Free tool from Corium 21
Ingredient Label Decoder: estimate what's really in your lotion
Paste any lotion's ingredient list to see what's in it and roughly how much.
Free, no sign-up, and nothing you paste leaves your browser.
Decoder
The 1% rule, explained
In the United States (FDA, 21 CFR 701.3) and the European Union (Regulation (EC) No 1223/2009), cosmetic ingredients present at more than 1% must be listed in descending order of concentration. Ingredients at 1% or less can follow in any order, and colorants can go at the very end. So the first few ingredients make up most of the jar, and somewhere in every list sits an invisible "1% line."
You can usually find it. Some ingredients are almost never used above 1%: preservatives (phenoxyethanol, parabens, ethylhexylglycerin, sodium benzoate, potassium sorbate), fragrance or parfum, colorants (CI numbers), chelators (ingredients that bind minerals in water) such as disodium EDTA, pH adjusters such as citric acid, and most plant extracts and vitamins. When you reach the first of these, that ingredient and everything after it is most likely at or below 1%. This method is described by cosmetic chemist Perry Romanowski at Chemists Corner (figuring out the 1% line and how to analyze an ingredient list).
How the decoder works
- Reads the list. It splits the label into ingredients and handles prefixes, line breaks, common names in parentheses, "(and)" blends and "May contain" colors.
- Finds the 1% line. It looks for the first ingredient almost always used at 1% or less.
- Estimates ranges. For ingredients above the line, it starts from typical use levels in lotions and creams, then narrows each range so the list stays in descending order and adds up to 100%. Ingredients below the line show as "≤1%."
- Explains each ingredient. It says what each one does (humectant, which draws water into skin; emollient, which softens and smooths; occlusive, which forms a light seal that slows water loss; emulsifier, which keeps oil and water blended; preservative and so on) and notes ones people with sensitive or eczema-prone skin often watch for, like fragrance, some essential oils and methylisothiazolinone (a preservative).
Our database covers more than 200 of the most common moisturizer ingredients. Ingredients it doesn't know are still sorted by name patterns (for example, names ending in "extract" or "butter") and marked "not in our database."
Limits: formulators sometimes use unusual amounts, and drug-labeled products often list inactive ingredients alphabetically. Treat every number as a rough estimate. Flags are general information, not medical advice; if you have a skin condition, a dermatologist can help you choose products.
Frequently asked questions
What is the "1% line" on an ingredient list?
It's the point after which every ingredient is at 1% or less. Ingredients above 1% must be listed from most to least, but those at or below 1% can appear in any order. The line isn't printed, so you estimate it from the first ingredient that is almost always used at 1% or less, such as a preservative or fragrance.
Are cosmetic ingredients listed in order of concentration?
Yes, for ingredients above 1%. In the US and EU those must be listed in descending order. Ingredients at 1% or less, and colorants, can follow in any order. That's why the first five or so ingredients usually make up most of a lotion.
How accurate are the percentage estimates?
They're rough ranges, not measurements, based on label order, typical use levels and the fact that everything adds up to 100%. Water in a typical lotion often lands around 60–80%. Only the formula or a lab test gives exact numbers.
Why is fragrance flagged for sensitive or eczema-prone skin?
Fragrance is one of the most common causes of skin reactions to cosmetics, and one "fragrance" entry can stand for dozens of compounds. Many people with sensitive or eczema-prone skin choose fragrance-free products for that reason. The flag is information, not a verdict.
Why are some ingredient lists in alphabetical order?
US products sold as over-the-counter drugs, such as skin protectants with an "Active ingredients" panel, follow drug labeling rules, and their inactive ingredients are often listed alphabetically. The 1% rule doesn't apply to those lists, and the decoder warns you when a list looks alphabetical.
Does the decoder save or send what I paste?
No. Everything runs in your browser. The list you paste is never uploaded, stored or shared.
Link to this tool
Writing about skin care ingredients? You're welcome to link to the decoder. Copy this HTML:
<a href="https://corium21.com/pages/ingredient-label-decoder">Ingredient Label Decoder by Corium 21</a>
Built by Corium 21, a small family-owned skin care brand. Trusted since 1994. Family-owned in Oregon. Last updated October 2026. Looking for a simple, aloe-based cream for dry, working hands? See Corium 21.