Does sesame oil darken the hair?

Sesame, or Sesamum Indicum, is an annual plant native to India that has been cultivated for nearly three millennia. From its seeds, it is possible to extract a vegetable oil that exhibits a high oxidative stability. The sesame oil possesses moisturising, anti-inflammatory, and antioxidant properties, making it a favoured ingredient in haircare formulations. Its high fatty acid content notably strengthens the structure of the hair fibre and promotes its impermeability. Sesame oil also combats oxidative stress, which is harmful to the scalp and hair fibres.

In search of a natural method to darken their hair without causing damage, many people are turning their attention to vegetable oils. Among these, some are wondering if sesame oil could be an option, due to the black colour that some of its seeds can have. Indeed, depending on the variety, sesame seeds can be white or black. The colour of the latter primarily comes from the anthocyanins they contain, flavonoids with pigmentation properties.

Indeed, hair pigmentation is due to melanin, a pigment synthesised in varying amounts by melanocytes. The higher the quantity of melanin produced, the more intense and dark the hair pigmentation. The type of melanin synthesised also matters. There are two types: eumelanin is associated with dark-coloured hair and pheomelanin results in blonde to red hair. In summary, it is the quantity and ratio of eumelanin and pheomelanin produced that determine hair colour. Even though the application of sesame oil brings many benefits to the hair, it cannot influence this ratio and it does not have an immediate darkening effect either.

Note : Studies in vitro suggest that sesame oil could slow down the onset of white hair by stimulating the activity of tyrosinase, the enzyme that catalyses the transformation of tyrosine into melanin. It could thus help to preserve the natural colour of the hair, without however altering their pigmentation or darkening them.