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Formulating with Naturals—Hair Care
By: Art Georgalas, Georgalas Endeavors LLC
Posted: April 5, 2011, from the April 2011 issue of Cosmetics & Toiletries.
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These two product development paradigms are, in a sense, arbitrary distinctions, with the lines blurred for many products but they do provide some direction as to the strategies for both goal-directed formulating on the front end and claim substantiation testing on the back end. By examining traditional hair care categories for their critical performance ingredients, formulators can determine what functionality is potentially available from the use of natural ingredients. Some benefits may be more difficult than others to provide through natural ingredients since they were designed into the synthetic molecules in a structure-function approach.
Shampoos: Shampoos, for all their ancillary benefits, are primarily meant to cleanse the hair. While the actual amount and type of surfactant necessary to promote the roll-up mechanism of soil and oil removal from fibers is quite minimal, the current consumer is looking for copious foam; in fact, it has been observed that many Asian consumers seek products whose foam density gives a “white glove” appearance on the hands during use. Therefore, the industry is compelled to come up with natural dense and high foamers. One type of natural surfactant found in a few plant varieties is the saponins, steroidal glycosides that readily generate foam in water. They work well for beverages where they are generally recognized as safe (GRAS) and impart copious foam to frothy drinks. However, in personal care, the do not impart a lather as rich as consumers expect from their shampoos at conventional use levels of less than 1%.
Of course, formulators could hark back to the old fashioned technology of liquid soaps by using unsaturated vegetable oil fatty acids, as some pioneers in natural products still do. Soaps made with oils from unsaturated fatty acids, such as olive, the traditional castile soap in Renaissaince Spain, or hemp oil, can remain clear in a concentrated solution. Mixed with coconut to enhance the lather, these liquid soaps do cleanse well but they experience solubility problems in hard water. One suggestion would be to add natural chelating agents such as phytate salts or inositol hexaphosphate to chelate with the divalent calcium and magnesium ions. However, pH effects may limit the usefulness of such techniques. Some such commercial agricultural sources include rice and soy.
If natural certification by bodies such as Ecocert is the standard followed, the surfactant choice becomes much wider, encompassing anionics such as acyl glutamates, acyl hydrolyzed protein salts and even alkyl sulfates and sulfosuccinates; amphoterics like the cocoamphoacetates; and nonionics in the alkyl glucoside family. Ranges of mild, high-foaming products can be formulated but the biggest concern is how to thicken these shampoos effectively and cheaply.
Formulators cannot get away with the conventional salt-thickening method used in many mass market, dollar-a-bottle shampoo variants but there are some natural polymers, such as xanthan gum, that can successfully be used. Work has also been done using magnesium sulfate (Epsom salts) in combination with fatty amphiphiles such as glyceryl laurate to thicken glutamate cleansers by building surfactant association structures akin to those using the cheaper monovalent salts.