Can I use these together?
Pick the products on your shelf and we'll check every combination for clashes — retinoids fighting acids, benzoyl peroxide killing your vitamin C — then build you a morning and evening order that actually works.
Every combination, checked
Pair-by-pair analysisYour routine, in order
Built from what you pickedAdd at least two products above and the analysis appears instantly. Nothing is uploaded — it all runs in your browser.
Your selected routine — saved on this device, and to your free account when you're signed in. See or clear it in My Library.
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How the checker works
Every product in the DermApproved database carries a normalized map of its active ingredients — retinoids, AHAs, BHAs, vitamin C in its pure and derivative forms, benzoyl peroxide, copper peptides and more — extracted from its full INCI list. When you select products, the checker runs every possible pair through a dermatology-standard interaction matrix and flags what clashes, what needs spacing out, and what genuinely works better together.
It then assembles your products into a morning and evening routine using the thin-to-thick layering rule, automatically pushing retinoids to the evening, pure vitamin C to the morning, and marking combinations that belong on alternating nights.
Common questions
Can I use niacinamide with vitamin C?
Yes — the old warning comes from a 1960s study on unstabilized ingredients at high heat. Modern formulas coexist happily, and the combination is actually complementary: vitamin C brightens while niacinamide calms and supports the barrier.
Can I use retinol and exfoliating acids together?
Not in the same routine, for most people. Both increase cell turnover, and stacking them multiplies irritation without multiplying results. The standard fix is alternating nights — acids on Monday, retinol on Tuesday — or acids in the morning if your skin tolerates it.
Why does benzoyl peroxide clash with vitamin C?
Benzoyl peroxide is an oxidizer, and L-ascorbic acid is exquisitely oxidation-sensitive — applied together, the benzoyl peroxide can degrade the vitamin C before it does anything useful. Use vitamin C in the morning and benzoyl peroxide at night, or on alternate days.
What order should I apply my products in?
The general rule is thinnest to thickest: cleanser, toner, treatments and serums, moisturizer, then sunscreen in the morning or occlusives at night. This tool builds that order automatically for the products you select.
Where does the interaction data come from?
Each product in our database carries a normalized list of its active ingredient classes, derived from its full INCI list. The checker runs every pair of your products through a dermatology-standard interaction matrix — the same rules dermatologists use when they tell you to split actives between morning and evening.