Critique request for an uncommon “cosmetic product”: transdermal hormonal lotion
Due to a lack of accessibility of creams intended for transdermal hormone delivery (Versa Base, and others), I wanted to make my own lotion. I have been messing around with my own lotion formula, and I think I finally ended up on something that’s OK. However, since I know little about lotion making, besides what I’ve learned in the past two months messing around with it, I wanted to ask you guys to critique it and hopefully help me formulate something that’s even better.
Since the goal is to deliver hormones through the skins, my lotion has a few requirements. 1. It has to hold at least 10% hormone. 2. It has to be effective enough at transdermal penetration to be worth using. 3. It has to not have ingredients that are too toxic.
I would argue that my formula is superior to VersaBase, because VB lacks dedicated penetration enhancers besides the emulsifiers. While I have at least three. Propylene glycol and Lauric acid have shown synergism in certain studies for penetration enhancement of certain hormone analogues (much higher LogP, though). And the Nonanol showed an interesting disruption of the cholesterol in the lipid matrix of the stratum corneum.
This is the formula I ended up with so far:
Emulsifiers: Glyceryl Stearate SE - 4%, Eumulgin SG (Sodium stearoyl glutamate) - 1%, Stearyl alcohol - 2%.
Penetration enhancers and solvents: Propylene glycol - 7%, Lauric acid - 7%, and Nonanol - 2%.
Lastly, I am using roughly 10-15% of MCT as a filler oil, 0.5% of Limonene and Eucalyptol each for smell, mild preservative effect, and mild penetration enhancement, and 1% Vitamin E. And obviously, the 10-11% hormone. Also, Geogard ECT for a preservative.
This creates a weirdly watery lotion, despite a massive ~50% oil phase, which is a result of the nonanol and propylene glycol. I added a touch of Stearyl alcohol to help stabilize it, because the nonanol seems to be doing the opposite of that.
Question 1: Is propylene glycol part of the water phase? Since it’s actively solubilizing hormone, does that mean it’s attached to the hormone and therefore part of the oil phase?
Question 2: Is there a way to bump the concentration up to 20% but prevent the waxy skin feel due to the hormone? I managed to make a 20% lotion simply by bumping the Lauric acid and PG up to 10% each, and cutting out the MCT, but the lotion turns out to be rather dry and waxy.
Question 3: Is there any thing else that I should add/remove? Anyone have any advice or comments?