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Is castor oil effective as a natural sun protection for the skin?

Endowed with numerous properties for the skin and hair, castor oil is incorporated into various cosmetic treatments. Some people even consider it as a natural sun protection. What is the actual effect of this vegetable oil on UV rays?

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

What is castor oil?

Known by its INCI name Ricinus Communis (Castor) Seed Oil, thecastor oil is a fatty vegetable oil obtained by cold pressing of the castor seed. Originating from Africa, this shrub has gradually acclimatised to the Mediterranean region. Castor oil is generally colourless to light yellow and has a viscous texture. It is predominantly composed ofricinoleic acid (about 85%), but also contains other fatty acids as well as vitamin E.

Castor oil has numerous benefits for the skin and hair, including nourishing and strengthening properties. It is indeed recognised for its roles in fortifying and thickening eyelashes, eyebrows and hair. Moreover, ricinoleic acid is an antimicrobial agent capable of inhibiting the proliferation of certain bacteria, including Cutibacterium acnes, which is involved in the development of acne.

What about the photoprotective properties of castor oil?

The SPF (Sun Protection Factor), also known as SPF (Sunburn Protection Factor) in English or PI (Protection Index), is the index representing the level of sun protection of a skincare product. It measures its ability to block UV rays responsible for sunburn. The higher the SPF, the greater the photoprotection power. The numbers indicated after the SPF mention correspond to the ratio between the exposure time needed to induce a sunburn with and without cream.

Castor oil has a protection factor equal to 6, which is relatively low. It is also possible to interpret this differently with SPF. A factor of 6 means that castor oil blocks approximately 85% of UV rays. At first glance, this may seem satisfactory but the remaining 15% is significant enough to cause sunburn.

Is castor oil sufficient for UV protection?

Despite its numerous benefits, castor oil does not replace sun care. It lacks effectiveness due to its low sun protection factor. It's worth noting that a sun care product is generally considered effective when its SPF is equal to or greater than 15. Moreover, castor oil is not among the 27 UV filters recognised by European regulations.

Thus, in order to protect oneself during prolonged exposure to the sun, it is recommended to use broad-spectrum sun care products, that is, protecting against both UVA and UVB rays. Today, there is a wide variety of formulations (creams, milks, oils, sticks, sprays...), which allow each skin type to find its perfect match. To ensure maximum protection, we advise you to generously apply sun care products and to ensure no area is neglected (ears, tip of the nose...).

Sources

  • DOWDY J. C. & al. Simplified method to substantiate SPF labeling for sunscreen products. Photodermatology, Photoimmunology and Photomedecine (2003).

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

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