Updated May 2019: I’ve added photos at the end for Paula’s Choice C15 Super Booster.
Updated May 2018: I’ve added a photo a 4 month (120 days) photo of the Drunk Elephant C-Firma Day Serum.
Updated April 2018: I’ve added a photo comparing Drunk Elephant’s C-Firma Day Serum that has been opened for 30/60/90 days.
Updated March 2018: I’ve added photos at the end of this post of Drunk Elephant’s C-Firma Day serum that has been open for 2 months.
Updated October 2017: I’ve added photos at the end of this post of Skinceuticals CE Ferulic that was stored in the refrigerator for around 7 months.
I’ve used SkinCeuticals CE Ferulic serum for many years and it would turn darker over time in the bottle. Because I didn’t know any better, I’d use it up until it was gone. Then, I read online that when it changes color and oxidizes you shouldn’t use it on your face. So after throwing out 1/2 of a very expensive bottle, I decided to look for cheaper alternatives.
I read that some folks had very good luck storing their serums in the fridge and taking out smaller quantities at a time to store in their bathrooms for daily use. Refrigerating the serums kept them clear over many many months. After reading that some bloggers had success with Timeless 20% C &E serum and that Timeless guarantees their product to stay fresh for 3 months, I bought it.
After using it for 6 months, I decided to stop using products with alcohol in them (fatty alcohols were the exception). My guess is that the Timeless C&E serum has such a tiny amount of alcohol in it that it doesn’t dry the skin but I wasn’t taking any chances.
I then purchased Cosmetic Skin Solutions Vitamin C & E serum because it is a duplicate for SkinCeuticals CE Ferulic serum in terms of ingredients, although the pH level is higher (although still acidic). And unlike the Timeless serum, it doesn’t include (possibly) drying alcohol as an ingredient. But, I was worried it might oxidize over time even if I kept it in the fridge.
Here are the results…