How often should I exfoliate with acids?

Most skin types do well with chemical exfoliation two to three times per week. Over-exfoliating is a common mistake that leads to a compromised skin barrier, redness, and sensitivity. If you are using a strong acid like glycolic at 10% or higher, start with once weekly and build up. Sensitive skin may do best with just once or twice a week using a gentler PHA or low-percentage lactic acid.