I'm working on a lightweight pH 3.5 moisturizer with 1% resveratrol, 3% l-lactic acid and 2% salicylic acid, intended for acneic skin or as a general purpose exfoliating moisturizer. Resveratrol is very happy at low pH and stability has been good enough to give it a 1 year shelf-life, It has some interesting long-term effects vs p.acnes
. Tentative ingredient list:Water, Hamamelis Virginiana (Witch Hazel) Water, 5% Ethyl Alcohol, Rosehip Oil, 3% Lactic Acid, Cetearyl Olivate, Sorbitan Olivate, Glycerin, Sodium Lactate, Caprylic/Capric Triglyceride, Simmondsia Chinensis (Jojoba) Seed Oil, Cetyl Alcohol, 2% Salicylic Acid, 1% Resveratrol (Polygonum cuspidatum) , 1% Camellia Sinensis (Green Tea) Leaf Extract, Sclerotium Gum, 0.3% Allantoin.
(It will undergo USP 51 PET to see if 5% Ethyl Alcohol is adequate as preservative, I don't believe it's significantly drying, but I could be wrong.)
I'm looking for ways to make it more moisturizing and possibly even more effective. What I'm considering adding:
1. ~2% total of Cholesterol, linoleic acid (FFA), palmitic acid and a combination of ceramides (1,2,3,6II) to make it nurture the stratum corneum and provide some occlusion.
2. 1-2% Hydrolyzed jojoba esters (Floraesters K-20W) to give it TEWL reducing barrier properties, according to floratech is has a synergy with glycerin and is potentially a good alternative to silicones.
3. 1-2% Silicones e.g. dimethicone to give it TEWL reducing barrier properties, please advice on specific ones you think would be good in this formula.
4. Petrolatum, urea, other things you suggest.
The formulas would be tested against each other through SLS challenge testing to see which ones prevent TEWL loss applied pre-challenge and accelerate TEWL normalization post-challenge.
Let me know if you have any suggestions, I'm also open to using different emulsification systems if they're low pH compatible and would give it better moisturization properties.