Nigella sativa oil to protect the skin from the sun’s ultraviolet rays?

Exposure to solar radiation is one of the primary stressors for the skin.

Ultraviolet radiation, particularly UVA, penetrates deeply into the skin tissue and contributes to the excessive production of free radicals. These species damage cellular constituents, disrupt repair mechanisms and promote inflammation, thereby contributing in the long term to skin ageing and certain skin disorders. To mitigate these effects, it is important to protect oneself with sunscreen, whose effectiveness relies on UV filters capable of absorbing and reflecting the sun’s rays before they reach the skin cells.

However, some individuals express reservations regarding sunscreens and wonder about natural alternatives. In this context, certain vegetable oils are sometimes mentioned, among which the nigella oil, extracted from the seeds of Nigella sativa, also known as black cumin. This oil is recognised for its richness in bioactive compounds, notably thymoquinone, and for its antioxidant and anti-inflammatory properties. The question then arises as to whether these characteristics could confer a protective role against the effects of the sun.

An experimental study investigated the role of thymoquinone in UVA-induced skin damage. This work was conducted on HaCaT human keratinocytes, a commonly used cell model. The cells were pre-treated with thymoquinone and then exposed to UVA radiation. The researchers assessed cell viability, apoptosis and markers of oxidative stress, inflammatory cytokines and mitochondrial function.

The results showed that thymoquinone could reduce UVA-induced cytotoxicity in keratinocytes.

Pre-treatment limited the build-up of free radicals, attenuated the inflammatory response and reduced cell apoptosis associated with mitochondrial stress. From a mechanistic perspective, these effects appear to be linked to activation of the NrF2/ARE pathway, a cellular antioxidant defence system, as well as to the inhibition of COX-2 expression, an enzyme involved in inflammatory processes. When this pathway was experimentally blocked, or when COX-2 was activated, the observed protective effects disappeared, suggesting a role for these mechanisms in the cellular response.

These results offer interesting insights into the antioxidant and anti-inflammatory potential of thymoquinone against UVA-induced stress, but they should be interpreted with caution.

This is a study in vitro, carried out on isolated cells, which does not allow a direct protective effect of black seed oil against UV rays in humans to be concluded. Furthermore, the study examined thymoquinone, present in small amounts within the black seed oil (< 1%). It is not certain that the thymoquinone concentration in black seed oil is sufficient to exert this photoprotective effect.

Moreover, a study conducted by MARTINIAKOVA and her team in 2021 investigated the photoprotective capacity of various vegetable oils, including black seed oil, by assessing their sun protection factor (SPF). The authors measured both the SPF in vivo, according to the ISO 24444 standard, in an accredited laboratory in Prague, and the SPF in vitro using the Mansur spectrophotometric method. The values obtained were found to be particularly low.

These findings clearly indicate that Nigella seed oil does not possess a sufficient UV filtering capacity to ensure effective sun protection. By way of comparison, it is generally recommended to use products with an SPF of at least 30 to minimise the effects of UV rays on the skin. Nigella seed oil therefore cannot be considered an alternative to sunscreen filters. However, its antioxidant potential remains relevant. By helping to neutralise part of the oxidative stress induced by sun exposure, Nigella seed oil can be envisaged as an supplement within a skincare routine. It cannot, however, replace sun protection, which alone can effectively block UV rays.

On its own, nigella oil cannot be regarded as a natural sunscreen. However, it may be of interest when used in conjunction with a sun cream, owing to its antioxidant properties.

• MARTINIAKOVÁ S & al. The real UVB photoprotective efficacy of vegetable oils: In vitro and in vivo studies. Photochemical & Photobiological Sciences (2021).

• LI L. & al. Thymoquinone, extract from Nigella sativa seeds, protects human skin keratinocytes against UVA-irradiated oxidative stress, inflammation and mitochondrial dysfunction. Molecular Immunology (2021).

• GUNADI J. W. & al. Role of Nigella sativa L. seed (black cumin) in preventing photoaging (review). Biomedical Reports (2025).