Can I use these together?
Retinol and vitamin C in the same routine? An acid toner on top of a retinol night? These questions come up constantly, and the answers online contradict each other. This tool gives you the verdict from our ingredient pairing research, plus what to do when two things need separating.
Pick two ingredients and the answer appears here. Copy the page address to share the result.
The four answers, and what they mean
| Answer | What it means |
|---|---|
| Recommended | Better together than apart. One does a job, the other supports it |
| Fine together | No reason to keep them apart |
| With conditions | Workable if you meet one condition, usually a time or frequency split |
| Take care | Irritation stacks, or one interferes with the other. Usually solved by splitting them across the day or the week |
Take care is not a ban. Most of the time it means don't apply both on the same night. Move one to the morning, or run them on alternating days, and the pair works. The tip on each card is that split.
Where these answers come from
Each result card says which of two sources it used. If it points to an article, we wrote about that specific pair and you can read the full reasoning. If it says the answer came from general principles, no dedicated article exists yet, so the tool applied the three rules our pairing articles established: ingredients with an irritation profile should not stack in one routine, gentle ingredients can go anywhere, and sunscreen belongs with all of them. For two gentle ingredients there is no more precise answer than that, so a principle-based reply is the complete one. When two actives meet and we have no article yet, the tool leans toward the cautious side.
Where the four answers came from
The vocabulary is fixed across this site rather than invented per question. Recommended means the pair is better together than apart. Fine together means there is no reason to separate them. With conditions means one condition, usually a timing split, makes it work. Take care means irritation stacks or one interferes with the other.
Holding to four words matters more than it sounds. Pairing advice online drifts between avoid, be careful, some say, and it depends, and none of those can be compared across two sources. A fixed vocabulary lets you compare our answer for one pair against our answer for another.
Hangul and INCI in the same result
Every ingredient in the dictionary carries both its Korean standard name and its INCI name, so pasting either produces the same reading. The result card shows the INCI name with the Korean name beside it, which turns any reading into a small bilingual reference.
That is useful in a specific situation: comparing a product bought inside Korea against the export version of the same product. Paste both lists, compare the marked-up results, and you can see whether the formula actually changed or only the language on the box did.
What this tool does not do
It does not rate products or tell you what to buy. It describes how two ingredients behave in general, which is different from how a specific product will behave on your skin. Concentration, formula and your own tolerance all matter and none of them appear in an ingredient list. Patch test anything new before it goes on your whole face. If irritation or breakouts keep repeating, or if you are pregnant or nursing, that is a conversation for a dermatologist rather than a tool.
- Regulation on the Review of Functional Cosmetics (Korea MFDS)
- Korean Cosmetic Ingredient Dictionary (Korea Cosmetic Association)
- CosIng database (European Commission)
Frequently asked
What is this based on?
The verdicts come from the ingredient pairing articles on this site. When a pair has its own article, you get that article's conclusion and a link to it. When it doesn't, the answer comes from the three principles those articles established, and the card says so.
What is the difference between the two source labels?
One means we wrote an article about that specific pair. The other means we answered from the general principles: irritating actives don't stack, gentle ingredients go anywhere, sunscreen is always part of the set. Pairs of gentle ingredients have no more precise answer than that, so the principle-based reply is the full answer.
Does 'take care' mean I can never use them together?
No. It usually means don't put them on the same night. Morning and evening, or alternating days, and most of these pairs work fine. The tip on each card tells you how to split them.
It said fine together but my skin reacted.
The verdict describes how two ingredients behave in general. It cannot account for the rest of the formula or for your skin. Products carry fragrance, preservatives and alcohol too, and people differ. Patch test anything new, and see a dermatologist if irritation keeps repeating.
Why does it ask about my skin type but not my age or gender?
Skin type changes the advice we can give, so we ask. Age and gender do not change how two ingredients interact, so asking would only make the tool look more precise than it is.
My ingredient isn't in the list.
The list covers the ingredients people ask about most. We add more as articles go up, and we prioritize what gets searched.