Salicylic Acid (BHA)

What it is

Salicylic acid is a beta hydroxy acid, usually shortened to BHA, used in leave-on exfoliants, cleansers and spot products. It is oil-soluble, which helps explain why it is often chosen for formulas aimed at the look of clogged pores and oily skin. The strength and contact time depend on the product, so a rinse-off cleanser is not the same as a leave-on serum.

Salicylic acid is not the same ingredient as betaine salicylate, although both names include salicylate. Always check the product directions rather than assuming two products with related names should be used in the same way.

What it does

• Exfoliates the surface. It helps loosen dead skin cells at the surface, which can make rough texture look smoother.
• Targets the look of clogged pores. Its oil solubility makes it useful in products for skin prone to visible congestion and blemishes.
• Can help skin look clearer. Regular use may improve the appearance of blackheads and blemishes for some people, but it is not a treatment for a medical skin condition.
• Can cause dryness or irritation. Too much, too often, or use with other strong actives can leave skin tight, flaky or uncomfortable.

Who it suits

Salicylic acid may suit people with oily or combination skin who want an exfoliant aimed at the look of clogged pores. A cleanser may be a gentler way to try it than a leave-on product, although tolerance depends on the whole formula and how you use it. If your skin is dry, reactive or already irritated, begin cautiously or skip exfoliation until it feels settled. Ask a dermatologist about persistent or severe breakouts.

What to pair it with, and what not to

Use one exfoliating product at a time, following its directions. A plain moisturizer can help your routine feel more comfortable, and hyaluronic acid can be an uncomplicated hydrating step. Use sunscreen as directed during the day while using exfoliating acids.

Do not pile salicylic acid on top of glycolic acid, lactic acid, mandelic acid or retinoids when starting out. Over-layering exfoliants can make irritation more likely without making the routine more effective. Add products gradually, patch-test first, and take a break if ongoing stinging, redness or peeling develops.

Skin Realist check: An exfoliant is not a dare. If your face feels tight and cross, the next useful step is usually a break, not a second acid.