Black willow bark Extract is used in natural skin care products for its astringent, antiseptic, anti-inflammatory and antipyretic properties. Willow Bark Extract is a source of natural salicylic acid-like ingredients.
which has been shown to contribute effects similar to those seen from synthetic salicylic acid with none of the drawbacks associated with its use, primarily irritation. As such, it is a safe way to get the benefits of a ß-hydroxy acid.
Salicylic acid, when used in cosmetic formulations at 0.5% to 1%, enhances skin cell turnover by promoting exfoliation, resulting in a general improvement in the appearance of the skin and a smoothing effect with accompanying reduction of fine lines and wrinkles. Also known for its antimicrobial properties, it can be useful as a remedy for problem skin conditions.
The superior exfoliation action of Salicylic acid is thought to be a result of its lipid solubility. Concentrating its exfoliation action in the lipid-rich outer layers of the skin, where the natural rate of exfoliation reduces with aging, it helps to reduce the buildup of dry, dull skin flakes. Willow Bark Extract has been found to be non-irritating to the skin, even at a level of 100%, equivalent to 10% synthetic salicylic acid. Willow Bark Extract has been found to increase stratum corneum turnover more so than salicylic acid – 24% as opposed to 22%.
The Willow tree, of the family Salicaceae and genus Salix, is common to much of North America. The Black Willow (Salix nigra) tree, famous for its dark brown, ridged bark which is rich in tannins and salicylic acid-like materials, is found primarily in the eastern part of the continent. Aqueous extracts of the bark made from freshly harvested bark collected in the spring are said to have analgesic, antiseptic, astringent, anti-pyretic, and anti-inflammatory properties.
In vitro tests have shown black Willow Bark Extract to have activity against Staphylococcus aureus and Propionibacterium acnes, the two strains of bacteria implicated in the formation of acne, as such it may prove useful in targeted facial cleaners, toners and lotion formulas.
In addition, challenge testing has shown that, in cosmetic formulations, of varying degrees of complexity, black Willow Bark Extract, when present in concentrations of 2.5 – 5%, contributes to the preservative efficacy of formulas even when no other synthetic chemical preservatives are used. It has proven efficacy against gram positive, gram negative bacteria, yeast, and mold.