What Is Shea Butter, What Does It Do? Properties and the Pore Question

The botanical name of the shea tree today is Vitellaria paradoxa, but in ingredient lists you see its old name, Butyrospermum Parkii. The fat is extracted from kernels collected in countries such as Ghana and Burkina Faso. In creams it acts as an emollient, smoothing roughness, and its thick consistency leaves a film on the surface. It does not add water to the skin; it tries to limit the escape of the water already present. So applying it to damp skin is more sensible than applying it to dry skin.

What is inside shea butter, and why is it solid?

The difference from liquid oils is the high proportion of saturated fatty acids such as stearic acid. These fatty acids stay solid at room temperature and soften when applied, with body heat. In a sample measurement the distribution was as follows:

Proportions vary with the tree and the production method. Among the components that make shea notable, triterpene esters were measured at most at about 3,6% in the kernel. The anti-inflammatory effect also comes largely from macrophage cultures. The result seen in a cell dish does not mean it will produce the same result on the skin.

What data are there on dry skin and eczema?

The film-forming property of thick fats is a known feature, so reducing dryness is an expected effect. Still, there is little study directly measuring how much pure shea reduces water loss. If you have eczema, do not treat it as a medicine; the treatment decision rests with your physician. For a daily routine, you can look at the dry skin care article.

Does shea butter clog pores?

Honest answer: it is not known for certain. The pore-clogging scores of 0-5 circulating online rely on old rabbit ear tests. The rabbit ear does not behave like human skin; the test may detect irritation rather than the outcome for the finished product. There is also no widely accepted standard test for a claim that it does not clog pores. We do not know of a good study testing shea on the human face, so both "clogs" and "does not clog" remain too strong a claim.

If you are prone to breakouts, start in a small area rather than applying pure shea to the whole face. Comedone formation can take several weeks; clean first days do not determine the result. If problems arise on combination or oily skin, keeping shea on dry areas such as elbows, heels and hands is an easier way.

Raw shea or refined shea?

The claim that "raw is better" is only half true. Refining does reduce the amounts of tocopherols, sterols and phenols, but the quality of raw oil also varies a lot from batch to batch. In a preprint analysis, still at the pre-publication stage, in which 37 traditional samples from Burkina Faso were examined, the ranges were very wide:

So raw butter may carry more minor components, but it can also be a spoiled batch. Do not apply butter that smells sour or rancid to the skin; keep it in a cool place with a closed lid.

Does it protect from the sun, and does it cause allergy?

• Sun: In the laboratory, shea's light absorption peak was measured around 280 nm, that is, at the lower limit of UVB. This does not make it a sunscreen. When going outside, apply a broad-spectrum product of at least SPF 30, and renew it every 2 hours and after sweating or swimming.
• Nut allergy: In one laboratory study, no soluble protein binding IgE antibodies was detected in shea butter. Reassuring, but it is a single study. If you have a serious nut allergy, ask your doctor.
• Newborns and open wounds: A case has been published of a 10-day-old baby with an umbilical infection and bacteria in the blood after shea was applied to the umbilical stump. Do not apply non-sterile butter to a baby's umbilicus or to an open wound.
• Test: Test a new product on the inner arm or elbow crease, twice a day, for 7-10 days. If redness or itching appears, stop.