Active Ingredients
At Peak Efficacy
Active ingredients are quite fragile and oxidize and degrade rapidly, even more so when repeatedly exposed to light, air, and touch. This is visible in Vitamin C solution which changes color from clear to brown over time. But it happens with many active ingredients - like vitamins, antioxidants, retinol, acids, and even oils - so much so that studies have shown the average skin care loses half its ingredient efficacy in just a few months! Not only are degraded ingredients ineffective, but some may also lead to skin sensitivity and irritation.
