What skincare ingredients can not be used in the same skincare session?Updated a year ago
Some skincare ingredients can inactivate others if they’re used within the same skincare session, so you’ll want to split them up. Here are some examples:
- Benzoyl peroxide can degrade retinoids (with the exception of some optimized prescription formulas). The two ingredients work beautifully to combat blemishes within the same routine, but not one after the other.
- Vitamin C and niacinamide may cause facial flushing if used together, although so far, that hasn’t been an issue with our Vitamin C Superserum and Hydration Cream.
- We already touched on combining low-pH actives with retinoids. You’ll want to split them up or wait for the low pH actives to sink in completely.
Aside from these basics, it’s mostly a question of avoiding irritation. Some experts take a very conservative approach, cautioning against most active ingredient combinations. In reality, there are so many factors as to whether a combination of ingredients will be irritating, including your skin’s level of sensitivity and how the products were formulated.
For example, the Protocol Skincare line is meant to work together pretty synergistically, with a very gentle AHA cleanser that works well in combination with our active leave-on serums.
We also found a lot of incorrect information about certain pairings. For example, some articles suggest that glycolic or salicylic acid will throw off the pH of vitamin C, even though these ingredients are all effective at around the same pH range…
So how do you split up your actives? You have a few options. With products you want to use on a daily basis, it’s easiest to split them across morning and night. Some products, like vitamin C serums, are better in the daytime, others like retinol are better at night, and with most other ingredients, it doesn’t matter, so you can sort it out in whatever way is more convenient for your lifestyle.
If you’re introducing new ingredients or using products that are a little intense for your skin, using them every other day or every two days might work best. That said, we’re not big fans of this approach, since we think it’s better to use products that your skin can happily tolerate on a daily basis, but there are certain scenarios where this might be the best approach.