The main features of white willow bark extract are the salicylic acid and the salicin, a phenolic glucoside. Salicylic acid, as we saw yesterday, offers keratolytic (exfoliating), anti-fungal, anti-inflammatory, anti-itching, and analgesic properties. Salicin is processed by our body to become salicylic acid, so it is the precursor to all those lovely qualities. We can use white willow bark as a substitute for BHA or salicylic acid in our creations. It is good for oil control products as well.
White willow bark also contains tannins, specifically gallotannins like those found in green tea. This means white willow bark will be a more astringent extract than something like chamomile extract. These tannins have been shown to be excellent anti-oxidants and good anti-inflammatories, offering some post-sun exposure protection and anti-reddening features.
White willow bark extract would be a fabulous inclusion in any products where you want the awesome power of salicylic acid to reduce redness and exfoliate your skin.
As a caution, because it is sloughing off the top layer of your skin, white willow bark and salicylic acid can make you sun sensitive, so you might want to re-consider it in something you might use in the summer. And if someone is allergic to salicylic acid or aspirin, there is a chance they will react adversely to the use of white willow bark. And whatever you do, don't use another extract that offers exfoliation or salicylic acid - there's an example of too much of a good thing!
As a note, you can find powdered white willow bark extract (usage at 0.1 to 1%) or liquid white willow bark extract (2.5% to 5%). Both are soluble in water and should be added to the cool down phase of your product.
Join me tomorrow for some super formulating fun with white willow extract!