Salicylic Acid in Skincare: The Complete Guide

In K-beauty, salicylic acid usually hides behind three letters — BHA — and you will find it in toners, pads, ampoules and peels. It is an oil-soluble acid, so it gets into the pore instead of staying on the surface, which is why it makes most sense for oily and combination skin, blackheads and midday shine.

What salicylic acid is and why it is called BHA

Salicylic acid is a beta hydroxy acid — hence BHA. Since it is the only acid of that group widely used in skincare, "BHA" and "salicylic acid" work as synonyms in practice: when a Korean product says BHA, it almost always means salicylic acid or one of its derivatives. The key difference from the better-known AHAs (glycolic, lactic): AHAs dissolve in water, salicylic acid dissolves in oil.

How it works on skin and pores

Oil solubility means salicylic acid does not stay on the surface. It travels through sebum and works inside the pore itself — where dead cells mixed with excess oil pile up, making pores look larger and skin texture uneven. The acid loosens the bonds holding those dead cells in place so they detach more easily: texture feels smoother, the T-zone shines less, and blackheads come back to the same spots less often.

Who benefits most

Oily and combination skin, skin prone to blackheads and clogged pores, and anyone bothered by midday shine have the strongest case for trying it. If you are choosing your first product, the natural starting point is the salicylic acid collection; a broader selection by skin type is in the oily skin collection, and thorough cleansing — step one of any acid routine — in the purifying collection. Dry and sensitive skin is not excluded, but it calls for gentler formats and a slower pace.

AHA, BHA or PHA — what is the difference

All three groups remove dead cells, just at different "addresses". AHAs (glycolic, lactic) work on the surface, evening out texture and tone — we cover them in a dedicated guide to glycolic acid and AHAs. BHA gets into pores, which makes it the first pick for blackheads and shine. PHAs have larger molecules, act most superficially and are considered the mildest. Korean brands happily combine them in one product: Some By Mi literally named its toner AHA-BHA-PHA, and Celimax describes its pads as a "BHA + PHA + LHA" complex. The more acids in one product, the more gradually you introduce it.

How to spot it on an INCI list

On an INCI list, look for the name SALICYLIC ACID. That is also how it appears in CosIng, the European register of cosmetic ingredients, whose entry lists functions including keratolytic (softens and helps remove dead cells), anti-seborrheic, skin conditioning and preservative. On Korean ingredient lists you will also meet its relatives: Betaine Salicylate — which CosIng describes as the product of a reaction between betaine and salicylic acid, with antimicrobial and keratolytic functions — and Capryloyl Salicylic Acid. When the box just says "BHA", the INCI list is what tells you which of these forms is actually inside.

Which format to use: toner, pads, ampoule or peel

The same ingredient comes in very different formats, and that is the real buying decision.

A toner is the easiest entry into acids. With Beauty of Joseon Green Plum Refreshing Toner AHA + BHA, both glycolic and salicylic acid appear on the brand's official INCI list, and the brand intends it for both morning and evening. Pads add a light mechanical element and are handy for the T-zone and back: Celimax Ji Woo Gae Cica BHA Blemish Toner Pad contains 0.45% BHA according to the brand; you will find similar formats in the toner pads collection. A leave-on ampoule or serum delivers more concentrated, targeted care — for example Dr.Ceuracle Vegan BHA & Matcha Ampoule. A rinse-off peel is the strongest format and not something for every day. For Heimish RX AHA BHA Peeling Serum the maker declares 21% glycolic and 9% lactic acid; the directions say to leave it on for up to 10 minutes, rinse it off with lukewarm water and use it one or two evenings a week. Heimish also says openly that it is meant for people who already have experience with acids. Related formats are gathered in the peelings and enzyme powders collection.

What the percentage on the label means

European rules offer a useful anchor here. Regulation (EU) 2021/850, amending Annex III of the EU Cosmetics Regulation, caps salicylic acid at 3.0% in rinse-off hair products, 2.0% in other products, and 0.5% in body lotion and colour cosmetics such as mascara and lipstick, and explicitly states it is not to be used in preparations for children under three. In other words, a leave-on face product legally cannot exceed 2% — "the more the better" is simply not on the menu. That is why Korean formulas look modest on paper: Celimax states 0.45% BHA in its pads, and Some By Mi's toner INCI specifies "Salicylic Acid (100 ppm)" — just 0.01%. In practice the difference is made not by the number alone but by the whole formula, the format and how long the product stays on the skin.

How to add it to your routine and how often to use it

Rule one: the format sets the pace, and the brand's instructions are your starting point. Beauty of Joseon intends its toner for morning and night, and advises sensitive skin to try it on a small area first and wait 24 hours. Heimish keeps its peel to one or two uses a week. Rule two: start less often than the label allows — every other evening for leave-on products, for instance — and speed up only once your skin stays calm. Rule three: do not stack several strong acids in one routine, and never skip moisturiser — exfoliation without hydration quickly ends in tight, irritated skin.

Salicylic acid, sun and SPF

Acids and sunshine only mix with protection on top. The warning on Beauty of Joseon's AHA+BHA toner concerns alpha hydroxy acids, the AHA part of that toner: skin may become more sun-sensitive and burn more easily, so the brand recommends sunscreen, protective clothing and limited time in the sun, both while the toner is in your routine and for a week after you stop. That is why anything in this guide comes paired with something from the sun protection collection: morning SPF is part of an acid routine, not an option.

Salicylic acid and niacinamide

These two complement each other well: the acid clears pores while niacinamide works on the barrier and an even tone, and it is not unusual to find both on the same INCI list. If your skin tolerates both, they can share a routine; if it is on the reactive side, keep niacinamide for the morning and the acid for the evening. What niacinamide does and how it is dosed is covered in our separate guide to niacinamide in skincare.

Salicylic acid and retinol

This combination is for advanced users: both ingredients speed up skin renewal and both can be drying, so beginners should not use them the same evening. The safest schedule is alternating nights — acid one evening, retinol the next — with extra hydration and, it goes without saying, SPF every morning. How to introduce retinol from zero and what to expect in the first weeks is in our guide to retinol in skincare.

Purging, mistakes and side effects

When an acid speeds up cell turnover, what was already sitting deep in the pores surfaces faster than usual — so in the first weeks skin can look worse, not better. This temporary flare is called purging, and it typically shows up where you break out anyway. While individual blemishes heal, a practical first aid is the pimple patches collection. If, however, irritation spreads to places where you never break out, or drags on for many weeks, that is no longer purging — take a break. The most common mistakes: using it too often, skipping moisturiser and SPF, and introducing several actives at once. Some By Mi explicitly warns for its toner: if red spots, swelling or itching occur after sun exposure, consult a specialist, and do not apply the product to broken skin.

Salicylic acid for the body

Pores do not stop at the jawline. The back, shoulders and chest carry more oil glands and often react to sweat, clothing friction and workouts — plus there are ingrown hairs after shaving or waxing. BHA does the same job here as on the face: it keeps dead cells from piling up around pores and follicles. Pads are the most practical format for these zones, since they reach the middle of the back. The rules stay the same: introduce gradually, keep it off broken skin, and wear SPF on sun-exposed areas.

Frequently asked questions

Can I use salicylic acid in summer?

Yes — provided SPF every morning, no exceptions. If that is hard to keep up on a beach holiday, it is simpler to save the strong peel for autumn.

Does it dry out the skin?

It can, when used too often or without moisturiser afterwards. The fix is a slower rhythm and hydration after the acid; if tightness persists, step down to a gentler format — a toner instead of a peel, a lower percentage instead of a higher one.

Salicylic acid during pregnancy and breastfeeding?

The most useful answer comes from the maker itself: Beauty of Joseon says plainly that some ingredients in its AHA+BHA toner are not recommended while pregnant or breastfeeding.

When buying, decide in this order: first the format you can use regularly, then the percentage. Start less often than the label allows, and skip neither moisturiser after the acid nor SPF in the morning. If skin looks worse in the first weeks in the places where you break out anyway, that is purging and it passes; if irritation spreads elsewhere, take a break.