Reading an ingredients list without a chemistry degree

The ingredients list on the back of a bottle follows a legal rule. Once you know the rule, an ingredients list tells you most of what you need in about ten seconds.

The rule

In the US and the EU, ingredients have to be listed in order of how much of each is in the formula, largest first. That rule holds until you reach ingredients at 1% or less. From there down, the brand can list them in any order.

So the list has two parts. The top shows you what the product is mostly made of. The bottom is a group of small amounts in no particular order.

Finding the 1% line

The list doesn't mark where 1% falls, but it often gives you a clue.

Phenoxyethanol is one of the most common preservatives, and in the EU it is capped at 1%. Wherever it appears, everything after it is at 1% or less. Other common markers are fragrance, which is rarely more than 1%, and thickeners like xanthan gum, which are usually well under it.

If a product's hero ingredient sits below phenoxyethanol, there is very little of it. That is worth knowing when the front of the bottle is all about it.

What the top of the list tells you

• Water, or aqua, is first in most creams and serums. It is often 60 to 80% of the formula. That is normal. It carries everything else.
• The next four or five ingredients are most of what's left. In a cream, expect oils, butters, glycerin and emulsifiers. In a serum, expect glycerin and the main active.
• A percentage on the front should match a position near the top. Niacinamide Serum is 10% niacinamide, so it comes right after water. Vitamin C Serum is 15% vitamin C, listed as ascorbic acid, in the same place.

When low on the list is fine

Some ingredients do their job at very small amounts. Retinal is one. Retinal Night Serum is 0.05% retinal, which puts it well below the 1% line, and that is the right amount. More would irritate your skin.

Peptides, some antioxidants and preservatives also work at under 1%. So low on the list means small, not weak. What matters is whether the amount matches what that ingredient needs.

Names that look strange

Ingredient lists use a standard naming system, called INCI, so the same ingredient has the same name everywhere. Plants are listed by their Latin names. A few you'll see often:

• Butyrospermum parkii butter is shea butter.
• Simmondsia chinensis seed oil is jojoba oil.
• Tocopherol is vitamin E.
• Sodium hyaluronate is a form of hyaluronic acid.
• CI 77491, 77492, 77499 are iron oxides, the pigments in Tinted SPF 30. Colors are always listed at the end.

A long chemical name is not a warning sign. Water has one too.

What to look for

Read the first five ingredients to see what the product is. Find the preservative to see where 1% falls. Check that anything the front makes a promise about sits where it should. And if your skin is sensitive, scan for fragrance, parfum and essential oils.

That covers most of it. You don't need to know what every ingredient does. You only need to know where to look.