SHEA BUTTER

2. Shea butter

Shea butter to nourish dry and dehydrated skin.

The most obvious benefit, of course, is its hydrating and nourishing properties. Its qualities are linked to its high fatty acid content - and thanks to the types of fatty acids it contains (namely linoleic acid and oleic acid), it tends to be non-greasy and easily absorbed.

In fact, the fatty acids in shea butter fall into 3 categories, including monounsaturated fatty acids, polyunsaturated fatty acids and saturated fatty acids. These molecules contribute to hydration by strengthening the skin's protective barrier, itself made up of fatty acids. As a reminder, the hydration of the skin is maintained by the presence of the hydrolipidic film which prevents evaporation and maintains the hygroscopic molecules in the cells.

This plant-based butter has been shown to seal moisture into the skin and protect the skin barrier. One study even suggests that it has topical effects similar to those of ceramides, the polar lipids naturally present in the epidermis and responsible for sealing the skin barrier.

Shea butter and its components are also called phytoceramides.

The fatty acids that make up shea butter.

Here are the main fatty acids present in shea butter .

• 40 to 50% oleic acid or omega-9.

This monounsaturated fatty acid is a lipid which is part of the composition of sebum, a

substance naturally secreted by the body to compensate for dryness of the skin and hair. It stimulates the production of sebum by the sebaceous glands.

• 36 to 50% stearic acid.

The National Library of Medicine (NLM) defines stearic acid as a long-chain saturated fatty acid. The long chain is made up of 18 carbon atoms. In skin care, stearic acid is recognized for its emollient, nourishing and protective (film-forming) properties.

• 4 to 8% linoleic acid or omega-6.

This category of fatty acids is called essential because it is not synthesized by the body.

Omega 6 contributes to the cell renewal process. When applied to the skin, they help fight the signs of aging and promote healing. They also soothe inflammatory reactions and are beneficial for sensitive skin suffering from tightness and irritation.

• 3 to 8% palmitic acid.

Saturated fatty acids, like palmitic acid, have emollient properties, meaning they promote hydration of skin and hair cells. They thus give flexibility and softness.

Sources:

• LEUNG TF & al. Patient acceptability, efficacy, and skin biophysiology of a cream and cleanser containing lipid complex with shea butter extract versus a ceramide product for eczema. Hong Kong Medical Journal (2015).

• SANTIAGO JL & al. AnS-inflammatory and skin barrier repair effects of topical application of some plant oils. International Journal of Molecular Sciences (2018).