1) is optimal pH of skin care 4,0- 5,0 ? 2) irritating ingredients
Hello, I would like to ask two questions:
1) What do you think about moisturizers with pH 4.0? Is cosmetics with pH 4,0 - 5,0 really better for acid mantle (knowing that skin pH is around 4,7) ?
2) Lately, I found some evidence that essential oils and their particles found in many other ingredients like flower waters, CO2 extracts, menthol, camphor are not only allergens, but might have irritating potential as well. Are you aware of some evidence based source where I can check if the ingredient is irritating?Thank you very much!