Shea Butter

Shea butter is a soft, ivory-coloured plant fat pressed from the kernels of the shea tree, which grows wild across the dry savannah belt of West and Central Africa. On an ingredients list it appears under its INCI name Butyrospermum Parkii (Shea) Butter — a nod to the tree's former botanical name. The currently accepted name is Vitellaria paradoxa, so you will see both used.

The nuts are gathered, dried and cracked, and the kernels are then either hand-churned in water in the traditional way or mechanically pressed and refined. That processing route matters. Unrefined shea butter keeps its faintly nutty, smoky scent and a yellow-to-greenish tint; refined grades are paler, close to odourless and more consistent batch to batch, though some of the minor plant compounds are lost along the way.

Chemically it is mostly triglycerides built from five fatty acids — oleic and stearic acid make up the bulk, with smaller amounts of linoleic, palmitic and arachidic acid. What sets shea apart from most vegetable oils is its unusually large unsaponifiable fraction: the portion that is not fat at all, containing triterpene alcohols, phytosterols, tocopherols (vitamin E) and phenolic antioxidants, including catechins such as epicatechin gallate, gallocatechin and epigallocatechin, alongside quercetin.

In cosmetics it is used as an emollient and texture-builder in body butters, hand and foot balms, lip products, rich face creams and hair conditioners, and it is a mainstay of formulas aimed at dry, rough or tight-feeling skin.

Shea butter does its work at the surface of the skin, and it does two things at once.

First, it acts as an occlusive. Solid at room temperature, it softens at skin temperature and spreads into a thin, water-resistant film across the outermost layer. That film slows the rate at which water evaporates from the surface — what formulators call transepidermal water loss — so the moisture already in your skin, plus anything humectant you applied underneath, stays put for longer. Skin holding onto more water looks plumper and reflects light more evenly, which is why rough patches look smoother rather than simply feeling greasy.

Second, it acts as an emollient. Its fatty acids slot in between the loose, lifted flakes of a dry surface, filling the gaps and softening the texture you feel under your fingertips.

That unsaponifiable fraction gives shea measurable antioxidant activity in laboratory testing. That antioxidant activity helps the butter itself resist going rancid. It is worth being straight about the limits here: this has been measured in the laboratory, not on skin, and reviews of plant oils in dermatology have looked at whether shea does anything for the skin barrier and treat the question as open — most of that work has been done in cell models rather than on people.

Shea butter works best as a sealing step, not a starting point.

• Apply to slightly damp skin, straight after cleansing or bathing, so there is water to seal in.
• Warm a small amount between your fingertips first. It spreads much further than it looks like it will — most people use far too much.
• Put it last. Layer it over watery serums and humectants such as glycerin or hyaluronic acid; anything applied on top will struggle to get through.
• Match the format to the area. Neat butter suits hands, feet, elbows and lips. On the face, especially if your skin is oily or blemish-prone, a lotion or cream containing shea is more comfortable.
• Twice daily is fine. It is anhydrous, so there is no pH requirement and it does not interfere with retinoids, vitamin C or exfoliating acids. If an active feels too strong, apply a plain moisturiser before it rather than sealing shea over the top, which can increase how much of it gets through.
• Store it somewhere cool. Repeated melting and resetting makes it grainy — texture, not spoilage.