How to read an ingredient list

An ingredient list looks impenetrable because it uses a naming standard rather than marketing names. That standard — INCI, the International Nomenclature of Cosmetic Ingredients — exists so that the same material carries the same name on every package in every market. Water is Aqua. Vitamin B3 is Niacinamide. It is a translation problem, not a secrecy problem.

Ingredients present above one percent are listed in descending order of concentration. That tells you what the formula is mostly made of. Below one percent, ingredients may be listed in any order, which is why an ingredient near the end of a long list could be at 0.9 percent or 0.001 percent.

This single rule defeats most label-reading shortcuts. Seeing a well-known ingredient in position twenty tells you it is below one percent. It does not tell you whether it is present at a useful level, because many effective materials are used well under one percent by design.

A typical formula contains a base, a thickening system, an emulsifier if oil and water are combined, a preservative system, a chelating agent, pH adjusters, and often fragrance. None of these are filler. Remove the preservative system and the product becomes unsafe within weeks. Remove the emulsifier and it separates.

• —The first five ingredients — this is what the product mostly is.
• —Whether the ingredients you care about appear above or below the one percent line.
• —Whether fragrance is present, if that matters to you.
• —Whether the product is anhydrous — no water listed usually means an oil, balm, or stick.