They claim that there is no long term effects of using BP, but it hasn't been proven (the worst that is going to happen is wrinkles, and if you only use it for spot treatment then you have nothing to worry about). I've used BP my whole life and i am weening myself off of it now because my skin is starting to get itself under control since I'm getting older. 2.5% is a great choice; many people don't realize that it has the exact same effect as the 10% solution, only it is way more skin friendly and less drying. All Benzoyl Peroxide does is allow the skin to become oxygenated. The P-Acnes bacteria cannot live in oxygenated conditions, and so they die. The BP doesn't actually kill the bacteria itself, rather the oxygen allowed into your skin does the job. Therefore, it seems as though scientists are correct when they estimate that it will cause no long term effects.
Hope this Helps 
It can cause damage but not always and not for everyone.
I used it for 2 years (variety of strengths) without any problems however about 6 months ago I began to get redness and irritation. I stopped using it completely 2 months ago however the redness and irritation remain, despite trying various moisturisers. Still praying for it to go away as a red chin is almost as embarrassing as the inflamed spots I used to get frequently.
Short answer: keep an eye on your skin and follow the advice of the regimen. If your skin becomes red/irritated, cut right back on the amount you use, or maybe even stop.
