How to Read a Cosmetic Ingredient List

An ingredient list looks like a wall of unfamiliar words. In practice it follows a few rules, and once you know them you can compare two products in under a minute.

The Order Is the Story

In the United States, ingredients must be listed in descending order of concentration, down to 1 percent. Below 1 percent, they may be listed in any order. That single rule tells you more than any marketing line on the front of the package.

• Water or a similar base is usually first, because it is the largest ingredient by weight in most lotions and cleansers.
• Emollients, humectants and actives appear in the middle in roughly the order of their amounts.
• Preservatives, fragrance, colorants and antioxidants sit near the end, because small amounts are enough.

Two products with the same headline ingredient can differ sharply: in one, it may sit third; in the other, it may sit after the preservative, meaning under 1 percent.

Names That Look Alarming but Are Not

Cosmetic labeling uses International Nomenclature of Cosmetic Ingredients (INCI) names, which are systematic rather than descriptive.

• Sodium chloride is salt.
• Tocopherol is vitamin E.
• Glycerin is a common humectant.
• Butyrospermum parkii butter is shea butter.
• Aqua is water.

A long chemical name describes a molecule's structure. It does not describe risk, and a short botanical name does not guarantee safety. Some of the most irritating ingredients in cosmetics have familiar names, and some of the safest have unpronounceable ones.

Fragrance, Flavor and Trade Secrets

The word "fragrance" or "parfum" can stand in for a mixture of many compounds, because fragrance formulas are treated as confidential. That matters for anyone who reacts to scented products: "fragrance-free" and "unscented" mean different things, and only a product labeled fragrance-free is formulated without added fragrance.

Comparing Two Products

Use this sequence:

1. Check the first five ingredients. They define what the product mostly is.
2. Find the ingredient you care about. Note its position relative to the preservative, which is a useful marker for the 1 percent line.
3. Read the end of the list for fragrance, dyes and preservatives you want to avoid.
4. Compare the same product type, since a cleanser and a cream are not directly comparable.

What the List Does Not Tell You

Concentration order is not a dose. A product can contain an ingredient at a level too low to do anything, or at a level that irritates. The list also says nothing about the quality of a raw material or how the finished formula performs on your skin.

If you react to a product, bring the ingredient list to a dermatologist rather than guessing which line caused it. A patch test, done properly, is the reliable way to find a culprit.

For more on specific terms, see what is glycerin in skin care and fragrance-free vs unscented in personal care.