Every cosmetic sold in the EU must list its ingredients using INCI names, in descending order of concentration down to 1%. Below 1% the order is arbitrary. That single rule tells you most of what you need.
The first five matter most
If water (Aqua) is first, the product is mostly water — normal for a lotion, disappointing in a "pure" oil. If the active you are paying for appears after the preservatives, there is very little of it in there.
Words that are not what you think
- Fragrance / Parfum — can hide dozens of undisclosed compounds, and is the most common cause of cosmetic contact allergy
- Alcohol Denat. — drying; Cetearyl Alcohol is a fatty alcohol and is not
- Natural — legally meaningless on its own; look for a certification body instead
- Hypoallergenic — unregulated marketing term with no agreed standard
Preservatives are not the enemy
Any product containing water needs a preservative or it grows bacteria within weeks. Phenoxyethanol and sodium benzoate are well studied and safe at cosmetic concentrations. A water-based product with no preservative is a red flag.
Where the allergens hide
EU law requires 26 fragrance allergens to be named individually when present above a threshold — linalool, limonene, citronellol and geraniol among them. These occur naturally in essential oils, which is why botanical products are not automatically gentler than synthetic ones.