Peptides are very similar to proteins in that both are chains of amino acids. Chains containing fewer than 50 amino acids are considered peptides, while those with more are characterized as proteins. Found naturally in every cell and tissue, peptides play various roles in the body depending upon the amino acids it is comprised of and their sequence on the chain. Some help to regulate bodily functions and processes, while others act like antibiotics to kill bacteria, or as analgesics to reduce pain. In skin care formulations, the three types of synthetic peptides used include single, carrier and neurotransmitter peptides.
Signal peptides stimulate the growth of proteins, including collagen and elastin, which give the skin structure and elasticity. They are also capable of reducing the loss of skin firmness by regulating the enzymes that break down these proteins. The most common signal peptide used in skin care products is palmitoyl pentapeptide-4 (Matrixyl®). Those who wish to improve the firmness and texture of skin while diminishing the signs of fine lines should look for products that feature peptides in this category.
Carrier peptides deliver trace elements needed for wound healing and skin repair processes. An example is copper peptide GHK-Cu, one of the first peptides to be used in skin care formulations. Studies have shown that carrier peptides, like GHK-Cu are beneficial in activating the process of healing and rebuilding skin tissue. This is also called the skin remodeling response. Those who wish to diminish the signs of photodamage, while diminishing fine lines should look for products that feature peptides in this category.
Neurotransmitter peptides, also called neuropeptides, inhibit muscle contraction by blocking the receptors that signal this action. When used in skin care formulations, the intention of neuropeptides is to reduce the appearance of expression lines, such as those found between the eyebrows or around the mouth. Acetyl hexapeptide-3 (Argireline®) is one of the more prevalent neuropeptides used in skin care today.
Because the function of peptides can be as varied as the possible combinations of amino acids, the horizon for peptide researchers is great. For example, peptides are proving beneficial in the treatment of rosacea, eczema, and even hair loss (alopecia).
While the benefits of these peptides certainly sound convincing, they present several challenges to skin care formulators. First, it is difficult for peptides to be absorbed into the skin. Not only do they have a large molecular size, they are also hydrophilic, preventing them from penetrating the skin’s stratum corneum, the cells of which are surrounded by a lipid (fat) barrier. Secondly, the skin contains enzymes, which break down the peptides that are absorbed. In the past decade, researchers have spent a great deal of time modifying synthetic peptides and developing effective delivery systems to overcome these issues. Examples of these solutions include encapsulation, the addition of a fatty acid component to the chain, nanotechnology, and the development of cell-penetrating peptides (CPPs). These challenges point to the importance of using products with proven peptides in their formulation. My best recommendation is to check third party research online before purchasing a product with an active ingredient you have never encountered before.
Peptides are beneficial tools in the fight against the telltale signs of aging. While impressive studies that support their ability to improve the skin do exist, the outcomes are often not in line with consumer expectations. Peptides are by no means a miracle product and anyone who buys a peptide cream expecting to see results in line with the use of Botox® will be disappointed. Actually, I argue that, for some skin concerns, better results may be garnered through the use of retinoids. For those individuals who simply want to take all the steps they can to stave off the effects of aging, the use of peptides is highly beneficial.