The modern definition of a wax is that it is not a glyceride. Glycerides are fats which are closely related to waxes but waxes are harder, less greasy, more brittle and very resistant to moisture, oxidisation and microbial attack.1 The melting points of waxes vary widely depending on their unique composition and chain lengths. Beeswax, candelilla, carnauba and polyethylene waxes are some of the more commonly used types in cosmetic formulations. They provide structure to sticks, barrier function to balms and creams and add thickening and waterproofing properties to mascara.
There is confusion in the identification of plant lipids as waxes, butters or oils. Waxes are composed primarily of long-chain esters that are solid at room temperature but when differentiating between oils and butters, lines become blurred. Identification depends on the solidification point of the plant lipid, which varies as a result of the exact lipid composition.2
Each wax has its own unique set of attributes and it is the job of the formulator to combine them at carefully selected ratios to achieve optimal cosmetic performance. Usually a wax will be softened by combining it with a compatible oil. Tables 1 & 2 show some useful classifications and melt points.
Fats (and butters fall into this category) are soft, semi-solid organic compounds. The difference between fats and oils is that fats are solid at ambient temperatures – they have a higher melt point than oils.3 Butters are natural fats and are extracted from various plants seeds or roots and consist of solid or semi-solid fat oils and fatty acids. All make excellent emollients, softeners and protecting agents but each has its own unique properties – be it anti-inflammatory, soothing, moisturising or antioxidant.
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