Jaunissement des cheveux par huile de ricin.

Does castor oil cause hair to turn yellow?

A natural hair care product with multiple benefits, castor oil is incorporated into many cosmetic treatments. It is particularly known for its stimulating effect on hair growth. However, despite the benefits it provides, castor vegetable oil is often accused of having a yellowing effect on hair. Unfounded belief or proven fact?

Summary
Published May 20, 2023, updated on October 4, 2024, by Pauline, Head of Scientific Communication — 4 min read

The benefits of castor oil on hair.

Thecastor oil (INCI: Ricinus Communis (Castor) Seed Oil) is one of the most commonly used vegetable oils in hair care. It is derived from the cold pressing of the seeds of the common castor (Ricinus communis), a shrub mainly cultivated in China, India and Brazil. From an organoleptic point of view, castor oil presents itself as a thick or even viscous liquid and is renowned for its nourishing and strengthening virtues, which come from the saturated fatty acids it contains.

Thecastor oil is also valued for its ability to limit hair loss. Scientific studies have indeed demonstrated that ricinoleic acid, present in large quantities in this oil, inhibits the action of prostaglandin D2 (PGD2), a protein involved in androgenetic alopecia issues.

Castor Oil and Hair Care: A Potential Yellowing?

The numerous benefits of castor oil as a hair treatment are well established. However, it is also criticised for a few negative effects, such as its viscous consistency and its yellowing effect. It should be noted at this point that this disadvantage has not yet been scientifically demonstrated. Only a few testimonials mention the yellowing action of castor oil, when it is used in large quantities. It can be assumed that this depends on the natural pigmentation of the hair, with some being more sensitive to this phenomenon.

Furthermore, it has been observed that individuals who notice a yellowing of their hair following the use of castor oil often have coloured hair. It is well-known that hair dyes can lead to a weakening of the hair fibre. Therefore, it can be inferred that damaged hair is more prone to yellowing. The quality and quantity of the castor oil used can also be implicated.

How to avoid the yellowing effect of castor oil on hair?

Although there is no scientific evidence to support the claim that castor oil can cause hair yellowing, here are some tips to continue enjoying its benefits for hair application.

  • Moderate the amount of castor oil applied.

    Castor oil is very rich and oily, and there is no need to apply it in large amounts. On the contrary, this could weigh down your hair and potentially cause it to yellow. Therefore, whether you use it on your roots to stimulate hair growth or on your lengths to nourish them, apply only a few drops.

  • Performing a shampoo after the application of castor oil.

    According to some testimonies, it appears that leaving a product on for too long or neglecting to shampoo afterwards can promote hair yellowing. To avoid this phenomenon, do not hesitate to thoroughly focus on the areas where you have applied castor oil during your shampooing and rinse abundantly.

  • Avoid castor oil when you have coloured hair.

    Since a link appears to exist between hair yellowing and colouring, it may be prudent to use hair care treatments other than castor oil if you have coloured hair.

  • Pay attention to the quality of the castor oil used.

    Finally, to limit the risk of your hair turning yellow, it is recommended to use high-quality castor oil, cold-pressed and filtered to avoid any impurities.

Sources

  • FONG P. & al. In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss. Journal of Ethnopharmacology (2015).

  • MARWAT S. K. & al. Review - Ricinus communis - ethnomedicinal uses and pharmacological activities. Pakistan Journal of Pharmaceutical Sciences (2017).

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