Ingredient intelligence
Ingredient Conflict Matrix
11 common actives, every pair checked against the same rules as the pairing checker and My Shelf.
The short answer
Few pairs truly clash. Keep retinoids, exfoliating acids and benzoyl peroxide off the same night; split vitamin C and acids across the day. Everything else layers, thinnest first.
Written by Maria Alejandra, founder and editor · Last updated:
Independently researched and reviewed for accuracy. Read our editorial policy or how we research routines.
The full matrix
Every pair, one grid
Tap any square to see the order, the wait and the reason. OK means fine together, Space means same day but apart, Alt means alternate nights.
| Ingredient | Retinol | Vitamin C | Niacinamide | AHA | Salicylic acid | Benzoyl peroxide | Azelaic acid | Hyaluronic acid | Peptides | Copper peptides | Sunscreen |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Retinol | |||||||||||
| Vitamin C | |||||||||||
| Niacinamide | |||||||||||
| AHA | |||||||||||
| Salicylic acid | |||||||||||
| Benzoyl peroxide | |||||||||||
| Azelaic acid | |||||||||||
| Hyaluronic acid | |||||||||||
| Peptides | |||||||||||
| Copper peptides | |||||||||||
| Sunscreen |
Retinol + AHA: Use on alternate nights
Keep them on different nights so your barrier is not doing two jobs at once.
- How to run it
- Exfoliant one night, retinoid another — we would not put them in the same routine.
- Waiting time
- Separate them while building tolerance if using both together causes irritation.
Using a retinoid with an exfoliant can increase dryness or irritation for some people. Separation is a tolerability strategy, not a chemical incompatibility; product directions and clinician-set routines can differ.
Read the full pairing guideIngredient intelligence
Ingredient Conflict Matrix
Tap every active on your shelf. The matrix checks every combination, then re-plans your week so clashing pairs stay apart. Saved products stay on My Shelf.
Your week, sorted
Morning
- Vitamin C
Evening
- Retinol
- Niacinamide
Every combination, checked
Retinol + Vitamin C· Same day, but space them out
Vitamin C in the morning, retinoid at night. No shared wait — they are in different routines.
Read this pairingRetinol + Niacinamide· Fine together
Read this pairingVitamin C + Niacinamide· Fine together
How to read it
These verdicts are about irritation and practical order, not chemistry that cancels products out. Start one active at a time, and follow product labels or your prescriber over any general grid. For two specific products, use the pairing checker; to save what you own, use My Shelf.
References and sources
Evidence reviewed: American Academy of Dermatology; Cosmetic Ingredient Review. Last read in full August 2026 by Maria Alejandra.
Ingredient behavior, tested concentrations, and safety guidance come from the sources below. Which specific product we suggest, the order we put steps in, and how gently we ramp a routine up are our own editorial judgement — useful, but not clinical evidence, and never a substitute for a dermatologist who can see your skin.
- 1.10 skin care secrets for healthier-looking skin — American Academy of Dermatology
- 2.Acne: diagnosis and treatment — American Academy of Dermatology
- 3.Cosmetic ingredient safety assessments — Cosmetic Ingredient Review
