Hi, I'm neither a chemist nor a chemistry student. I'm just a curious reader who likes to know about the science of everyday products.
Basically, I read this paper where it says 5% BPO is more appropriate for wash-off formulations because a 100% reduction of the C. acnes isolates was achieved in 30 s whereas 2.5% needed 15 min.
But, if you look at the numbers, 2.5% BPO achieved 93.4% in 1 minute. And this is why I'd like to know your opinion whether their conclusion is accurate.
I don't think it is really more appropiate for two reasons. But first, let's pretend BPO permors the same in vivo and in vitro, without having the in vivo problems of having to get trough skin pores, etc. The two reasons are:
First, BPO treatments aren't usually taken just one day. They're usually taken for weeks and even months. So I think in 1 month of treatment the reduction of bacteria would not differ much between 2.5% and 5%.
And secondly, the study assumes the active stops working once the product is washed off. But cleansers for example are able to deposit BPO so that it continues working even after rinsing.
The study is this one:
https://pmc.ncbi.nlm.nih.gov/articles/PMC8922035/What do you think?
PS.: I put this in the "other sciences" section because I didn't know if this belongs to biology chemistry (due to the bactericidal effect of BPO) or chemistry engineering (due to wash off formulations being able to deliver actives).