BHA Blackhead Power Liquid 4%.

"I actually really like this product. The first ingredient is Salix Alba bark water, which is a great anti-inflammatory. It has great moisturizers in it too, so it's got butylene glycol, panthenol, and arginine. Butylene glycol is quite good because it's a solvent but it also helps the other ingredients penetrate deeper into the skin. [...] It has 4% salicylate betaine. In Korea, they're not actually allowed to put in high percentages of salicylic acid, so what they do is they combine betaine, which is a moisturizer, with salicylic acid. The combination of 4% of this is similar efficacy to 2% salicylic acid. The fourth ingredient is niacinamide, which is one of my favorite ingredients and it's great for skin of color. It [...] helps to reduce hyperpigmentation and helps to reduce your sebum levels."

"The active ingredient in this one is betaine salicylate, not salicylic acid. They're two completely different molecules. Betaine salicylate is derived from salicylic acid and from sugar beet, and it's a gentler, milder form of BHA. It's listed as 4% BHA, but you need roughly double the concentration of betaine salicylate to get a similar effect to salicylic acid, so 4% betaine salicylate is equivalent to about 2% salicylic acid in exfoliation strength. The marketing is technically accurate, it does contain 4% BHA, but it's not the same BHA, and the way it's marketed makes it easy to assume you're comparing the same molecule at different price points when you're not. This one is for you if you're newer to chemical exfoliants, your skin gets reactive or sensitive easily, you've tried BHAs before and found them too harsh, or you want something you can work up to using more regularly without the intensity of a true salicylic acid. It also has niacinamide and sodium hyaluronate built in for hydration and barrier support alongside the exfoliation, which is a genuinely smart formula decision, especially for anyone whose skin leans dry or combination. Price per use, it actually stretches further because you use less product per application and the bottle lasts longer, so if budget matters and your skin leans sensitive, this isn't a compromise option, it's genuinely the smarter buy for your skin type. It's also a safer choice if you're allergic to aspirin."

"This is the BHA blackhead power liquid and I was really surprised by this one. It has four percent betaine salicylate, which is the gentler ingredient they're calling BHA now, not the same as salicylic acid. If you have more reactive or acne prone reactive skin like me this might actually be a really good option. It has a little more body to it than a lot of COSRX's watery toners, which makes it easier to work with, you don't need a cotton pad. It also has willow bark in it, which has anti inflammatory properties rather than being an exfoliant like salicylic acid. It's gentle and straightforward, and gentle can be the perfect fit."

"Like a lot of other Korean BHA products, this uses B10 salicylate because of regulations around salicylic acid, but it does just split up into salicylic acid and betaine once there's water around. This also has willow bark water, which is a natural source of salicin that gets converted into salicylic acid, and it has niacinamide, which is a really trendy ingredient. I personally didn't see much of a difference when I used this, probably because I use so much Paula's Choice two percent BHA. In general, I would recommend getting chemical exfoliants from Western brands because it is one of the categories that is really lacking in Asian skincare. I think this could be an option if you find Western products a bit too harsh, so I'm probably going to put this in meh."