I don't know of any sites, but the BEST way to find ph of products is to buy "ph strips" and take with you shopping. I get my strips from a hobby shop ($3) and do my own testing. It can get very interesting when trying to test at stores before buying -- some places let you, some don't. For those that won't, I test immediately after purchase, like in my car, and if not correct, I take back immediately with the receipt. I test skincare AND hair products regularly when buying for first time.