Guide
What is the difference between physical and chemical exfoliation, and how much is too much?
Physical exfoliation uses a scrub, brush, pad or sponge, while chemical exfoliation uses acids such as AHAs and BHAs to dissolve dead skin cells. Gentle and infrequent is the safer pattern, because over-exfoliating can leave skin red and irritated.
Two ways to lift dead cells
Exfoliation removes dead cells from the outer layer of skin, and the American Academy of Dermatology notes it is not for everyone. Mechanical methods use a brush, pad, sponge or scrub. Chemical methods use acids: the US FDA names glycolic and lactic acid as the most common AHAs, and salicylic acid as the most common BHA in cosmetics.
How often and how hard
The more aggressive the method, the less often it should be used. Apply a scrub or acid gently in small circles for about 30 seconds, rinse with lukewarm water, then moisturize, since exfoliating can be drying. Skip broken or sunburned skin. Harsh exfoliation can leave dark spots for some people, especially with darker skin tones, and adding it on top of retinol can worsen dryness.
Acids and the sun
Studies cited by the US FDA found that AHAs made skin more sensitive to UV, an effect that faded about a week after stopping. The FDA recommends sunscreen, protective clothing and less time in the sun while using AHA products and for a week afterward, and sun protection with BHA products too. If redness or irritation persists, stop and see a dermatologist.
Try this
- Use one exfoliating method at a time, and start infrequently.
- Work gently, rinse with lukewarm water, then moisturize.
- Wear sunscreen daily while using acids, and for a week after stopping AHAs.
A common mistake
Exfoliating harder or more often to hurry things along, which can leave skin red and irritated.