What It Is Made Of
The base is a fatty acid profile: mostly oleic and stearic acid, with smaller amounts of linoleic and palmitic. The ratio between them decides whether a given batch feels softer and oilier or firmer and more waxy.
The unsaponifiable fraction
This is the part that sets shea apart from most plant oils. It contains vitamin E, phytosterols and triterpene alcohols, and it is considerably larger than in ordinary oils. It is credited with the more pronounced softening and soothing feel.
How It Works on Skin and Hair
Shea butter works mainly as an occlusive: it forms a thin layer on the surface that slows water evaporation. Which is why it performs best on damp skin, over a humectant, rather than on its own over a dry surface. There is more on the mechanism in our article on the skin barrier.
On hair
On hair the effect is similar: it seals moisture into the strand and reduces friction between hairs. Curly and very dry hair benefit most, while fine hair weighs down easily, so there it goes on the ends only and in small amounts.
Refined or Unrefined
Unrefined retains more of its natural components but has a distinctive nutty smell and a grainier texture. Refined is odourless and smoother, though some of the accompanying compounds are lost in processing. For a cosmetic formula refined is usually more predictable; for home use, unrefined is a matter of preference.
Who It Suits
Dry and very dry skin, skin during the heating season, hands, elbows, feet and lips. On oily, congestion-prone facial skin, approach with care: it is a heavy butter and for some people it can contribute to blocked pores. For body use that limitation barely applies.
How to Use It
Comedogenicity: The Contested Question
Shea butter is often described as pore-clogging. The truth is more nuanced: comedogenicity scales rest on old research done on animal models using pure oils at concentrations rarely found in a finished product.
In practice the response is individual. Some people with oily skin tolerate it well in a light cream; others get congestion from a small amount. If your skin is congestion-prone, patch test before putting it on your whole face.
Storage and Texture
Shea melts at body temperature and sets again as it cools. If it has melted and then set quickly, it can turn grainy. That does not mean it has spoiled: the grainy texture is fatty acid crystallisation and it smooths out when warmed between your palms.
Store it somewhere cool and out of direct light. Its shelf life is relatively long thanks to the vitamin E content, which also acts as a natural antioxidant within the butter itself.
On slightly damp skin, as the last step. Applied first, it seals dry skin in and achieves little. A small amount warmed between your palms spreads far more easily than cold butter straight from the jar.
