Understand the ingredient list—not just the ingredient names.
Every ingredient checker turns a list of chemical names into something that feels like a verdict. It is worth being clear-eyed about how much of that verdict the ingredient list can actually support — because the honest answer changes how you should use one.
What an ingredient checker is
An ingredient checker takes the INCI list — the standardised chemical names printed on the package — and does three things with it: recognises each entry, attaches information to it, and summarises the result. The recognition step is the one that carries the most weight and gets the least attention. INCI names are a controlled vocabulary, so an ingredient either resolves to a known entry or it does not. Products that mix in trade names, botanical synonyms, or a Korean transliteration of a Latin name are where checkers quietly fail.
What you can genuinely learn from an ingredient list
- What is in it. This sounds trivial and is the main event. If you are avoiding a specific material — a fragrance allergen you react to, an oil that breaks you out, alcohol high in the list — the list answers that question definitively.
- Roughly how much of the top few. Ingredients are listed in descending order by weight, so the first several entries tell you what the product substantially is: a water-based gel, an oil blend, a silicone-heavy primer.
- Category. An experienced reader can usually tell a cream from a hydrating toner from an occlusive balm from the list alone.
- Whether a headline claim is plausible. If the front of the pack leads with an ingredient that appears twenty-ninth, that is informative.
What no ingredient checker can tell you
Concentrations
Ingredient lists do not carry percentages. Ordering is strict only down to the 1% threshold; at 1% or below, ingredients may be listed in any order. Most actives are used well under 1%. So for the part of the list people care most about, the position of a name carries no information about quantity at all. Any tool that appears to score the back half of a list by position is reading a ranking that is not there.
Formulation
The same ingredients at the same concentrations can produce products that behave completely differently depending on pH, particle size, the delivery system, and what else is in the jar. Two lists can look near-identical and perform nothing alike. This is the single largest gap between what a list shows and what a product does.
How your skin will respond
This is the important one. An ingredient being present tells you nothing about whether you will react to it. Irritation and sensitisation are individual, dose-dependent and often context-dependent. A checker can tell you a material is present; it cannot tell you the product will suit you, and it should not tell you a product is unsafe.
"Good" and "bad" ingredient scores are the weakest part
Blanket hazard scoring is where ingredient tools tend to overreach. A rating that labels a material dangerous without reference to concentration, exposure route, or the regulatory limits it is used under is not an assessment — it is a vibe attached to a name. Cosmetic ingredients are used within concentration limits set by regulators precisely because dose is what determines effect.
A more useful frame is factual and personal rather than universal and moral: is this specific thing I have decided to avoid present in this product, yes or no? That question an ingredient list can answer well.
How to evaluate an ingredient checker
- Does it show you the actual ingredient list, or only a score derived from it?
- Does it tell you when it could not read or resolve an ingredient, rather than silently dropping it?
- Does it distinguish "this ingredient is present" from "this product is bad for you"?
- Does it let you define what you avoid, rather than imposing a universal list?
- Does it say where its information came from, and when the product was last read?
How Kotiful approaches it
Kotiful reads the ingredient list off the product in front of you and resolves it against the INCI vocabulary, then reports two separate things and keeps them separate: what the label says, and how that compares to the profile you saved. A flag is phrased as a fact about the list — this ingredient is present, and it is on your avoid list — rather than as a verdict on the product. When the ingredient list cannot be verified, it says so instead of scoring anyway, because a confident score derived from an unreadable list is worse than no score.
Ingredient library
One page per ingredient, each built on the same catalog counts this site uses everywhere: how often it is listed across 7,878 parsed Korean products, where it concentrates, what it is usually paired with, and how it reads on a Korean label.