Willow Bark Extract
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.
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. 1 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%.
In vitro tests have shown 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, 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.
The choice of preservatives for personal care formulations should be carefully considered. This is especially true when using natural antimicrobials and or other “mild” antimicrobials. We recommend that every formula undergo stability and microbial testing to ensure adequate preservation.
- Aqueous extract
- Naturally derived
- Standardized to an equivalent of 10% Salicylic Acid
- Enhances cell turnover
- Exhibits anti-microbial capabilities
- Offers natural preservation
- Safe, non-irritating and non-sensitizing
- Natural ß-hydroxy acid
INCI: Salix Nigra (Willow) Bark Extract
When using AHAs and BHAs, an appropriate sunscreen should be used and exposure to UVA/UVB rays should be avoided.
Because products formulated with AHAs can increase sun sensitivity, the FDA requires specific labeling of products which contain AHAs and do not include sunscreens. This information and much more is contained in the FDA document USFDA on Labeling for Topically Applied Cosmetics Containing Alpha Hydroxy Acids as Ingredients. The link to this FDA document is also readily accessible in our Reference Room above (please consider it required reading).
Statements contained herein have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat and cure or prevent disease. Always consult with your professional skin care provider.
1 Tsai, J. etal, Distribution of salicylic acid in human stratum corneum following topical application in vivo: a comparison of six different formulations. Int J Pharm 1999 Oct 25; 188(2): 145-153.
California Prop 65 Statement: The following statement is made in order to comply with the California Safe Drinking Water and Toxic Enforcement Act of 1986. This product is not known to the State of California to cause cancer, birth defects or other reproductive harm.
Recommended Usage Level: 2.5-5%, up to 100%
Appearance: Colorless to light amber liquid
Solubility: Soluble in water, glycerine and propylene glycol, immiscible with oils.
Shipping Info: HS# 1302190000
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