Hair oils & serums – INCI lists and analysis

Hair oils and serums are mostly leave-on products applied in small amounts to damp or dry lengths, especially the ends. Some people also use oils before washing as a pre-shampoo treatment. The category spans pure single oils, blends of several plant oils, and lightweight serums whose texture comes from silicones or esters rather than oils.

Plant oils appear under their Latin INCI names, for example ARGANIA SPINOSA KERNEL OIL, COCOS NUCIFERA OIL, SIMMONDSIA CHINENSIS SEED OIL or CAMELLIA OLEIFERA SEED OIL. Serums often list DIMETHICONE, DIMETHICONOL, CYCLOPENTASILOXANE or alternatives such as C13-15 ALKANE and COCO-CAPRYLATE/CAPRATE at the top, with plant oils further down. Some products are simply one oil, with a single-line INCI list.

Some cyclic silicones, namely D4, D5 and D6, are subject to restrictions under the EU REACH regulation, which has led many manufacturers to reformulate. Anhydrous oils and serums usually contain no water and often no classic preservative, but they may include TOCOPHEROL as an antioxidant to slow down rancidity. Products that combine oils with water are emulsions and do need preservatives.

Fragrance is very common in this category. Look at the end of the list for PARFUM and named allergens such as LINALOOL, LIMONENE, BENZYL SALICYLATE or HEXYL CINNAMAL. If a particular oil is featured on the front of the bottle, its position in the list shows whether it forms the base or is a minor addition.