It last for a very long time. You just add a dab on top of each blemish or pimple and even on top of black/white heads. The Benzol Peroxide goes to work immediately. It dries out the pore and destroys acne causing bacteria. It is the strongest without a script, and yes it is strong. Test to see how much your skin can handle as it can cause irritation if overused.. sometimes less is more right?. Also, Benzol Peroxide can cause a "bleaching" effect. Your skin doesn't go white, your clothing can. I find also Benzol Peroxide is a way better choice for fighting tough blemishes than salicylic acid. Neutrogena has other ingredients formulated in this bottle to help combat the harshness of the benzol peroxide so it is for all skin types. I recommend this product.
These reviews are the subjective opinions of ChickAdvisor members and not of ChickAdvisor Inc.