Willow bark and aspen bark are both a source of salicin, from which salicylic acid, an aspirin-like substance, is derived. In cosmetics, extracts from these barks are amazing multitaskers that are used for their anti-inflammatory, exfoliating and even preservative properties. Although aspen bark is in our Truth Vitality True Volume Conditioner and Shampoo as well as many skin care formulations, these cosmetic heroes go mostly unsung. So, it is high time to explain just how useful their contribution is — that way, the next time you scan an ingredients list, your eyes won’t glaze over until you see a fancy peptide. Here’s the truth about some of our favorite trees.
Salix, or willow bark, comes from either the black or white willow bark tree. Willow bark is used in many formulas that are trying to avoid harsh chemicals due to its natural content of salicylic acid. Salicylic acid acts as an exfoliant to remove old and dead skin cells (see below for more on salicylic acid).
Willow bark also offers anti-inflammatory properties that can relieve swelling and sensitivity. This makes willow bark ideal for rosacea as well as sensitive blemishes, cystic acne and aging, roughened skin. Willow bark can also minimize age spots and discoloration due to it’s mild exfoliating properties.
Populous tremuloides, or aspen bark extract, is derived from the quaking aspen tree common to northern and western North America. For centuries, Native American Indians have used aspen tree bark for medicinal purposes, from treating burns to reducing fevers to relieving eczema. The bark is rich in salycin, an aspirin-like substance, which is considered to be analgesic, anti-inflammatory, calming and healing.
Aspen bark extract has shown to effectively inhibit the growth of mold, yeast, E. coli, S. aureus, subtilis, and P. aeruginosa. As a natural preservative, it is particularly well behaved. Natural preservatives are sometimes problematic for cosmetic formulators when it comes to consistency, color and odor. Aspen bark does not seem to suffer from these shortcomings, especially if used in formulas that are not water-based.
How Salicylic Acid Acts as an Exfoliator
For aspen and willow trees, salicylates are the defense mechanism that protects the bark from harmful parasites. For us, they are very useful for treating all sorts of skin conditions.
Salicylic acid is in a class of medications called keratolytic agents. Topical salicylic acid treats acne by reducing swelling and redness and unplugging blocked skin pores to allow pimples to shrink. It treats other skin conditions by softening and loosening dry, scaly or thickened skin so that it flakes off or can be removed easily.
As well as helping the skin to be smoother, salicylic acid helps exfoliate the scalp and prevent dandruff (hence its presence in our conditioner and shampoo).
How Willow and Aspen Act as Anti-Inflammatories and Antioxidants
Although it was assumed that the salicin in willow bark was responsible for its anti-inflammatory action, researchers have shown that there are other factors at work, including polyphenols, and since these are antioxidants it means that willow bark is also a free radical scavenger. Other research has demonstrated that willow bark can prevent oxidative stress.
Trembling aspen has also been found to contain antioxidant polyphenols and flavonoids.
Marta Wohrle is an anti-aging skin care and beauty expert and the founder/CEO of Truth In Aging. Marta is dedicated to uncovering the truth behind anti-aging product claims.