Black seed oil: what are its benefits for hair?

Due to its composition rich in unsaturated fatty acids, nigella vegetable oil has a protective action on hair fibres. Indeed, the oleic acid it contains is naturally present in the hydrolipidic film coating the hair and acts as a shield to protect the fibres from external aggressions (UV, wind, temperature variations...). Nigella oil also contains palmitic acid, which has a structure similar to that of the lipids composing the cuticle of the hair. This active ingredient is thus able to insert itself and play the role of intercellular cement.

By contributing to the restoration and cohesion of the cuticle, palmitic acid and other saturated fatty acids in black seed oil also promote its impermeability and the protection of the inner layers of the hair fibre, such as the cortex. This is rich in keratin fibres, giving hair its flexibility and elasticity. Therefore, black seed vegetable oil is an interesting ingredient for dry or damaged hair.

Applying black seed oil to hair fibres also enhances their aesthetic appeal and shine. Indeed, as mentioned earlier, the saturated fatty acids present in this botanical extract can strengthen the cohesion between the scales of the cuticle. When the structure of the hair fibres is robust and the scales forming their cuticle are properly bonded, the hair appears more shiny, as it is better able to reflect light.

Black seed oil is a potent ally against scalp irritation, due to the presence of thymoquinone in its biochemical composition, its active ingredient. Indeed, this molecule possesses anti-inflammatory properties. Studies have particularly shown that thymoquinone reduces the production of pro-inflammatory cytokines, such as interleukins 6 and 12 (IL-6 and IL-12) and the tumour necrosis factor (TNF-α).

Furthermore, thymoquinone inhibits the signalling pathway related to the nuclear factor NF-κB. However, NF-κB plays a crucial role in the production of interleukins 1 and 2 (IL-1 and IL-2), other pro-inflammatory cytokines, as well as interferon-gamma (IFN-γ) in T lymphocytes. IFN-γ is a cytokine produced as part of the innate immune response and involved in the regulation of various inflammatory mechanisms. Thus, the application of black seed oil to the scalp can alleviate itching.

The thymoquinone found in black seed oil also has antioxidant properties, enabling it to combat free radicals and oxidative stress. Indeed, studies have shown that this molecule can enhance the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase, which are antioxidant enzymes.

Indeed, free radicals, generated following exposure to UV radiation or pollution, are reactive species that can weaken the hair follicle and promote hair loss and split ends. They are also capable of triggering a cascade of biochemical reactions leading to the degradation of melanin, the pigment that gives hair its colour, and thus accelerate their greying. The black seed oil helps to counter these mechanisms and protect hair fibres from oxidative stress.