Ten apps built for different questions: Yuka and Think Dirty let one ingredient set the score, SkinSAFE screens for Mayo Clinic's common allergens, INKEEDecoder gives no score at all, and a year of the priciest tier we read costs $259.48.
SlipperSkin finding
Of 10 ingredient checker apps whose methods we read between 21 and 23 October 2026, two let the worst ingredient set the whole score (Yuka and Think Dirty), one weights toward it (EWG Skin Deep), none factors dose into the score, and three publish a way for brands to pay.
The one built for your question; they are not ten answers to one question:
Start from the question, not the app. Each branch below goes to the app whose own method page says it is built for that question; the short line under each name is the rule it publishes.
Seven questions, asked of each app's own method page. The two that matter most are the two least visible in the apps themselves. Two apps, Yuka and Think Dirty, let the worst ingredient decide: Yuka holds any product with a high-risk ingredient between 0 and 24 out of 100, and Think Dirty rates a product no lower than its highest-rated ingredient. And none of the 10 folds dose into the score; EWG says plainly its rating "does not account for exposure".
| App | The question it answers | How the score is built | US App Store |
|---|---|---|---|
| Yuka | How risky are the ingredients, by the worst one? | Four colour tiers per ingredient; the riskiest ingredient sets the band the score can fall in. Method | 4.8 from 101,324 |
| Think Dirty | Does anything in it carry documented harm? | A 0 to 10 Dirty Meter; by default no lower than the worst ingredient, and 7 or more if "fragrance" is listed. Method | 4.8 from 56,771 |
| EWG Skin Deep | How hazardous are the ingredients, on the evidence? | 17 hazard categories; per category the worst ingredient plus the average of the rest, then weighted and scaled 1 to 10. Method | 4.1 from 3,559 |
| SkinSAFE | Is it free of the common contact allergens? | SkinSAFE 100 ranks how free a product is of the most common allergy-causing ingredients identified by Mayo Clinic. Method | 4.6 from 1,916 |
| SkinSort | Does it suit my skin, and will it clog pores? | A personal Match Score out of 100 from your skin type, concerns and liked or avoided ingredients; comedogenic ratings 0 to 5. Method | 4.7 from 6,416 |
| INKEEDecoder | What does each ingredient actually do? | No product score at all: each ingredient gets a role, a superstar, goodie or icky rating, and irritancy and comedogenicity on 0 to 5. Method | web only |
| Skincarisma | What share of the list does EWG rate risky? | Publishes its whole formula: 100 minus the moderate-risk share times 0.45, minus the high-risk share. Method | web only |
| INCI Beauty | How controversial is the formula, including origin? | A score out of 20 from five flower colours, with a progressive penalty as at-risk ingredients add up. Method | 4.8 from 1,439 |
| Clearya | Is anything here on a hazard list? | No score: an alert naming the list, the hazard and its conditions, in a browser extension and app. Method | app; rating not re-read |
| OnSkin | A quick verdict, out of 100? | Excellent to Bad with a score out of 100, from criteria including allergy risk and "high-concentration alerts"; the formula is not published. Method | 4.7 from 33,370 |
Yuka is the most rated app here (101,324 US App Store ratings) and the only one that publishes its revenue: $11,884,771 from Premium subscriptions in 2025, and nothing from brands. Think Dirty rates against a long appendix of agencies and adds a rule of its own: any product listing "fragrance" gets 7 or more, which is why fragranced products rarely look good there. EWG Skin Deep is the deepest hazard database and the most candid about its limit. SkinSAFE, built with Mayo Clinic, is the one to use if a dermatologist has given you a list of allergens to avoid. SkinSort and INKEEDecoder are the two built around pores and what ingredients do; SkinSort, INKEEDecoder and Skincarisma carry comedogenic ratings, mostly from rabbit-ear tests that INKEEDecoder itself warns used undiluted ingredients. Skincarisma is the only one that prints its whole formula. INCI Beauty is France's equivalent and scores origin as well as health. Clearya is free, takes no brand money and gives alerts rather than a score.
Between nothing and $259.48. Clearya and the two websites, INKEEDecoder and Skincarisma, are free. Among paid tiers, the weekly plan is the expensive habit: OnSkin's $4.99 weekly access is $259.48 over a year. Monthly plans are the next trap: SkinSAFE's monthly plan costs more than its annual plan by month 7 and $47.89 more over a year; SkinSort's by month 6 and $55.89 more.
It matters for what you see first, if not for the score. Three of the 10 publish a way for brands to pay: Think Dirty listed a $322 per SKU review fee followed by monthly licensing when we read it on 21 October 2026, with "Pinned Results" for partners; EWG charges a non-refundable $750 per formulation for its VERIFIED mark, and VERIFIED products are listed first in search results; INCI Beauty sells in-app advertising to brands. Yuka, Clearya, Skincarisma and OnSkin say they take no brand money. The full map is in who pays the ingredient apps, and the three biggest rules are drawn side by side in Yuka vs Think Dirty vs EWG.
1. Write your question in five words. Allergy? Pores? Hazard? What it does? 2. Match it: allergy = SkinSAFE, pores = SkinSort, "what does it do" = INKEEDecoder, hazard = EWG, aisle verdict = Yuka or Think Dirty. 3. Check the rule: does one ingredient set the whole score? (Yuka, Think Dirty: yes.) 4. Check the list against your box before you trust any score; formulas change. 5. Price it per year, not per week.
We read each app's own method page, help articles and US App Store listing on 23 October 2026 and answered seven fixed questions for each, recording the line and page behind every answer. Think Dirty's site refused automated reading on 23 October 2026, so its method and fee pages are as read on 21 October 2026; its App Store listing was re-read on 23 October 2026. CosDNA blocked automated reading on both days and is left out rather than guessed. Prices are US App Store or maker prices on the read date; a year of a weekly or monthly plan is computed at 52 weeks or 12 months. This compares what the apps publish about themselves; it is not a test of any product, and SlipperSkin gives no safety verdict on any ingredient.
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It depends on your question. SkinSAFE screens for common contact allergens, SkinSort for pore-clogging and fit, INKEEDecoder explains ingredients without a score, EWG Skin Deep rates hazard with named sources, and Yuka or Think Dirty give a quick aisle verdict set by the worst ingredient.
Not in the score. Of the 10 apps we read, 3 mention concentration (Think Dirty, INKEEDecoder and OnSkin), but none folds dose into the product score. EWG says its rating "does not account for exposure", and Skincarisma says it "can't account for how much" of each ingredient is present.
Because Yuka publishes that rule: the riskiest ingredient sets the range. A high-risk (red) ingredient keeps the score between 0 and 24 out of 100, a moderate-risk (orange) one between 0 and 49. Think Dirty works the same way, rating a product no lower than its highest-rated ingredient.
Yes. INCIDecoder renamed itself INKEEDecoder after the Personal Care Products Council, which runs the INCI naming system, filed a US trademark lawsuit over the name. The site says the dispute has been resolved; the database and the incidecoder.com address carry on.
Three of the 10 publish a way: Think Dirty (a $322 per SKU review fee then licensing, as read on 21 October 2026), EWG (a $750 per formulation fee for EWG VERIFIED, whose products are listed first in search) and INCI Beauty (in-app advertising). SkinSAFE runs a Trusted Choice programme without a published fee. Yuka, Clearya, Skincarisma and OnSkin say they take no brand money.
Clearya is free with no ads, funded by donations. INKEEDecoder and Skincarisma are free websites, and Yuka, EWG and SkinSAFE all let you scan for free with paid extras.
There is no single best ingredient checker, because the 10 apps here answer different questions with different rules. Choose the one whose question is yours, know whether one ingredient decides its score, check its ingredient list against your box, and pay by the year if you pay at all.