Nigella sativa oil, an ally for hair health?

Benefit No. 1: Nigella sativa oil may strengthen hair.

Although no clinical study has formally demonstrated that applying nigella sativa oil strengthens hair, its composition suggests it may play a role in the protection and resilience of hair fibres.

The black cumin seed oil is very rich in unsaturated fatty acids, including oleic acid. The latter is naturally present in the hydrolipidic film that coats the hair fibres, a semi-aqueous, semi-greasy protective mixture responsible for limiting dehydration and reducing the impact of external aggressors (UV rays, wind, temperature fluctuations…). By supplying lipids similar to those physiologically found on the hair surface, the application of black cumin seed oil to the hair may help strengthen this lipid barrier — although this effect has yet to be quantified.

It also contains a significant proportion of palmitic acid, a saturated fatty acid whose structure resembles that of the lipids found in the cuticle, the hair’s outer layer. By analogy with other plant oils containing saturated fatty acids, it is plausible that these lipids could insert themselves between the scales and contribute to a better cohesion of the cuticle. However, a more coherent cuticle reduces the porosity of the fibre, offering the cortex, the intermediate layer rich in keratin and essential to hair elasticity, indirect mechanical protection. It is this mechanism that suggests the use of black cumin seed oil could be relevant for dry, weakened or damaged hair, even though its efficacy remains to be demonstrated.

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Benefit No. 2: Nigella oil could make hair shinier.

Applying black cumin seed oil to the hair fibres may also impart an attractive appearance and shine. As noted above, the saturated fatty acids present in this botanical extract could strengthen the cohesion between the cuticle scales.

When the structure of hair fibres is robust and the scales forming their cuticle are properly bonded, hair appears shinier because it is better able to reflect light.

In the absence of clinical data, this effect of nigella oil remains hypothetical but is consistent with what we know of cuticle biology. Moreover, the application of a vegetable oil such as nigella oil also forms a lipid film on the surface, which imparts an immediate gloss and helps to visually enhance the hair’s radiance.

Benefit No. 3: Nigella sativa seed oil may soothe an itchy scalp.

Black seed oil may also help soothe tingling and itching of the scalp thanks to thymoquinone, a compound with anti-inflammatory properties. This molecule helps to reduce the production of substances responsible for inflammation and to calm excessive skin reactions. Several studies conducted on the skin suggest that black seed oil has genuine soothing potential. In a classical experimental model of cutaneous inflammation (carrageenan-induced oedema), a balm containing 10% black seed oil reduced inflammation in a manner comparable to that of a reference anti-inflammatory (hydrocortisone). These results suggest that its application to the scalp could contribute to alleviating discomfort associated with inflammation.

60.64%

Inhibition of oedema in the 10% Nigella oil group.

43.55%

Inhibition of the leucocyte count in the 10% Nigella oil group compared with the control group.

Even though these data stem from an animal model and cannot be directly extrapolated to the human scalp, they support the notion that nigella oil may soothe itching in hair care.

Concentration de TNF-α dans un modèle murin d'inflammation et évaluation de l'effet de solutions topiques d'huile de nigelle et d'hydrocortisone. — TNF-α concentration in a murine model of inflammation and evaluation of the effect of topical nigella oil and hydrocortisone solutions.
Source : GANTINI S. N. & al. The anti-inflammatory activity of Nigella sativa balm sticks. Scientia Pharmaceutica (2019).

Benefit No. 4: Nigella sativa oil may prevent the onset of grey hair and the formation of split ends.

Nigella oil is often cited for its antioxidant potential, largely thanks to thymoquinone. Several studies conducted on the skin have shown that this molecule and, more broadly, nigella oil, can stimulate the activity of endogenous antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase. These enzymes play a key role in neutralising the free radicals.

Although no study has directly evaluated this effect of nigella oil on hair, it is plausible that its antioxidant potential could, at least in theory, contribute to protecting hair fibres from oxidative stress.

The latter is a well-known factor in the onset of two hair concerns: the premature bleaching of the fibres and the weakening of the ends. On the one hand, free radicals can initiate a cascade of biochemical reactions that progressively oxidise the melanin in the cortex, thereby accelerating the appearance of grey hair. In theory, an antioxidant-rich ingredient, such as black seed oil, could help to preserve melanin’s integrity for longer.

Furthermore, free radicals can also damage lipids and proteins within the hair fibre, particularly keratin, which weakens the cuticle’s cohesion and makes the lengths more susceptible to breakage and to split ends. By bolstering local antioxidant defences, black cumin oil could therefore help limit this progressive degradation.

Benefit No. 5: Can nigella oil promote hair growth?

The Nigella oil is often linked to beneficial effects on hair growth and the reduction of hair loss, and certain biological mechanisms also point in this direction. Its antioxidant properties could contribute toprotect the hair bulb from oxidative stress, a factor often implicated in the progressive weakening of the follicle and in certain forms of hair loss, thereby contributing to a more favourable environment for hair growth.

Furthermore, the thymoquinone present in black cumin seed oil possesses anti-inflammatory properties that may influence hair loss. Studies have shown that it notably inhibits the expression of the COX-2 enzyme and the synthesis of prostaglandin D2 (PGD2), a molecule identified in high concentrations in areas affected by baldness. Its interaction with the GPR44 receptor within the follicle appears to favour its miniaturisation, namely the progressive transition from so-called terminal hairs (thick and pigmented) to finer, vellus-like hairs. By reducing PGD2 production, black cumin seed oil could thus help to limit hair loss.

Several studies support the idea that black cumin seed powder or black cumin seed oil could promote hair growth. One study evaluated the efficacy of a formulation containing Nigella sativa (10%) incorporated into coconut oil (60%). The researchers tested the formula on groups of rats with a 4 cm² area shaved. At regular intervals (15, 20, 25 and 30 days), they randomly plucked 15 hairs to measure their length and also assessed the total hair weight. The results show a significant increase in hair growth compared to the control groups.

8.89 mm

Mean hair length after four weeks in the oil-treated group.

2.91 mm

Average hair length after four weeks in the control group.

219.49 mg

Mean hair weight after four weeks in the oil-treated group.

150.12 mg

Mean hair weight after four weeks in the control group.

The authors suggest that this difference could reflect an anticipated transition of follicles from the telogen phase to the anagen phase, possibly stimulated by the antioxidants present in the plant extracts. Although these results do not allow any conclusion on the efficacy of black seed oil alone, they reinforce the idea that some of its constituents could, in theory, contribute to supporting hair growth.

These findings are supported by a clinical study involving 20 patients with telogen effluvium, a form of diffuse hair loss linked to a premature transition of follicles into the telogen phase. Over three months, half of the participants applied daily a lotion containing 0.5% nigella oilNigella sativa, while the remaining participants received an identical formulation devoid of nigella extract. The results show a significant increase in hair density and thickness in the patients who received the nigella extract.

90%

Participants in the nigella oil group exhibited an increase in hair density.

30%

Participants in the placebo group exhibited an increase in capillary density.

Although further research remains necessary, especially with a larger sample size, this study reinforces the idea that nigella seed oil may support hair growth.