Elzbieta Kasprzyk, TRI-K Industries Inc. and Lori Siegler, Larex Inc.

Key words: galactoarabinan (GA), emulsion, particle dispersion, film-forming, SPF

Abstract: Studies presented here show that GA reduces emulsion particle size and facilitates the aqueous dispersion of particulate materials, thus demonstrating how it improves the SPF of organic, inorganic and mixed sunscreen preparations.

Formulators continue to search for ways to improve SPF without increasing the level of approved sunscreen actives in formulations. SPF-boosting ingredients such as botanicals with UV-absorbing properties, film-formers and dispersing aids often are investigated, in addition to new technologies and formulation techniques.

Larch extract, galactoarabinan (GA), is a naturally occurring polysaccharide extracted from the Western larch tree and tamarack tree of the genus Larix. It has been used as a dietary supplement to support healthy immune system function.1,2 Larch GA also is an excellent source of dietary fiber and has been approved by the U.S. Food and Drug Administration (FDA) for this purpose.

Recently, this natural ingredient has found its way into personal care. Studies have demonstrated its ability to minimize the appearance of fine lines and wrinkles, reduce transepidermal water loss (TEWL) and enhance alpha hydroxy acid (AHA) skin exfoliation without irritation. In addition, GA decreases emulsion particle size and facilitates the aqueous dispersion of particulate materials such as micronized titanium dioxide. The combination of these properties makes larch extract an interesting sun care ingredient. The present article briefly reviews the properties of this ingredient. By examining in vitro data, the authors also demonstrate how GA improves the SPF of organic, inorganic and mixed sunscreen preparations

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