How to read an ingredient list
The order is the law, the first five are the product, and “fragrance” is a hiding place. A five-minute education.
An ingredient list is the only part of the packaging that is legally obliged to be true. Learn to read it and most of the rest of the box stops mattering.
The order is the law
Ingredients are listed by weight, in descending order, down to one percent. So the first five entries are, in practice, the product; everything after them is present in amounts a laboratory measures and your skin mostly does not notice.
Below one percent, the order is free — which is why the exciting molecule from the advertisement so often appears at the very end, sitting just behind the preservative.
Water is not a filler
Aqua at the top of the list is not a scandal. Most actives are water-soluble and have to be dissolved in something. What matters is what comes second.
Fragrance is a hiding place
“Parfum / Fragrance” can lawfully stand in for dozens of undeclared compounds, and it is the single most common cause of contact dermatitis in cosmetics. A brand that leaves it out is telling you something; a brand that leaves it in and does not say why is telling you something too.
Percentages, or it did not happen
An active without a number is a story. Niacinamide works at 4–5%, vitamin C at 10–20%, retinol at 0.3–1%. If the brand knows those numbers — and it does — the only reason not to print them is that the answer is disappointing.