I don’t like math. I was never good at it, and guess what?! I haven't used a mathematical equation since I left high school. Until now I guess… (this is a hyperbole, of course) I often forget that skincare is a science, and like all science, your very own skincare routine has a formula. If it doesn’t (don’t worry, mine didn’t either until I started researching this), here’s how to problem-solve: don’t mix certain ingredients. Turns out some of the ingredients I’ve been using in my routine actually cancel each other out! By switching out some products and using them on their own on different days, you can get those skin goals and stop wasting product. Now, let’s get to doing some math!
AHAs/BHAs + Vitamin C = 0
Using acids and vitamin C together might sound like a good idea in theory (both promote smooth, bright skin), but let us remind you that vitamin C is also an undercover acid, ascorbic acid. When combined, the acids destabilize and won’t deliver the desired effect (or any effect for that matter–they cancel each other out). So keep your glycolic, salicylic and lactic acids separate from vitamin C in your routine.
Retinol + AHAs/BHAs = Dryness For Days
Acids chemically exfoliate, while retinol promotes cell turnover, both of which are pretty similar concepts, but that’s exactly the reason these ingredients should stay separate. When you over-exfoliate, your skin becomes dry and irritated–not exactly what we want from a routine. Alternate the use of acids and retinol so you can avoid dryness recovery (aka putting moisturizer on every 15 minutes).
Want to see if you've got some ingredients that don't get along well? Go to Rate Your Routine!
Benzoyl Peroxide + Prescription Acne Ointments = You Mad At Your Derm Because Your Prescription Doesn’t Seem To Be Working
While you’d think that both of these would be working overtime to fight acne, this is another combo that just cancels each other out. Benzoyl peroxide will oxidize products like Retin-A and Tretinoin, thus reducing their effects as mighty acne-fighters. If OTC acne products with benzoyl peroxide aren’t cutting it for you, then make the switch to a prescription strength treatment and leave that BP behind.
SPF 15 + SPF 30 = NOT SPF 45
While mixing your SPF may seem like simple math, it’s really not. Adding more SPF won’t actually increase your sun protection. It’s best to add one layer of sunscreen at the very end of your routine in a single layer. Mixing may cause a disruption in coverage!
Oil + Water = No Love
You’ve made it this far in life, so you probably know that oil and water don’t jive. If you’re using a face oil and then a water-based moisturizer on top (or vice versa), it may not sink in as well as you’d hoped. Remember, oil repels water!