Peptides are a group of cell-communicating ingredients that are showing up in lots of skin-care products these days. They are tiny portions of proteins, which are made of long chains of amino acids. In the human body, peptides regulate the activity of many systems by interacting with target cells. Enzymes break proteins into peptides so they can exert their influence on systems and get them operating as they should. Some peptides have hormonal activity, others have immune activity; some inhibit growth factors that stimulate scar formation, some play a role in wound healing, and still others affect the pathology of skin conditions such as atopic dermatitis and eczema. Some peptides have demonstrated a remarkable anti-inflammatory effect. Peptides are as abundant and intricate as the stars in the heavens.
Whether peptides have benefit when applied topically to skin for wound healing, skin- barrier repair, or as disinfectants is difficult to ascertain because they generally cannot penetrate skin. At the same time they remain stable because they are too hydrophilic, or water – loving, an ironic fact since peptides can become unstable in water-based formulas (Sources: IFSCC Magazine, July 2004, page 153; and Biotechniques, July 2002, pages 190-192). But details like that have never bothered the cosmetics industry. Whether an ingredient really makes a difference doesn’t enter into marketing or advertising campaigns. All that matters is that the ingredient is new and that the story about it sounds believable.
Further, because peptides are vulnerable to the presence of enzymes, when peptides are absorbed, the abundant enzymes present in skin can break the peptides down to the point where they have no effect at all. However, research is examining how different types of synthesized peptides can remain stable. Creating specific peptide chains in the lab and then attaching a fatty-acid component to them allows peptides to overcome being absorbed and remaining stable, their inherent limitations. Lab-engineered peptides appear to have the kind of efficacy and benefit that go beyond the skin’s surface, but further conclusive, long-term research is essential to gain an understanding of what, if anything, is really taking place (Sources: The Journal of Investigative Dermatology, September 2005, pages 473-481; Cosmetics & Toiletries, June 2004, page 30; and Pharmaceutical Research, March 2004, pages 389-393). It is reasonable to assume that as synthetic peptide technology broadens, we will see more options for use in skin-care products promoting anti-aging properties—and, specifically, tissue regeneration (Source: Cosmetics & Toiletries, March 2003, pages 43-52).
Despite the fact that there is no published research showing that specific peptides in skin-care products can have superior or even improved results when applied topically, that doesn’t stop the cosmetics companies from putting the stuff in their products, claiming, of course, that they can accomplish miraculous feats for skin. There are several of these ingredients but mainly what you will find are copper peptides, palmitoyl pentapeptide-3, acetyl hexapeptide-3, and neuropeptides. None of these have independent supporting evidence that they can perform as claimed, at least not from any source other than the companies selling the products. Often these studies are done with a single comparison, which is meaningless given that there are hundreds of options that could skew the results, if they were studied scientifically. But that isn’t the way cosmetics research is done (Source: InternationalJournal of Cosmetic Science, June 2005, pages 155-160).
For these specialized peptides to exert a benefit beyond that of a water-binding agent, three criteria must be met: the peptides must be stable in their base formula, they must be paired with a carrier that enhances absorption into the skin, and they must be able to reach their target cell groups without breaking down. Oops, I nearly forgot, they must be safe to use! Achieving these goals is no easy feat. Cosmetics companies would love for you to believe they have figured this out, but that is not the case any more than we have a cure for cancer. But this is definitely a promising area in skin care that once developed will have significant potential in the realm of anti-aging skin-care ingredients. For now, peptides have potential benefit as cell-communicating ingredients and most of those used in skin-care products offer value as water-binding agents.
(Sources: Journal of Cosmetic Dermatology, June 2008, pages 143-148; Journal of Cosmetic Science, January-February 2008, pages 59-69; Journal of Investigative Dermatology, May 2005, pages 450-455; New England Journal of Medicine, January 2003, pages 361-363; InternationalJournal of Cosmetic Science, December 2001, pages 207-218; and Proceedings of the National Academy of Sciences, January 2000, 371-376.)