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Use ChekIt if you want a straight answer on whether something breaks you out. Use INCIDecoder if you want to nerd out about ingredient chemistry. Use CosDNA if you like spreadsheets and don't mind a site that looks like 2005.
If you have acne-prone skin, you've probably tried one of these. If you haven't, you will. These are the three most popular ingredient checkers on the internet.
We used all of them. Here's the honest take.
CosDNA has been around forever. It's the one everyone mentions in skincare forums. It's the grandparent of ingredient checkers — reliable, well-known, and showing its age.
It's built for chemists, not people with acne.
The interface is cluttered. You get raw data — not a verdict. You're left to figure out whether a 3/5 rating is "bad." There's no context on how ingredients interact with each other. And good luck using it on your phone.
People who already understand the comedogenic scale and just want the numbers. If you've been in the skincare game for years and know that butylene glycol at position 7 is different from coconut oil at position 3 — CosDNA gives you what you need.
CosDNA is fine. It's not bad. But it's not helpful either. It hands you a spreadsheet and says "good luck." For someone dealing with breakouts, that's not what they need.
INCIDecoder has a slicker design than CosDNA and dives deeper into what ingredients actually do. It attracts the skincare curious — people who want to understand what they're putting on their face.
It's too neutral. INCIDecoder won't tell you if something is bad.
From their own site: "We're not here to tell you what to buy or what ingredients to avoid."
That's great for avoiding liability. Terrific for covering all bases. But terrible for someone with acne who just wants to know: will this break me out?
They'll tell you that niacinamide helps with brightening but won't say "this product has three ingredients that are known pore-cloggers."
Curious skincare enthusiasts who want to understand ingredient chemistry. If you enjoy reading about the function of emulsifiers and humectants — INCIDecoder is genuinely interesting.
INCIDecoder is the best learning tool. The ingredient breakdowns are fascinating and you'll come away smarter. But as a decision-making tool for acne-prone skin? It's frustrating. Knowledge without guidance is just information overload.
ChekIt is built specifically for one thing: telling you if a product is safe for acne-prone skin. No fluff, no chemistry lesson — just a verdict.
Smaller product database than CosDNA or INCIDecoder. But here's the thing — you can paste any ingredient list. Doesn't matter if it's in their database.
Found a random Korean skincare product at an Asian supermarket? Paste the ingredients. ChekIt doesn't need to have seen it before.
ChekIt isn't trying to be everything to everyone. It solves one problem: "Is this safe for my acne?" That focus is exactly what makes it different.
"This product has ingredients rated 3, 4, and 5. Good luck!"
"This product contains various emollients and humectants. Here's what they do."
"This product has 3 pore-clogging ingredients. Not acne-safe. Here's which ones to avoid — and here are clean alternatives."
Three different approaches to the same problem.
Use all three — strategically:
ChekIt gives you the answer. The others give you the research.
Accuracy depends on what you're measuring. CosDNA and INCIDecoder have larger databases because they've been around longer. ChekIt analyzes ingredients dynamically — so it can evaluate products not in any database.
For acne-specific accuracy, ChekIt is purpose-built. The other two are general tools that weren't designed with acne in mind.
The comedogenic scale (0-5) is based on rabbit ear testing from the 1970s-80s. It's not perfect — everyone's skin reacts differently. But it's the best framework we have.
One thing that matters: ingredient position. An ingredient at position 20 matters less than one at position 3. CosDNA shows this. INCIDecoder shows this. ChekIt accounts for this automatically.
Different databases. Different rating systems. Different focus areas.
INCIDecoder weighs ingredient function (is this a good moisturizer?) ChekIt weighs pore-clogging potential (will this cause breakouts?) Same ingredient, different question — different answer.
Yes. Estheticians use all three, but ChekIt is designed specifically for professional use. The ability to quickly check a client's products during consultation is genuinely useful.
ChekIt's core features are free. CosDNA is free. INCIDecoder has a free tier.
For acne-prone skin specifically, ChekIt gives you the most value without paying.
If you have acne and just want to know if a product is safe: ChekIt.
If you're a skincare nerd who wants to understand the chemistry: INCIDecoder.
If you want raw data and don't mind a clunky interface: CosDNA.
Most people want the first one. They don't want to become ingredient scientists. They want clear skin.
Try ChekIt for free → — paste any ingredient list and get an instant verdict. If it's not acne-safe, we'll recommend clean alternatives.
