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.
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hehehhehe.. people are so funny…
I’d never heard of the Hayflick Limit until now. Thanks for clarifying that.
Whew. Thanks Beauty Brains! Now I can exfoliate (conservatively) with peace of mind…
Good information. You never disappoint!
sorry to be a nerd, but it’s called telomere, not telemere. keep up the great work!
Thanks, Beauty Brains, for tackling the causes of aging! We spend so much money on anti-aging products without really knowing much about aging.
About the Hayflick limit. . . the cellular aging community recognizes that it is actually a LOT more complicated than telomeres. While it is true that cells “senesce” or stop proliferating at some point, it is not a set number, but a range of about 50 to 70. Further, the causes of cellular senescence are still being evaluated; the telomere shortening theory is just one component of what is proving to be a VERY complicated puzzle. There are so many theories as to why and how our cells age. The actual mechanism of aging is probably a combination of these ideas. Cellular aging applies to more than just having gorgeous skin throughout our lives, though. It has also made contributions to our understanding of diseases that strike — or change in some way — as we get older like heart disease, cancer, liver disease, diminished immune function, and on and on.
Just to put in a plug, though, make sunscreen part of your routine. Even if cancer doesn’t scare you, cells in culture senesce rather rapidly when exposed to UV. Before you spend $100 on a cream with the water from the fountain of youth, invest in sunscreen. That’s a much bigger worry for skin, young and old, than over-exfoliating.
Anyway, as this is my first post I gotta say thanks again for your so cool website. You’re awesome.
i have never heard of the hayflick limit but I am a licensed esthetician and you CAN definately exfoliate too much. there is a top layer of your skin for a reason. of course if you have dry skin or are trying to get rid of any impurities clogged in your pores its great to help your skin out with its natural exfoliation process. but we are taught in school that you shouldnt exfoliate more than once a week. doing more thins out your skin, causes irritation, is VERY prone to burning even in the winter sun. remember too much of anything in excess is not good
Thanks for the correction Vic. Some lobes of this Beauty Brain didn’t take as much biochemistry as others.
Thanks for the added information A Pena and welcome to the Beauty Brains. We hope you comment often.
the only issue i have found with too much exfoliation, is that it can dry out the skin, thus not letting your pores accumulate enough oil to flush out anything bad…which leads to blackheads.
Hi Left Brain,
Your reply and all the comments refer to exfolition. But no one picked up on the retin-a part of the question. Retinoic acid (tretinoids) as I understand it do not cause exfoliation but repair photodamage at the deeper levels of the skin. The National Science Foundation says that this form of drug (also used in cancer treatments) inhibits telomerase and leads to telomere shortening. That sounds like it would speed skin aging. Since I use retin-a for acne and it works great fr me (I’m inmy 40s) I am now pretty concerned.
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