Everything you need to know about black seed vegetable oil.

The nigella, also known as black cumin, is an aromatic plant with pretty blue flowers that primarily grows in Egypt. In addition to its aesthetic properties, it produces a large quantity of aromatic black seeds each year, which are often found in oriental dishes. The cultivation of nigella dates back to antiquity. The ancient Egyptians regarded it as a cure-all and called it "the blessed seed". It was also used by the Greeks and Romans for its therapeutic properties. From the seeds of nigella, it is possible to extract an oil that is used in the composition of many treatments for the skin and hair under its INCI name Nigella Sativa Seed Oil.

Theblack seed oil is a natural ingredient rich in intriguing molecules, responsible for the various benefits it provides to the skin and hair. The table below summarises the different active principles found in black seed oil, as well as the main properties associated with them.

There are several methods for extractingblack seed oil from its seeds, but the technique to favour in order to keep all its active principles intact and all its benefits is cold pressing. In practical terms, a screw press is used to push the seeds into a barrel-shaped cavity. The screw then compresses them and the oil comes out through the openings, while the pressing residues (cake) remain in the barrel. The oil thus collected is finally filtered to remove impurities and stored away from light, moisture and air.

Note : 1 kg of black cumin seeds yields approximately 200 to 250 mL of black seed oil.

When applied topically or to the hair, black seed oil provides numerous benefits.

• Hydrating.

  Naturally present in the hydrolipidic film of the skin, the saturated fatty acids from black seed oil form a protective veil on the epidermis. This film acts like a shield on the skin and notably helps to protect it from UV rays, pollution, and dehydration. The hydrolipidic film is also found around hair fibres, where it plays a similar protective role.

• Nourishing.

  The linoleic acid found in black seed oil contributes to the restoration and maintenance of the protective corneal layer of the epidermis. Indeed, when linoleic acid comes into contact with the ceramides of this layer, an esterification reaction occurs, during which the linoleic acid and lipids bind, forming the skin's waterproof barrier.

  Black seed oil can also be used as a hair treatment to nourish and strengthen hair fibres. The palmitic acid it contains, which has a structure similar to the lipids that make up the cuticle of the hair, can integrate into it and act as an intercellular cement. Black seed oil thus protects fine and fragile hair and makes it shinier.

• Antioxidant.

  The antioxidant properties of black seed oil are derived from its thymoquinone. This molecule has a protective effect on cellular organelles and DNA, defending the skin and hair fibres against the action of free radicals. Indeed, these reactive and unstable species can notably cause genetic mutations and are involved in the premature ageing of the skin and the appearance of white hair. Thus, black seed oil has a photoprotective potential and is an excellent ally for preventing the appearance of wrinkles.

• Anti-inflammatory.

  Studies have shown that thymoquinone is also capable of reducing the production of interleukins-1β, 2 and 6 (IL-1β, IL-2 and IL-6), which are pro-inflammatory cytokines. Thymoquinone also inhibits the expression of cyclooxygenase (COX), an enzyme that catalyses the conversion of arachidonic acid into prostaglandin H2, thereby increasing inflammation. This makes black seed oil a good ingredient for combating redness and itching. It can also be used as a supplement by people suffering from acne, eczema, psoriasis or rosacea.

• Healing.

  Theblack seed oil can, to some extent, combat acne marks and stretch marks. Its healing properties were notably highlighted in a recent study conducted on injured rats. Scientists demonstrated that, following the application of a gel containing 10% black seed oil and the placement of a dressing for 7 days, the sizes of the rats' wounds were reduced by 40%. The mechanism explaining the healing effects of black seed oil has not yet been identified, but these have been substantiated by several studies.

Black seed oil can be applied to the skin, scalp or hair. It is suitable for all skin types and can be used by pregnant women for external application. However, it is not suitable for mucous membranes or the eye contour. Therefore, if you use black seed oil on your face, it is important to avoid any contact with the eyes. Moreover, it is crucial to dilute the black seed oil in another vegetable oil before applying it. A dilution of 5 to 10%, depending on your skin's sensitivity, is generally recommended.

Finally, it is important to note that black seed oil can be allergenic for some individuals. Therefore, before incorporating it into your skincare routine, we advise you to carry out a tolerance test, to ensure that your skin does not react to this ingredient. To do this, apply a small amount of black seed oil to the inside of your elbow or behind your ear and wait 24 hours. If you do not observe any redness, irritation or itching, you can use it.

• SUTRISNA E. & al. A Comparative Study of the Effects of Nigella sativa Oil Gel and Aloe Vera Gel on Wound Healing in Diabetic Rats. Journal of evidence-based integrative medicine (2018).

• AL-FARGA A. & al. A Narrative Review on Various Oil Extraction Methods, Encapsulation Processes, Fatty Acid Profiles, Oxidative Stability, and Medicinal Properties of Black Seed ( Nigella sativa). Foods (2022).