I had considered using white willow bark in my acne bars. But I couldnt find usage rates, and their are few companies who carry it. I went with activated charcoal, i found the results to be similar IMO to salicylic acid and it's easier to come by.
Well here's one article http://www.livestrong.com/article/131981-charcoal-soap-acne/ Also there are many posts on the Forum on charcoal. salicylic acid medicated soaps sold in stores, and cp soap with added AC are two totally different animals. My pimple prone friends and family prefer the latter. You'll have to experiment for yourself to determine what's best for you. When I said they are similar I meant in terms of results in finished product. I hope that helps
I know this post is probably late but with Willow Bark extract you can use it at any ratio clear up to 100%. All educational material I have read states that it is safe and been tested at those rates with no adverse reactions, unlike synthetic Salicin.
Just thought this might be helpful for anyone who stumbles upon this post like I did.
I actually use this in my handmade toner with great results in clearing up my acne and excess oily skin problems. Also, I am almost 50 and I have noticed a considerable reduction in wrinkles and increase elasticity. My 27 year old daughter was asking me what I have been using because I have less wrinkles and firmer skin than she does, lol.
I do use AC, tea tree, and clay in my facial bar though and highly recommend that as a facial wash. Use the willow in a leave-on product.