A lot of people are confused about what the difference is in these two products. Some think there isn't any difference. This blog post is to help you clear up the differences in these 2 medications.
Salicylic acid is an alpha hydroxy acid (AHA) which means its an exfoliant. I use salicylic acid on cystic acne, which is acne that doesn't have a white head and is more of a painful, red bump. The salicylic acid helps to exfoliate the skin and penetrates the acne more effectively than benzoyl peroxide. As with all AHA's, use a sunscreen when going outside when you are using salicylic acid.
Benzoyl peroxide is a drying agent. I use benzoyl peroxide on acne that has a head (whiteheads) because the benzoyl peroxide actually dries the pimple out and draws the bacteria out of the skin. Sulfur is a drying agent as well. Since some people have both cystic acne and whiteheads, I would suggest using a sulfur based mask to help dry up whiteheads then spot treating your cystic acne with a salicylic acid spot treatment. Slathering both products over your face is a bad idea because it will irritate your skin and may make it breakout worse.
There you have it! Determine what kind of acne you have then pick your weapon. If you have any questions you want answered, don't be afraid to comment!