Friendly Fridays Q&A: When is the Best Time to Use Each Skin Care Ingredient?
Posted May 27 2011 6:57pm
In honor of relaunching FutureDerm.com this month as a daily beauty blog, I’ve decided to make every Friday “Friendly Friday,” in which I will answer a favorite weekly question from a reader.
This week’s question:
When is it the best time to apply different types of skincare ingredients? I am confused. I’ve been using vitamin C, vitamin E, retinoids, and peptides. Please help!” -Confused
There are two issues at play here. The first is that you want to stagger your ingredients around UV exposure. Some ingredients are best for day, such as antioxidants vitamins C and E, because they boost sunscreen protection. Other ingredients should be reserved for night, like retinoids or alpha hydroxy acids, because they can thin the skin and make it more susceptible to UV damage. A complete list of each kind is shown below.
Ingredients best for day:
Vitamins C and E – In conjunction, can boost UV protection when used under sunscreen. (Ideal concentration: vitamin C 15% or higher; vitamin E 2% or higher).
Argan oil – Argan oil contains a high concentration of vitamin E. As such, it may boost sun protection and protect against oxidative damage as well.
Sunscreen - This should be a “duh!” Michelle Tanner-type moment, but I added it here for the sake of completeness.
Ingredients best for night:
Peptides – Although peptides can also be used during the day (they have not been shown to increase UV sensitivity), peptides also stimulate collagen production, which is a process that takes place over the course of weeks to months in the fibroblasts. To stimulate such a tenuous process, it is best to apply the ingredient at night, when the basal cell temperature is somewhat higher, and the ingredients can penetrate further.
Hydroquinone – Although hydroquinone is used to treat sunspots and irregular pigmentation, it has been associated with onchronosis, a darkening of the skin, in darker-skinned patients. For this reason, some dermatologists recommend using hydroquinone at night, decreasing the chance for UV-induced onchronosis to occur.
It is worth it to note that some skin care formulations are now being produced that are not as susceptible to suboptimal pH levels, due to microencapsulation (ingredients are released somewhat deeper in the skin before release), suspension in different layers of an emulsion (ingredients do not mix), and other techniques. Still, if you are mixing products from different lines or brands, it is best to stick with the time-tested rules, and do not use the following in conjunction:
Retinoids and alpha hydroxy acids or beta hydroxy acids. As previously mentioned, the optimal pH level of retinoids is higher than that of the hydroxy acids, rendering each ingredient to be less effective.
Retinoids and vitamin C. Although you see this combination a lot in drugstore products, again, it’s simply an issue of pH: retinol esterification occurs optimally at a pH of 5.5-6.0, while vitamin C is most active at a pH of approximately 3.0-4.0.
I hope that this answered your question, Confused! If you have a question you’d like to see answered here next week, please feel free to send it to nicki[at]futurederm[dot]com.