I have been looking into penetration enhancers the last few days. Ingredients like:
- dimethyl isosorbide (DMI)
- tetrahydropiperine (THP)
However, when researching, this thought occurred to me: if you use a penetration enhancer in a formula that contains high molecular weight (HMW) hyaluronic acid, could the penetration enhancer cause the HA to pass through the stratum corneum and go deeper into the skin?
Why it could be a problem:
I find this could be problematic because low molecular weight hyaluronic acid, the kind of HA that can penetrate the skin, has been shown to have an inflammatory effect on the skin. I am wondering if a penetration enhancer could cause a HMW HA to act like a low molecular weight HA if it helps the HA to penetrate the skin instead of just sit on top like it normally would.
I only use HMW HA in my formulas because it thickens the formula, increases spreadability and has a moisturizing benefit.
What do you think? What is your opinion on penetration enhancers in general?