Does exfoliation make you run out of skin faster? Plus:  Beauty Science or Bull Sh*t Round 2: Randy quizzes my beauty science knowledge again. 

Show notes

Beauty Science or Bull Sh*t

This is the game where Randy gives me 3 beauty science news stories and I have to tell the real from the fake. You can play along at home - just hit the pause button before we give the answer. Here are this week's headlines, can you tell which one is TRUE?

1. Bacteria-filled liquid crystals could supplement the skin's natural defense system.

2. Shampoo ads that ask you to imagine the smell of the product are more compelling.

3. Beautiful people have fewer pathogenic nasal bacteria.

Question of the week: Does exfoliating make you run out of skin?

Melanie asks…"I've read that there is a limited number of times a person should exfoliate due to the Hayflick limit.  Is that true?"

What is exfoliation?

Exfoliation is the process of removing excess dead cells which causes your skin to increase production of new cells. This is technically known as “increasing cell turnover.” Benefits of exfoliation include facial rejuvenation, acne control or prevention of precancerous growths.

Methods of exfoliation

“Regular” face washing

AHAs

Retinoids

Chemical peels (glycol acid, TCA)

Dermabrasion

What is the Hayflick limit?

It’s a property of cells discovered by Leonard Hayflick in 1961. He found that there is a limit to the number of times a fully differentiated human cell divides. These cells can only divide about 50 times and then they die. This happens because 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. So does this mean that exfoliating causes our new cells to be used up faster? Will we eventually run out of skin? The answer lies in the TYPE of cell.

Two types of cells

Stem cells are undifferentiated (or unspecialized) cells which means they can reproduce in two ways: they can make more stem cells or they can differentiated cells. (Potential future form)

Differentiated cells change size, shape, and metabolism to perform a specialized task. (Final, useful form)

Which type are skin cells?

Actually they’re both. The deepest layer of the epidermis is called the stratum basale which consists of basal keratinocyte cells. These are epidermal stem cells. They divide to form two types of cells: keratinocytes (which are “regular” skin cells) or more stem cells.

The keratinocytes die and are sloughed off and are replaced by new cells about every 35 days. So in other words, your skin is replaced about 10 times per year.

So why don’t we run out of skin cells?

The Hayflick limit only applies to fully differentiated cells. (In this case the keratinocytes.) Stem cells are NOT fully differentiated so they can continue to reproduce without any limit.

Here’s common sense proof: If the Hayflick limit applied then…

ANYTHING that scrapes of skin would use up your cells (not just exfoliating): Taking a bath, shaving your face - or your legs - or whatever you shave.

Skin scratches and cuts would stop healing at some point.

Criminals could just sand away their finger prints and they wouldn’t grow back.

None of these things happen because the Hayflick limit doesn’t apply to epidermal stem cells.

The Beauty Brains bottom line

The Hayflick limit doesn’t apply to the type of cells that make new skin cells. So you can never run out of skin by exfoliating. In fact, exfoliating provides health and beauty benefits so it’s something that you should do regularly.

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