Isobutyl Stearate

What Is It?

The stearate esters (Butyl Stearate, Cetyl Stearate, Isocetyl Stearate, Isopropyl Stearate, Myristyl Stearate, Ethylhexyl Stearate, Isobutyl Stearate) are oily liquids or waxy solids. Ethylhexyl Stearate may also be called Octyl Stearate. In cosmetics and personal care products, stearate esters are used most frequently in the formulation of eye makeup, skin makeup, lipstick and skin care products.

Why Is It Used?

Stearate esters act primarily as lubricants on the skin’s surface, which gives the skin a soft and smooth appearance. Butyl Stearate also decreases the thickness of lipsticks, thereby lessening the drag on lips, and imparts water repelling characteristics to nail polishes. Butyl Stearate and Isopropyl Stearate dry to form a thin coating on the skin. Isocetyl Stearate can also be used to dissolve other substances, usually liquids.

Scientific Facts

The stearate esters are prepared by reacting stearic acid with the appropriate alcoholAlcohols are a large class of important cosmetic ingredients but only ethanol needs to be denatured to prevent it from being redirected from cosmetic applications to alcoholic beverages. (butyl, cetyl, isobutyl, isocetyl, isopropyl, myristyl or ethylhexyl alcohol). Stearate esters have the unique properties of low viscosity and an oily nature, which results in a nongreasy, hydrophobic film when applied to the skin or lips. Stearic acid is found in animal and vegetable fats.

Safety Information

The Food and Drug Administration (FDA) includes Butyl Stearate on its list as a flavoring agentIngredients that impart a flavor or a taste to a product. allowed to be directly added to food. Butyl Stearate is also as an approved indirect food additiveIndirect food additives are additives that may become part of the food in trace amounts due to its packaging, storage or other handling. For example, minute amounts of packaging substances may find their way into foods during storage. and can be used as a component of adhesives. The safety of the stearate esterAn organic compound formed by the reaction of an acid with an alcohol. ingredients has been assessed by the Cosmetic Ingredient ReviewThe Cosmetic Ingredient Review (CIR) was established in 1976 as an independent safety review program for cosmetic ingredients. The CIR Expert Panel consists of independent experts in dermatology, toxicology, pharmacolgy and veterinary medicine. The CIR includes participation by the U.S. Food & Drug Administration and the Consumer Federation of America. (CIR) Expert Panel. The CIR Expert Panel evaluated scientific data and concluded that Butyl, Cetyl, Isobutyl, Isocetyl, Isopropyl, Myristyl and Ethylhexyl Stearate were safe as cosmetic ingredients. In 2003, as part of the scheduled re-evaluation of ingredients, the CIR Expert Panel considered available new data on the stearate esters and reaffirmed the above conclusion.

CIR Safety Review: The CIR Expert Panel noted that the safety of the stearate esters has been assessed in a number of studies. They had low acute oral toxicity and were essentially nonirritating to the eyes when tested at and above use concentrations. At cosmetic use concentrations, the stearate esters were, at most, minimally irritating to skin. In clinical studies, the stearate esters and cosmetics and personal care products containing them, were at most minimally to mildly irritating, essentially nonsensitizing, nonphototoxic and nonphotosensitizing.

The CIR Expert Panel indicated that comedogenicityRefers to the chance that an ingredient or product will cause pores in the skin to clog. This may result in blackheads or whiteheads, officially called comedones. should be considered when using the stearate ester ingredients in cosmetic formulations.

Link to FDA Code of Federal Regulations for Butyl Stearate

If they are derived from plants, the stearate esters may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European UnionUnder the general provisions of the cosmetics regulation of the EU, ingredients appearing on the following function-specific annexes must comply with the listed restrictions and/or specifications: colorants (Annex IV), preservatives (Annex V), UV filters (Annex VI) and other ingredients with specific concentration limits and/or other restrictions (Annex III). Ingredients specifically prohibited from use in cosmetic products are listed in Annex II. Other ingredients listed in the EU cosmetic ingredient database (CosIng) may be used without restrictions..

Ingredients of animal origin must comply with European Union animal by-products regulations.

Link to the EU Cosmetic Regulation:
http://europa.eu/legislation_summaries/consumers/product_labelling_and_p…

The Joint FAO/WHO Expert Committee on Food Additives has not allocated an Acceptable Daily Intake for Butyl Stearate. The Committee believes no safety concern is present at current levels of intake when Butyl Stearate is used as a flavoring agent.
http://www.inchem.org/documents/jecfa/jeceval/jec_288.htm

More Scientific Information

The stearate esters are esters of stearic acid and an alcohol. Due to the grade of stearic acid and the alcohols used as starting materials, the commercially available stearate esters are often mixtures of various esters. The name indicates the ester at the highest concentration. In cosmetics and personal care products, the stearate esters function mainly as skin conditioning agents – emollients. Butyl Stearate also functions in lipsticks as a viscosity decreasing agentSubstances that decrease the thickness of liquid cosmetic products and a color-suspending agent. In nail polishes, Butyl Stearate may be used as a water-repelling plasticizerMaterials that soften synthetic polymers by reducing brittleness and cracking.. In hand creams and lotions, Butyl and Isopropyl Stearate function as spreading agents. Isopropyl Stearate also serves to increase the gelatin characteristics of hand product formulations. Isocetyl Stearate is used in cosmetics and personal care products as a lubricant and solventSubstances, usually liquids, that are used to dissolve other substances..

Resources

Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging: http://www.fda.gov/Food/IngredientsPackagingLabeling/default.htm

Food Contact Substances: http://www.fda.gov/Food/IngredientsPackagingLabeling/PackagingFCS/defaul…

Substances Generally Recognized As Safe (GRAS“GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.): http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/default.htm

Search the Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm

EU Cosmetics Inventory http://ec.europa.eu/consumers/cosmetics/cosing/