How to use soybean oil?

Soybean oil is a golden-coloured vegetable oil, easily absorbed by the skin and lightly scented. It is generally obtained by cold pressing soybean seeds, and is widely used in Asian cuisine for the flavour it imparts to dishes, but also for its richness in omega-3, a fatty acid necessary for the development and proper functioning of the body.

Beyond its culinary properties, soybean oil also holds a prominent place in the field of cosmetics. Indeed, this ingredient is present in various formulations (creams, milks, balms, lotions, serums...) and provides numerous benefits to the skin and hair .

The unsaturated fatty acids with which soybean oil is enriched give it nourishing and protective properties for the skin. Its use is therefore particularly recommended for people with dry skin. Indeed, the epidermal barrier of dry skin is fragile as it does not produce enough lipids. Soybean oil can compensate for this deficiency and strengthen the skin barrier by reducing insensible water loss (IWL).

Furthermore, studies have shown that this botanical extract helps to delay skin sagging. In addition to possessing antioxidant properties that combat oxidative stress, soybean oil stimulates the synthesis of collagen and elastin. In doing so, it helps to keep the skin supple and toned. It's also worth noting that the application of soybean oil helps to prevent and reduce hyperpigmentation. Indeed, this compound acts on melanogenesis, the process of melanin synthesis. Finally, soybean oil reduces irritation and redness and soothes the skin thanks to its anti-inflammatory properties.

How to use soybean oil on the skin?

• Pure : Soybean oil can be applied directly to the skin. Take a few drops in the palm of your hand and gently massage the area you wish to nourish. In addition to stimulating blood circulation, these actions will allow the oil to be effectively absorbed by the skin. Soybean oil can also replace your evening moisturiser.

• Diluted in a cream : you can also use soybean oil in synergy with your moisturising cream for the face or body. To do this, take a small amount of cream in the palm of your hand and add one or two drops of soybean oil. You can then apply the treatment by gently massaging and enjoy its nourishing benefits.

Important : the application of pure soybean oil is not recommended for pregnant women and young children as a precautionary measure. Indeed, it may contain minute traces of isoflavones, phytoestrogens that could potentially interact with the hormonal system.

Thesoybean oil can also be used in the haircare field where it is particularly appreciated by people with dry, thin or brittle hair. Indeed, the saturated fatty acids found in soybean oil have a chemical structure similar to that of the lipids that make up the hair cuticle, allowing them to integrate and strengthen it. The hair fibres then gain in impermeability and the hair becomes silkier and shinier. Moreover, the antioxidant properties of soybean oil allow it to protect the fibres from oxidative stress, a factor that weakens the hair follicles, alters the natural colour of the hair and can cause hair loss.

How to apply soybean oil to the hair?

• In an oil bath : Performing one or two vegetable oil baths per week can deeply nourish the hair fibres and restore their shine. Apply a few drops of soybean oil to each of your strands, starting from the mid-lengths and going down to the tips. Leave it on for about fifteen minutes before shampooing.

• As a scalp mask : Soybean oil can also be applied to the scalp to soothe redness and irritation. Pour a few drops and gently massage to allow the soybean oil to penetrate. Then wait 30 minutes before shampooing. If you feel that your scalp is still greasy after this cleaning step, do not hesitate to shampoo a second time.

Finally, soybean oil is widely used for its gastronomic properties and its pronounced flavour. Its consumption is also recommended for maintaining good cardiovascular health as it helps to lower LDL cholesterol levels, also known as "bad cholesterol". From a biological perspective, it is the polyunsaturated fatty acids present in soybean oil that are at work, increasing the activity of LDL receptors in the liver. This action allows for a more efficient elimination of LDL cholesterol.

Furthermore, while soy-based products have benefits for the body, ANSES recommends not consuming more than one soy-based product per day. Indeed, it is advised not to exceed 1 mg of isoflavones/kg/day, which equates to 60 mg of isoflavones for a person weighing 60 kilos. A soy-based product providing about 25 to 40 mg of isoflavones, it is understandable that it is recommended not to exceed one product per day.

Key Point : As is often the case, the boundary between benefits for the body and health risks lies in the consumed dose, which recalls the principle of toxicology stated by the physician-philosopher Paracelsus in the 16th century: "The dose makes the poison".

• BUCK D. Antioxidants in soya oil. Journal of the American Oil Chemists’ Society (1981).

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

• PLANCHENAULT N. & al. Les aliments au soja : consommation en France, qualités nutritionnelles et données scientifiques récentes sur la santé. Oilseeds & fats, Crops and lipids (2016).