opinions on cosrx aha/bha and numbuzin serum?

The main difference is that the COSRX AHA/BHA Toner claims to use chemical exofliants to help exfoliate the skin. The issue is that the only real chemical exfoliant in it is Glycolic Acid and there's only 0.1% of it. So in reality, it's not gonna do much than hydrate your skin. It does contain Willow Bark Water and Apple Fruit Water in higher concentrations, but let's be real, those won't really do anything for the skin. They also use Betaine Salicylate as well, which is kinda advertised as a gentler BHA alternative, but it's also very low on the ingredient list, probably less than .1%. The Numbuzin No. 3 serum uses different ingredients to back it's claims. It contains fermented ingredients to help gently exfoliate the skin. Ultimately, it really depends on what you want, but I would advise purchasing the COSRX toner as it's basically pointless. If you like fermented ingredients in your skincare the Numbuzin No. 3 Serum is quite popular but it is quite hydrating so if you have oily skin, it might feel heavy on you.