Friday, March 30, 2012
Formulating for dry skin: Lower hydration levels
Our natural moisturizing factor contains amino acids (40%), sodium PCA (12%), lactate (12%), urea (7%), ions (18.5%), sugars (like glycerol - 8.5%), and a few other things. We want to draw water to our skin from the atmosphere, so we want to use humectants like sodium lactate, sodium PCA, glycerin, panthenol, honeyquat, and so on in our products.
If you're heard the claim that using glycerin in a dry climate can draw water from your skin, click here to see the research I've done on the topic. My conclusion: Use glycerin with an occlusive ingredient for awesome moisturizing action.
Also think about the stratum corneum lipids found between our skin cells. This is where the lovely linoleic acid containing oils can help our skin's dryness levels.
The water soluble natural moisturizing factor is found inside the corneocytes; the lipid soluble stratum corneum lipids are found outside the corneocytes. (I really recommend reading the series on skin chemistry from start to finish if this interests you!)
1. Live in a more humid climate, or create one with a humidifier. (I'm currently using a lovely one by Sunbeam, a cool mist humidifier that can run for something like 30 hours before it needs refilling. I bought it for about $25 from London Drugs, so it's an affordable one!)
2. Add humectants into your products and add an occlusive ingredient to make sure you trap that water against your skin. And definitely re-apply those products regularly throughout the day.
3. Use only really mild cleansers for our skin and moisturize after cleansing. Ensure our products are pH balanced for skin (for instance, no using really alkaline surfactants like decyl glucoside without modifying the pH) and increase the mildness of those products.
Join me for a little more information about humectants tomorrow before we get into a series of formulating and modifying products for dry skin.
Question: What's the difference between moisturizing and hydrating?
Skin chemistry & types section of the blog
Better crafting through chemistry: Humectants