Want to make your emulsion thicker, more creamy and stable? Just add 1-2% of either:
cetyl alcohol (cetanol (1-hexadecanol C16));
stearyl alcohol (1-octadecanol C18); or
cetostearyl alcohol (blend of C16 and C18).
I’m a huge fan of these common higher alcohols. I use them in many product types including emulsions, hair conditioners, anhydrous balms/sticks. They are inexpensive, widely available, “natural” and provide emolliency, viscosity build and stability.
Let’s dig a little deeper….
Cetyl alcohol melts at 49.3°C and stearyl alcohol at 58°C. Many formulators like to use a combination of both. Making the alkyl distribution wider, by mixing the different chain lengths (C16 and C18) results in a more robust formulation, ability to cope with a wider range of temperatures, improved stability and a better lamellar gel network. You can buy a combination of C18 and C16 in a pre-made blend called, cetostearyl alcohol (commonly known as cetearyl alcohol) in ratios of: 30:70, 70:30 or 50:50. I like Croda’s Crodacol CS50 which is a 50:50 blend, has low odor and is purported to be less grainy than standard cetearyl alcohol blends.
Some notable differences:
Stearyl alcohol produces a whiter and more opaque product due to it’s longer carbon chain length. Cetyl alcohol breaks more easily when applied so gives a quicker spread and can hold onto more water than stearyl alcohol as it is more hydrophilic. This results in a higher gel phase which means a higher viscosity. However stearyl alcohol has a different crystalline structure and is less polar resulting in a a more stable viscosity, unlike cetyl alcohol whose viscosity can increase over time.
Do you use fatty alcohols in your formulas? What is your experience of them?