Serum

they are the same?,maybe the percentages? usually percentages on serum can be higher than toner,lately I’m trying 2 Bha serums and its works great,(this is only my opinion i don’t know the real valid answers 😊)

I think the difference at %, usually in serums more viscous and hight %.

Serums normally have higher concentration of active ingredients but you can get higher concentration BHA/AHA toners too. However there won't be much else in the product. Serums provide a range of beneficial actives and I personally prefer the application. This is my absolute favourite!