Shea Butter, Explained: What the CIR Safety Review Found on Fatty Acid Ranges, Use Levels Up to 100 Percent and Why Shea Nut and Seedcake Extracts Are Different
Shea butter is one of the most common rich ingredients in body butters, lip balms and hand creams, and it is often described in vague, glowing terms. This guide sticks to what a primary source says. The Cosmetic Ingredient Review (CIR), the US industry-funded expert panel that reviews cosmetic ingredient safety, assessed 13 shea-derived ingredients. We read its report, which we found as a March 2017 draft final report, and summarize what it measured, at what concentrations and what it did not conclude.
What shea butter is
Shea butter is the fat obtained from the fruit of the shea tree, listed on labels as Butyrospermum parkii (shea) butter. The report notes that the accepted botanical name is Vitellaria paradoxa. The report's general scheme shows the nut boiled to give shea oil and hexane extraction to give the butter, while acetone fractionation of the oil gives a liquid shea oleine and a solid shea stearine. In the International Cosmetic Ingredient Dictionary, shea butter is listed as a skin-conditioning agent and occlusive, meaning it sits on the surface and slows water loss.
What is in it: mostly stearic and oleic fat
The report's composition table gives total fatty acid ranges for shea butter of 25.6 to 50.2 percent stearic acid, 37.1 to 62.1 percent oleic acid and 0.6 to 10.8 percent linoleic acid. Stearic acid makes the butter firm at room temperature, and oleic acid is the softer part. A study of 36 samples from seven countries, cited in the report, found that the shea kernels held 30 to 54 percent fat and that 2 to 12 percent of that fat was non-saponifiable, the fraction that soap-making does not turn into soap. Ranges this wide mean that two jars labelled shea butter are not identical.
The unsaponifiable fraction and tocopherols
The non-saponifiable part holds triterpene alcohols such as alpha-amyrin, beta-amyrin and lupeol, many of them as cinnamic acid esters. In the 36-sample study, triterpene esters ranged from 0.5 to 6.5 percent. The report also gives mean tocopherols of about 208 micrograms per gram across 102 butter samples, of which alpha-tocopherol was 112. The report does not claim any skin benefit for these compounds. They are composition data, and the amounts differ by origin and climate.
How much is used: from traces up to 100 percent
According to 2017 data in the report, shea butter had 5,447 reported uses in FDA's voluntary registration database, more than any other shea ingredient, with 4,146 of them in leave-on products. The industry survey listed a maximum use concentration of up to 100 percent in moisturizers, up to 8 percent in eye-area products and up to 9.4 percent in products that may be incidentally ingested, such as lip products. A pure butter in a tin and a lotion that lists shea butter near the end of the label are very different products.
What the safety testing covered
In the report, human repeat insult patch tests with products containing shea butter were negative at concentrations up to 60 percent, and in-use studies of lip gloss and massage oils found no irritation at up to 45 percent. A guinea pig study used 75 percent for induction. The panel noted that it had no sensitization data at 100 percent, but because of the other data, its clinical experience and the lack of adverse event reports, it was not concerned. Its conclusion: nine butter, oil and glyceride ingredients are safe as used in the present practices of use and concentration described in the report.
Where the conclusion stops
For four other shea ingredients, nut extract, nut shell powder, seedcake extract and hydrolyzed seedcake extract, the panel said the data were insufficient to determine safety, citing missing manufacturing, composition and sensitization data. That is a gap in data, not a finding of harm. The report also warns that a botanical is a complex mixture and that several botanicals in one formula can add up a single constituent. We did not find comedogenicity data for shea butter in the report, so any claim that it does or does not clog pores goes beyond what this source supports. Compare it with cocoa butter, which has a different regulatory footing, and with jojoba oil, a liquid wax ester rather than a fat.
Regulation and reading the label
The report states that shea ingredients are not restricted under EU cosmetics rules, and that shea oil is generally recognized as safe as a US direct food additive under 21 CFR 184.1702. On a label, look for the plain butter name, since extracts and nut-derived ingredients are different materials. If you are sensitive to fragrance, remember that rich butters are often paired with perfume. Anyone with a tree-nut allergy should ask an allergist before use, because this guide cannot assess that. For another occlusive that has its own data, see lanolin.
Short version
The CIR panel judged shea butter, shea oil and several related ingredients safe as used, with patch tests negative up to 60 percent and in-use studies up to 45 percent, while four nut and seedcake ingredients lacked enough data. Composition varies widely, and the report offers no comedogenicity numbers. Test any new product first using our patch-test method. This article is educational, not medical advice: ask a dermatologist about eczema, persistent dryness or any skin problem.
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