Skincare ingredient conflict checker
Choose the active ingredients in your routine. The checker shows every pair, which ones clash, which are fine together, and why, then suggests how to split them between morning and night. The verdicts follow drug labels and published research, not internet folklore.
FreeNo sign-upNothing is saved
Tap the actives you use (pick two or more)
Popular pairings
- Niacinamide + Salicylic acidFine together
- Retinol + Vitamin CSplit AM / PM
- Glycolic acid + Salicylic acidUse with caution
- Retinol + Glycolic acidDon’t layer
- Adapalene + Salicylic acidUse with caution
- Salicylic acid + Vitamin CSplit AM / PM
- Vitamin C + Azelaic acidFine together
- Vitamin C + Glycolic acidSplit AM / PM
- Niacinamide + Hyaluronic acidFine together
- Niacinamide + RetinolFine together
- Retinol + Salicylic acidUse with caution
- Retinol + AdapaleneDon’t layer
How this tool works
- Each pair of actives has a verdict: fine together, split between morning and night, use with caution, or don’t layer.
- Verdicts with hard evidence cite it, such as benzoyl peroxide degrading tretinoin in light, and the FDA-required warning about using two topical acne medicines at once.
- The routine plan puts antioxidants in the morning, retinoids at night, and exfoliating acids on retinoid-free nights.
- Nothing you select is saved or sent.
Sources: Martin et al., Br J Dermatol 1998; FDA acne drug labeling, 21 CFR 333.350; Differin gel prescribing information; AAD: acne treatment tips; Healthline (dermatologist-reviewed): niacinamide and vitamin C
Frequently asked questions
Which skincare ingredients should not be mixed?
The pairings with the clearest evidence against layering are tretinoin with benzoyl peroxide, and retinoids with exfoliating acids in the same routine. Several others are better split between morning and night. Niacinamide and hyaluronic acid pair with almost everything.
Can I use retinol and vitamin C together?
Yes, but most people do better with vitamin C in the morning and retinol at night. There is no proven reaction between them; splitting them simply lowers irritation.
Can I use niacinamide and vitamin C together?
Yes. The idea that they cancel each other out comes from old experiments that heated the pure ingredients together. At room temperature in normal products, they are fine to layer.
Can I use benzoyl peroxide and adapalene together?
Yes. Adapalene stays stable with benzoyl peroxide, and the two are sold combined in one product. Watch for dryness and cut back if your skin gets irritated.
Do this automatically in the app
Acnera is a skincare ingredient checker and scanner for iPhone. Scan a product to see if it suits your skin, and check your whole routine for ingredient conflicts.
How Acnera checks this for you