How Long Does a Damaged Skin Barrier Take to Come Back?

Barrier function that has been knocked down once comes back largely within days, but the whole surface of the skin takes weeks to turn over. Rather than adding products to speed things up, cut back first on whatever keeps breaking the barrier down. You'll often hear that skin renews itself every 28 days. The timeline only makes sense once you split it into two processes that run at different speeds.

How many days does barrier function take to come back?

Barrier function returns faster than most people expect. When the barrier is disrupted, the skin is understood to make new cholesterol, fatty acids and ceramides, and to release stored lipids that fill the gaps in the outer layer (Feingold, 2009). How wide those gaps are is measured as transepidermal water loss (TEWL) (Kottner et al., 2013). In young skin, barrier function was back about 50% at 24 hours and about 80% at 72 hours. (Ghadially et al., 1995) What the study measured was barrier function, not the day tightness or stinging goes away. And because the barrier was disrupted only once, it's hard to assume the same pace for skin that keeps getting stressed.

How long does the surface take to turn over?

A new surface takes far longer than barrier function. Count one full turn as a cell rising from the base of the epidermis to the outer layer and shedding, and the figure you usually hear is 28 days. One full turnover of the epidermis takes about 47 to 48 days. That figure is a calculated estimate (Iizuka, 1994). So roughened texture won't turn smooth in a few days. If the texture doesn't change right away, it can help to keep the stress low rather than switching products.

Why does it take longer for some people?

Two big things slow the process: age and repeated stress. In people over 80, barrier function came back only about 15% at 24 hours, then lagged further over the next six days (Ghadially et al., 1995). Older skin is known to make lipids, cholesterol in particular, more slowly (Zettersten et al., 1997). A strong cleanser can break down a barrier that is still coming back. Cleansers can wash away protein and lipid from the outer layer along with the dirt (Ananthapadmanabhan et al., 2004). Exfoliants are often cut back for the same reason, but we couldn't find a study that measured how they change the timeline.

Can a moisturizer help the barrier come back faster?

A lipid mix with three times as much cholesterol as each of the other lipids brought the barrier back faster in older skin. (Zettersten et al., 1997) These were research mixes, so the same result hasn't been shown for store-bought moisturizers or for younger skin. For how niacinamide and panthenol support the skin's own lipid production, see Niacinamide and Panthenol for the Skin Barrier: Why Use Them Together?

In short: the barrier comes back on two clocks, days and weeks

A disrupted barrier first refills its lipids and regains function; replacing the cells takes much longer after that. One full turnover of the epidermis works out to 47 to 48 days (Iizuka, 1994). You can't change your age, but you can cut down the stress that keeps coming in. When your skin feels tight and stings, hold off on new products and cut back on cleansing and exfoliation first. Switching products often while the skin settles makes it hard to tell which one is the irritant.

What you can try today

• Starting today, pause either your strongest cleanser or your exfoliant. Cleansers can wash protein and lipid out of the outer layer (Ananthapadmanabhan et al., 2004). Right after washing, compare whether tightness and stinging feel milder than before. If the skin weeps, cracks, or the redness spreads, see a dermatologist. To decide what to drop first, see Why You Don't Need a 10-Step Routine.
• Check that your moisturizer's ingredient list has ceramides, cholesterol and fatty acids together. In older skin, a lipid mix higher in cholesterol brought the barrier back faster (Zettersten et al., 1997). If it doesn't sting right after you apply it, keep using it. If it stings or turns red every time, stop that product. For the ceramide names on the label, see Ceramide NP, AP, and EOP: What the Letters Mean.