If you are choosing an exfoliating product for rough surface texture, an AHA is one category to consider. If clogged pores and blackheads are the main concern, salicylic acid, commonly called a BHA in skincare, is a useful ingredient to recognise. You do not need one of each simply because they appear together in Korean product names.
The finished product matters more than a race for the largest percentage. The acid used, its concentration, the formula and how long it stays on the skin all affect the routine. A low-strength toner, a rinse-off cleanser and a strong peel are not interchangeable ways of using the same label.
What the names tell you
AHA stands for alpha hydroxy acid. Glycolic and lactic acid are familiar examples, with other acids also belonging to the group. They are used in exfoliating formulas to help improve the feel and appearance of uneven surface texture.
BHA stands for beta hydroxy acid. Salicylic acid is the familiar example in acne skincare. The AAD's adult-acne guidance describes its role in exfoliation and unclogging pores, particularly for whiteheads and blackheads. That is more specific than treating every blemish as the same problem.
Some Korean products use related ingredients such as betaine salicylate. COSRX's Korean A-sol listing, for instance, identifies that ingredient alongside lactic acid. Do not assume the same stated percentage of two different ingredients means an identical product or the same use instructions.
Match the choice to one main concern
For a rough, uneven surface, compare a suitable AHA product and how it is intended to be used. For persistent pore clogging, salicylic acid is a clearer starting point to investigate than another product chosen only for its glow claim.
Neither category obliges you to exfoliate. If your skin is already comfortable and the texture does not bother you, you do not need to find a problem for an acid to solve. If it is sore, flaky and irritated, adding an exfoliant may be the wrong response to the rough feel.
For painful, persistent or scarring acne, a cosmetic acid comparison is not a complete treatment plan. Get appropriate advice rather than repeatedly increasing the strength of a toner because the first one did not fix every type of spot.
Why the percentage is not enough
COSRX's ingredient guidance notes that concentration, product pH and formulation can change the directions. That is why an acid name on the front cannot tell you whether to rinse it off, leave it on or use it as often as another product.
I look at ingredient lists when buying skincare, but I often have to look the names up again because I have forgotten what they do. For acids, I find it more useful to come back to a few practical questions than to memorise the entire label.
Check those practical details before buying. Is it a cleanser, toner, serum or peel? Does it need rinsing? What application and frequency does the label specify? A product you can use comfortably and consistently is a better choice than a much stronger one you cannot fit into the routine.
Do not compare a multi-acid blend's headline number with a single-acid product as though the figures measure exactly the same thing. More acid names on the box do not establish that it is more suitable for your skin.
Consider the rest of the week
An exfoliating toner is not the only product in the bathroom that can affect tolerance. The AAD's safe-exfoliation advice specifically flags products such as retinol and prescription retinoids when considering irritation from exfoliating.
If you already use retinol, first work out which nights you use it and whether your skin is comfortable. Adding several new active products together makes it difficult to know which change caused a problem. Introduce one change at a time within the product's directions, keep moisturising care straightforward and maintain appropriate sun protection.
A stinging sensation is not a target to chase. Nor is visible peeling proof that a routine is improving. If a product leaves you persistently uncomfortable, stop and reassess rather than using another layer to force a faster result.
What I would buy first
Choose one product for one clear concern, with directions you are willing to follow. For surface texture, compare suitable AHA formulas. For blackheads and clogged pores, look at salicylic acid options. If irritation is already the main issue, leave exfoliation out while you address that.
Before paying, check that the product addresses your main concern and that you understand whether to rinse it off and how often to use it. Those details matter more than choosing the largest percentage.