Part four in my anti-aging series is here and we’re tackling peptides.

You’ll know by now that as the skin ages it loses the ability to keep regenerating cells and this process is one of the most obvious, physical signs of aging. Hence, most anti-aging skincare targets reinvigorating this process. Peptides are no exception and are an essential part of how your body does this naturally, but they have their own limitations.
What are peptides?
They are small proteins that help to make new cells. Quite broad in their determination the easiest way to explain them is by size. Essential, a protein that is fifty amino acids or less is a peptide. They are building blocks that can make up important molecules like collagen, elastin and keratin.
Without them your skin would be less full or ‘bouncy’ and firm.
How do they work?
There has been research on their functionality as a topical skincare ingredient and the consensus is their benefits aren’t definitely known because there isn’t enough data to conclude their functionality.
They likely work topically as they do in the body, as messengers, triggering skin cells to perform specific functions such as building collagen and elastin, encouraging skin to look and act younger.
The problem seems to come from their size. After reading extensively on the subject I’ve come to the understanding that they may too big to properly penetrate the skin. While they may have benefits as a messaging molecule, this function would only be useful if they could penetrate the skin deeply enough to do so.
Their ability to penetrate the skin depends on a variety of factors including; physicochemical properties of the substance (acid dissociation constant [pKa], molecular size, stability, binding affinity, solubility and partition coefficient); the time‐scale of permeation; integrity, thickness and components of the skin, cutaneous metabolism; site, area and duration of application.
There is also scarce information about the factors that effect permeability of peptides and how to produce them at an optimal for penetration, hence many skincare products probably don’t contain peptides that would be able to do so.
Another interesting study by Abdulghani et al. suggested there is little to no anti-aging effects of glycyl‐histidyl‐lysine (GHK)‐Cu (a popular peptide for anti-aging) when compared with Vitamin C. This further supports the idea that skincare products currently available don’t contain peptides that are able to achieve their full potential.
Conclusion
Peptides have great potential and no doubt play an important role when it comes to how your body keeps your skin young. There still needs to be much more research in order to harness their full functionality and so for the time being it would be wiser to invest in other anti-aging treatments.
Sources:
Abdulghani, A.A., Sherr, A., Shirin, S., Solodkina, G., Morales Tapia, E., Wolf, B. et al. Effects of topical creams containing vitamin C, a copper‐binding peptide cream and melatonin compared with tretinoin on the ultrastructure of normal skin. Dis. Manag. Clin. Outcomes 1, 136–141 (1998)