Huile de soja et protection solaire.

Soybean oil for UV protection?

Endowed with numerous properties for the skin and hair, soybean oil is used in many cosmetic treatments. Some people even consider it as a natural sun protection. Can this vegetable oil truly be used to protect oneself from UV rays?

Summary
Published January 30, 2024, updated on October 4, 2024, by Pauline, Head of Scientific Communication — 4 min read

What are the effects of UV rays and sunlight on the skin?

The sun is both beneficial for health and harmful in case of prolonged exposure. Indeed, its rays allow to stimulate the secretion of vitamin D, a pro-hormone that strengthens the immune system, but also to lower blood pressure while ensuring a chrono-biological balance.

However, overexposure leads to adverse effects on the skin. UV rays promote hyperpigmentation, skin sagging, but can also cause sunburns or skin cancers. These issues are caused by the excessive generation of free radicals, unstable molecules that distort the fatty acids of cell membranes and attack DNA and certain functional proteins such as collagen.

Soybean oil to protect skin from UV rays?

Thesoybean vegetable oil, also known as "Glycine Soja Oil", appears as a slightly yellowish liquid, very penetrating, creamy, and lightly scented. This oil, typically extracted by cold pressing soybean seeds, is highly valued in cosmetics and is used as a skin conditioning agent, emollient, moisturizer, and antioxidant. The properties of the soybean vegetable oil come from its numerous bio-active components.

This natural ingredient also has a photoprotective action. However, it should be noted that this is very limited. Indeed, soybean oil has a SPF (Sun Protection Factor), also known as SPF, of 10. The SPF is the index measuring a skincare product's ability to block UV rays, and thus to protect the skin from their impact. The higher this index, the greater the photoprotective power. In practical terms, the SPF corresponds to the ratio between the exposure time needed to induce a sunburn with and without skincare.

Generally, a sunscreen is considered effective when its SPF (Sun Protection Factor) is 15 or higher. Therefore, applying soybean oil alone is not sufficient to protect against the sun's UV rays, despite the photoprotective properties of this ingredient. Moreover, this vegetable oil is not officially recognized and listed as a sunscreen filter by European regulations. Consequently, its sole use in a sunscreen product to provide a sun protection factor is not in compliance with current regulations.

However, the incorporation of soybean oil remains beneficial in sun care products with approved ultraviolet filters due to its antioxidant properties. These properties allow it to partially protect the skin by helping it combat the accelerated aging caused by free radicals.

Protecting Yourself from the Sun: The Right Habits to Adopt.

To effectively protect oneself from the sun and its dangers, it is recommended to adhere to certain precautionary principles, the first of which is toavoid exposure between 12pm and 4pm, the hours of the day when UV rays are most intense. It is also essential to apply a broad-spectrum sunscreen with a good SPF rating and in sufficient quantity, in order to be well protected.

Finally, dressing appropriately is the best way to protect oneself from the sun's UV rays. The most effective ensemble includes a long-sleeved t-shirt or shirt, long pants or a skirt made of canvas, a wide-brimmed hat, and sunglasses with protective lenses.

Sources

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

  • MURTAZA G. & al. Dermatological and cosmeceutical benefits of Glycine max (soybean) and its active components. Acta Polonia Pharmaceutica (2015).

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