As the name suggests, the "unsaponifiable" fraction of a vegetable oil represents the elementsthat are not transformed into soap during a saponification reaction. These include sterols, hydrocarbons (squalene, etc...), fatty alcohols (waxes, etc...), liposoluble pigments, vitamins, polyphenols, minerals, etc... Generally, this unsaponifiable fraction only accounts for 0.5 to 2% of vegetable oils.
Hazelnut oil contains 0.3% to 0.7% unsaponifiable matter, primarily composed of vitamin E and phytosterols, potentnatural antioxidants.They protect the skin and hair from the damaging effects of free radicals, which arereactive oxygen speciesproduced naturally by the body but overproduced when cells are exposed tostress. Stress sources are numerous, the main ones being UV exposure, pollution, smoking, and a diet too rich in fats and/or sugars. Free radicals are particularly unstable molecules due to theirsingle electron. They tend to react with other molecules to form anelectron pair, thereby causingdamage to the body's cells, DNA, and proteins. They are notably involved in lipid peroxidation, a degradation reaction of the constituents of cell membranes. This accelerates ageing and causes wrinkles to appear on the skin's surface. Regarding hair, free radicals weaken hair fibres, hastening their fall and/or the appearance of white hair. Therefore, hazelnut oil is a valuable ally in preventing skin ageing, combating the onset and/or accentuation of wrinkles, as well as the degradation of hair strength over time.