Which of your actives can work together?
Pick two to five actives from twelve and the matrix marks every pair as pairs well, fine together or separate, each with a one-line reason. Underneath you get a morning and evening split that keeps the separated pairs apart, and a card you can save.
Which of your actives can share a routine?
Tap what sits on your shelf. Every pair is marked pairs well, fine together or separate, each with a one-line reason, and the split below sorts them into a morning and an evening. Three actives are set as an example, so change them for your own.
Your actives
Retinoid covers retinol, retinal, tretinoin and adapalene. AHA means glycolic or lactic acid, BHA means salicylic acid, and vitamin C here means L-ascorbic acid.
0 of 0pairs work together
The matrix
The matrix scrolls sideways if it does not fit.
Why, pair by pair
A split that keeps them apart
Morning
Evening
How it works.
- Tap two to five actives from the twelve on the list, and swap them as often as you like.
- Read the matrix: every pair is marked pairs well, fine together or separate, with the reason underneath.
- Follow the morning and evening split, and alternate the nights where two evening actives clash.
Three kinds of conflict, and only three
Nearly every pairing warning falls into one of three groups. The first is irritation that adds up: retinoids, hydroxy acids and benzoyl peroxide all speed up turnover or dry the surface, and two of them in one routine double the load on a barrier that needs roughly 14 days to settle. The second is chemical instability: benzoyl peroxide oxidises tretinoin and retinol in the same layer, and ascorbic acid can reduce copper, which is why copper peptides sit better in a separate routine. The third is pH. L-ascorbic acid stays active at 10 to 20 percent and a pH under 3.5, while peptides prefer something close to neutral, so a low pH may break the bonds they rely on. The vitamin C guide has the stability detail, and the acid guide compares glycolic acid at 5 to 10 percent with salicylic acid at 0.5 to 2 percent.
The niacinamide warning is older than the evidence
The idea that niacinamide cancels vitamin C comes from work published in the 1960s, where the two were heated together in unstabilised water solutions and formed a complex that can release nicotinic acid and cause a flush. Cosmetic formulas today are buffered and stabilised, they stay at skin temperature, and the two are sold in one bottle without a problem. Niacinamide at 2 to 5 percent is one of the few actives with no meaningful conflicts at all: it sits beside retinoids, acids and benzoyl peroxide, which is why the matrix marks it green against everything. The niacinamide guide sets out what those 2 to 5 percent do.
What this tool is not
The matrix reads your list against a fixed set of rules. It does not know your formulas, their concentrations or how your skin behaved last week, and strength often decides more than the pairing: adapalene at 0.1 percent behaves differently from tretinoin, and benzoyl peroxide at 2.5 to 5 percent clears spots about as well as 10 percent while drying far less. Separating two actives costs nothing, so when a pair is in doubt, one goes in the morning, one at night, or they take alternate evenings. Add one new product at a time, patch test it on the inner forearm for 3 to 5 days, and give a routine 8 to 12 weeks before you judge it. The retinoid guide explains the strengths. Skin that is painful, weeping or spreading belongs with a dermatologist rather than with a matrix.
Frequently asked.
Can I use a retinoid and vitamin C at all?
Yes, on the same day, in different routines. Vitamin C in the morning under sunscreen and the retinoid at night keeps both at the pH each one likes and halves the irritation, which is why the matrix marks the pair as separate rather than forbidden.
Does niacinamide really cancel vitamin C?
No. The warning goes back to solutions heated together in the 1960s, not to modern buffered formulas. Niacinamide at 2 to 5 percent and a stabilised vitamin C serum can be layered, and many products contain both.
Can AHA and BHA go in one routine?
At low strengths, yes: glycolic acid at 5 to 10 percent with salicylic acid at 0.5 to 2 percent is a common combination. If both are strong, or if your skin stings for longer than a minute, split them across different evenings.
What about benzoyl peroxide with a retinoid?
Benzoyl peroxide oxidises tretinoin and retinol when they sit in the same layer, so the usual answer is benzoyl peroxide in the morning and the retinoid at night. Adapalene is the exception: it stays stable next to benzoyl peroxide, and the two are sold as one product in several countries.
How long should I wait between two layers?
There is no reliable number behind the 30 minute rule you see quoted. Give each layer a minute or two to absorb, layer thin to thick, and use the morning and evening split for the pairs that really do conflict.
Does the tool store what I pick?
No. Your selection stays in the page, nothing is written to your browser storage and nothing is sent anywhere. Reloading the page brings back the three example actives.
Guides behind this tool
Ingredients
Retinol, retinal or tretinoin: strengths, conversion and results
Ingredients
Vitamin C serums: forms, concentration and stability
Ingredients
Niacinamide: what 2 to 5 percent actually does
Ingredients
AHA or BHA: glycolic, lactic and salicylic acid comparedMore tools
The Ingredient Pairing Check compares classes of ingredients against a fixed set of rules. It does not know the concentration, the pH or the rest of a formula, it cannot judge how your skin will react, and it is neither a diagnosis nor a prescription. This page is for general information and does not replace advice from a dermatologist, physician or qualified practitioner.