AHA/BHA/PHA

BHA dissolves in oil and works inside the pore, so it is the pick for oily skin and blackheads; the COSRX Salicylic Acid Daily Gentle Cleanser is an easy daily start. AHA works on the surface for rough texture and dullness, and the COSRX AHA 7 Whitehead Power Liquid is made for skin already used to acids. PHA is slower and softer, which is why sensitive skin often starts with the Anua Heartleaf 77 Clear Pad.

For all three acids in one step, the SOME BY MI AHA-BHA-PHA 30 Days Miracle Toner clears dead skin and excess oil and helps skin look clearer, with tea tree in the mix. If you like a mist, the COSRX AHA/BHA Clarifying Treatment Toner exfoliates and hydrates at once. For dull skin that dries out easily, the Beauty of Joseon Green Plum Refreshing Toner: AHA + BHA brings back glow while mung bean hydrates, soothes and supports the moisture barrier.

An acid goes on after cleansing and before serum. Start at two or three evenings a week and build up only while your skin stays comfortable. Mild toners and pads made for daily use can go on every day once you know how your skin takes them; stronger liquids stay on alternate nights. If you notice tightness, stinging or flaking, drop back to one night a week, and always wear sunscreen the following morning.

Yes, just not all at once. Keep vitamin C for the morning and an acid or a retinoid for the evening, and give acid and retinoid nights of their own until your skin has handled each for a few weeks. On acid nights, finish with a plain, hydrating moisturizer rather than another active, and let the next morning's sunscreen do the rest.