Sustainable Salicylic Acid - Where does it come from and is it natural?
Natural ingredients are certainly becoming the main focus for many formulators as consumers demand better of their products and the industry as a whole shifts focus to meet the global Sustainable Development Goals. However, not everything has a natural source, so us cosmetic chemists look to ingredients that are naturally derived. Salicylic acid is a very popular ingredient used in both skin and hair care formulations – used to help treat acne, unclog pores, fight inflammation, and could even help with dandruff.[1] It has been used in cosmetic formulations since the turn of the 20th century[2] and for the longest time was synthetically produced. But with new advances in naturally derived ingredients and green chemistry practices, we now have access to a naturally-derived salicylic acid, extracted from wintergreen leaves.
A question that Étymologie customers often pose about their Bakuchiol Rejuvenating Serum, is why the use of “chemical” salicylic acid and not willow bark extract. While it is true that salicylic acid can be synthesized from willow bark as a raw material, willow bark itself does not contain salicylic acid as we know and love it. Salicin was first discovered in white willow bark and first isolated by the chemist Johann Andreas Buchner[3] in 1828. It wasn’t until 1838 when chemist Raffael Piria converted salicylaldehyde to salicylic acid.[4] Salicin is converted to salicylic acid within the gut through a series of enzymatic reactions, so without these enzymes the conversion is not possible and thus will not occur on your face. Therefore, willow bark extract as an active ingredient cannot have the same benefits to the skin that salicylic acid does because it does not contain the beta hydroxy acid. This is where Oil of Wintergreen comes in…
Wintergreen, among other plants, uses methyl salicylate as a defense mechanism against predators. In fact, the essential oil is almost predominantly made up of methyl salicylate and is used in numerous applications like Wint-o-Green Lifesavers! The molecule itself is readily dissolved to salicylic acid under alkaline conditions[5], and this very property is what makes it an effective raw material to manufacture naturally-derived salicylic acid. I’m sure all us formulators would love to have a salicylic acid plant that would give us the chemical as is, but alas there is still some chemistry required. However we can make it kinder to the planet by adhering to the principles of green chemistry – such as using a less hazardous synthesis.
So there you have it – plant-derived salicylic acid picks up the slack where willow bark falls short. Though not directly a natural product, it is still naturally derived fitting the definition since it is coming from a plant. Étymologie believes in safe, ethically and sustainably sourced scientific actives that have a place in skincare and salicylic acid is just that. And with the ethos to create products that are effective and give you results, using willow bark as a stand in for the ever so effective salicylic acid would simply not stand the test.
By Jamie Stanton, @Jamie_the_Chemist
References:
[1] Dancer, Renee Jacques and Rebecca. “Here’s Exactly What Salicylic Acid Does to Your Skin.” Allure, www.allure.com/story/what-does-salicylic-acid-do.
[2] “Methyl Salicylate.” Wikipedia, Wikimedia Foundation, 24 Mar. 2021, en.wikipedia.org/wiki/Methyl_salicylate.
[3] “Salicylic.” Salicylic RSS, www.salicylic.com/2010/08/history-of-salicylic-acid/.
[4] “Salicylic Acid.” Wikipedia, Wikimedia Foundation, 28 Mar. 2021, en.wikipedia.org/wiki/Salicylic_acid.
[5] “Salicylic Acid.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., www.britannica.com/science/salicylic-acid.
