Extracted from the seeds of Nigella sativa, the nigella oil has been used since antiquity in both dietary and cosmetic applications. For the skin, its main benefit is primarily based on its rich lipid composition, notably including linoleic acid and oleic acid, with nourishing properties, and on the presence of unsaponifiable compounds, such as thymoquinone, which exhibit anti-inflammatory and antioxidant properties.
Nigella oil thus appears to be an interesting botanical ingredient for caring for dry skin.
As a reminder, dry skin is characterized by an insufficient hydrolipidic film and impaired barrier function. This weakening is mainly related to a reduction in epidermal lipids, particularly ceramides, as well as a decrease in natural moisturizing factors (NMF), essential for retaining water in the stratum corneum. Thanks to their chemical structure similar to that of stratum corneum lipids, the fatty acids present in the nigella oil contribute to the restoration of the intercellular lipid matrix. By integrating into the lipid structures of the stratum corneum, they help limit transepidermal water loss and improve the comfort of dry skin.
Moreover, oleic acid, which accounts for nearly 25% of black cumin seed oil, is part of the hydrolipid film of the skin. A topical application of black cumin seed oil helps to reinforce this protective shield semi-aqueous, semi-lipid, which is often fragile in dry skin.
By supporting the skin barrier and compensating for the lipid deficits characteristic of dry skin, Nigella sativa oil offers enhanced comfort.
Beyond mere skin dryness, some data also suggest a potential benefit of nigella oil in pathological dry skin settings, such as eczema. This chronic inflammatory disorder is indeed accompanied by significant disruption of the skin barrier, a deficiency in epidermal lipids, and increased water loss, accounting for the close association between eczema and skin dryness. A controlled, double-blind clinical study thus investigated the effect of a topical preparation containing 2% Nigella sativa to target hand eczema, a common form of eczema. Sixty patients were divided into three groups receiving either a nigella-based ointment, a betamethasone-based ointment, a corticosteroid reference, or a standard emollient, each applied twice daily for four weeks. The evaluation was based on two primary endpoints: eczema severity, measured by the Hand Eczema Severity Index (HECSI), and the impact on quality of life, assessed by the Dermatology Life Quality Index (DLQI).
The results showed a faster and more pronounced improvement of eczema in the Nigella and betamethasone groups compared with the emollient group.