Black seed oil: a natural solution for keratosis pilaris?

The keratosis pilaris is a common, benign skin condition characterised by the appearance of small, rough papules, most often on the arms, thighs and buttocks. It results from a disorder of keratinisation, during which keratin accumulates at the opening of hair follicles, forming horny plugs. This hyperkeratinisation is often associated with dry, sometimes inflamed skin, and may be favoured by genetic or hormonal factors or certain environmental conditions. Although benign, the keratosis pilaris may be perceived as unsightly, prompting the search for solutions to reduce its appearance.

Keratosis pilaris is generally managed with keratolytic agents, such as glycolic acid or lactic acid, capable of eliminating excess keratin.

However, to date, the nigella oil is not associated with keratolytic properties. Its lipid composition and bioactive compounds, such as thymoquinone, instead confer nourishing, antioxidant and anti-inflammatory properties, likely to enhance skin comfort and support the skin barrier. Conversely, no clinical trial has demonstrated a specific effect of nigella oil on keratosis pilaris, nor on the normalisation of follicular keratinisation. It therefore does not target the central mechanism of this skin concern, namely the accumulation of keratin.

That said, a clinical trial has recently highlighted the potential of a nigella extract in another form of keratosis: arsenical keratosis. Although distinct from keratosis pilaris, it shares certain biological mechanisms, notably hyperkeratinisation. In this study involving 32 patients with moderate to severe palmar arsenical keratosis, an ointment containing seed extract of Nigella sativa was applied for 12 weeks (concentration not specified). The results showed a mean reduction of 72.8% in lesion size. The study authors suggest that the nigella extract exerts dose-dependent cytotoxicity on hyperproliferative keratinocytes, which may explain the observed improvement, although this mechanism has not been proven.

These results are interesting, but do not permit any conclusion regarding the efficacy of nigella oil on keratosis pilaris.

Indeed, the study focused on arsenical keratosis which, although similar to keratosis pilaris, is not strictly identical. Moreover, it was not black cumin oil that was tested, but an extract of black cumin seeds formulated in an ointment, and only one small-scale clinical trial is currently available. It is therefore not possible to extrapolate these data to the use of the black cumin seed oil on keratosis pilaris. In practice, for individuals wishing to reduce the appearance of their keratosis pilaris, it is preferable to opt for active ingredients whose efficacy is better documented, notably keratolytic agents.

Finally, it is important to remember that keratosis pilaris is a benign, harmless condition that does not need treating, and whose management is a matter of personal aesthetic preference.

• SCHWARTZ R. A. & al. Keratosis pilaris: A common follicular hyperkeratosis. Pediatric Dermatology (2008).

• GABBIANELLI R. & al. Antioxidant and anti-inflammatory properties of Nigella sativa oil in human pre-adipocytes. Antioxidants (2019).

• MOHAMADI N. & al. The therapeutic effects of Nigella sativa on skin disease: A systematic review and meta-analysis of randomized controlled trials. Evidence-Based Complementary and Alternative Medicine (2022).

• MURRELL D. F. & al. A review of the scoring and assessment of keratosis pilaris. Skin Appendage Disorders (2023).

• NARGIS F. & al. Effect of chloroform extract of Nigella sativa seed in the treatment of palmar arsenical keratosis. Saudi Journal of Medical and Pharmaceutical Sciences (2025).