Kelly’s question: Hi! I recently read something about the “Hayflick Limit” – but in relation to exfoliating and using products like Retin-A that says you can only exfoliate a finite number of times and then your skin will stop reproducing new cells! Is this true? I’ve just started a regimen of AHAs and Retin-A and my skin looks gorgeous. Am I setting myself up for the “Hayflick Limit” if I use these products once a day?
The Left Brain’s Limited Reply:
The Hayflick limit determines the life span of some types of cells. When cells replicate they lose a little piece from the end of their DNA chain, which is called a telomere. Eventually the telomere becomes so short the cell can no longer reproduce. In a cell culture, normal human cells will divide 52 times before they reach their Hayflick limit. (For a more detailed discussion of the Hayflick limit and exfoliation, check out this thread from Smart Skin Care.)
What does this have to do with exfoliation? Apparently not very much. When you exfoliate you’re stripping off the top, dead layers of your skin (the stratum corneum) which triggers the deeper basal layer to produce fresh cells. I couldn’t find any references that indicated that telomere shortening of the basal layer is a consequence of exfoliation. This sounds like another marketing scam to me, so be very wary of products like Dr. Tolonen’s Bio-Carnosin Beauty Cream, that claim to reduce the Hayflick limit through the use of Carnosine.
Of course, there are other issues to worry about. Exfoliation can cause irritation, so you should still be careful how much skin you strip away.