types of peptides can cause irritation for certain skin types.



Choose the right product

The most commonly used (signal) peptide in skincare products is palmitoyl pentapeptide-3 (Matrixyl). It can be found in many skincare products and can be effective in improving the appearance of fine lines. Palmitoyl pentapeptide-3 stimulates new production of type I and II collagen and fibronectin, which are important for the firmness and elasticity of the skin. It is not only important to stimulate collagen production, but also to reduce degradation by inhibiting MMP’s (enzymes that break down collagen). 

Another important tip: do not choose for a peptide-filled product like a face wash, which you will rinse off almost immediately. Polypeptides will be much more beneficial in a cream or serum form, preferably applied at night, as opposed to a cleanser that will be washed off. Your product must also contain a high concentration of peptides to be effective. If you wonder which product you need and which peptides work best for you, have a closer look at your DNA, and you will find out :)