Huile de nigelle et taches brunes.

Black seed oil to combat dark spots?

Black seed oil, also known as black cumin oil, is a vegetable oil with numerous benefits. Rich in fatty acids and active ingredients, including thymoquinone, it protects against and combats various skin issues. What are the effects of black seed oil on brown spots?

Summary
Published June 9, 2023, updated on October 4, 2024, by Pauline, Chemical Engineer — 5 min read

How are brown spots formed?

The pigment spots are the result of an accumulation of melanin in the skin. As a reminder, melanin is a brown pigment that plays a protective role against UV rays. However, in the case of overproduction, pigment spots impacting the uniformity of the complexion appear. Depending on their origin, these are classified into three distinct categories.

  • The sun spots caused by prolonged and repeated exposure to the sun's UV rays.

    The primary cause of the appearance of brown spots is exposure to the sun's UV rays. Indeed, these rays activate the melanogenesisprocess, which is the synthesis of melanin. Sun spots gradually form throughout life, as sun exposure is repeated. That's why it's important to apply a sunscreendaily. Tobacco or pollution can also play a role in their appearance, as these elements generate oxidative stress in cells and accelerate skin aging.

  • The pregnancy mask is related to hormonal changes.

    Pregnancy is not without hormonal consequences. It notably leads to a significant increase in the levels of estrogen and progesterone in the body, hormones capable of activating melanogenesis. Also known as melasma, the pregnancy mask can also appear following the use of a contraceptive pill or hormone replacement therapy.

  • Thepost-inflammatory hyperpigmentation.

    Brown spots can also form as a result of skin inflammation or lesions. Indeed, during inflammation (acne, burn, injury...), pro-inflammatory cytokines stimulate the activity of melanocytes.

What are the effects of black seed oil on brown spots?

Theblack seed oil is a natural ingredient derived from the seeds of black cumin. Versatile, it is used for both its gastronomic and cosmetic properties. It can be found in the INCI list of many skin care and hair care products under the name Nigella Sativa Seed Oil due to its numerous virtues: anti-inflammatory, antioxidant, healing, moisturizing... Sometimes, black seed oil is also attributed with a lightening action.

Nevertheless, no scientific study has to date shown that this ingredient has effects on brown spots. On the contrary, there are reasons to believe that black seed oil could instead be useful in cases of hypopigmentation or vitiligo. In an in vitro study, researchers incubated common wall lizard skin in solutions with different concentrations of thymoquinone, one of the active ingredients in black seed oil. This species of lizard was chosen because its pigment response is uniform.

After incubation for about ten minutes, a dispersion of melanophores was observed. Melanophores are cells specific to certain amphibians and birds that can be considered analogous to mammalian melanocytes. However, unlike melanocytes, melanophores do not synthesize melanin, they only store it. Melanophores can be dispersed in the cytoplasm, which then darkens, or be gathered into clusters (clear cytoplasm). Thus, the dispersion of melanophores observed in the study is synonymous with a darkening of the skin.

As of now, black seed oil cannot be considered as a lightening ingredient and, on the contrary, seems to have a potential darkening effect. If you wish to lighten your brown spots, we would rather recommend the vitamin C, the azelaic acid, the arbutin acid, the licorice extract, the tranexamic acid or even the glycolic acid.

Sources

  • MEITEI K. & al. Nigella sativa seed extract and its bioactive compound thymoquinone: the new melanogens causing hyperpigmentation in the wall lizard melanophores. The journal of pharmacy and pharmacology (2011).

  • KIM B. & al. Black Cumin ( Nigella sativa L.): A Comprehensive Review on Phytochemistry, Health Benefits, Molecular Pharmacology, and Safety. Nutrients (2021).

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