SCIENCE FRIDAY: Making a (Daily) Lotion
I am obsessed with making things. This past year for Christmas, James and I decided to make lotion to give to our friends and family. Initially, we had plans to make several scents with essential oils and give everyone a sample 4 pack of our favorite scents. This proved to be a rather difficult endeavor in practice in our small galley kitchen.... on Christmas morning because I had been working too much the past few weeks and had not had time previously to make it. Either way, it was an incredibly rewarding and valuable experience and given that we are making more lotion now, I figured it was an appropriate science Friday post.
There are multiple uses of lotions both medicinal and cosmetic. Lotions may be prescribed for various skin conditions by a dermatologist, be used for their anti aging or wrinkle correction effects, or simply to moisturize. The lotion we are focusing on today is for regular daily moisturizing.
In order to make a basic every day lotion, there are a few required components. Compared to creams and gels, lotions need to have lower viscosity. The majority of lotions are oil in water emulsions with a fatty acid alcohol (usually a cetostearyl alcohol) used to keep it together. By definition, an emulsion is composed of two compounds that do not normally mix, therefore, the fatty acid alcohol can bind in together and keep the lotion mixed.
The process of making a lotion must be tightly controlled to avoid forming long agglomerates or other side products. For example, the process of making a lotion usually involves creating an oil phase, separately creating the water phase with the emollients, and then mixing the two usually with heat and controlling the viscosity. If it is too viscous, it is a cream. This is usually accomplished in a commercial grade mixer (at our house, just a regular Kitchenaid mixer) but there is increased popularity of a technique called sonolation. This uses a high powered homogenizer that accelerates the material at 300 ft / second with a pressure of 5000 PSI. We use these in research to process tissue... that is how powerful they are.
After the solution is completely mixed, you can add aromatic oils to scent the lotion as desired. When we made lotion, we made an unscented version, a eucalyptus, a citrus, and a lavender scent. The oils can also be added to the water phase before you mix the lotion together. However, we usually wait until after it is mixed so that it does not break down in the process.
When we were making lotion during the winter, we also added coconut oil to our mix as well as shea butter to make it more hydrating. The side effect of these is that it make the lotion oily. It was incredibly hydrating and I still use it when my skin is dry, but it also took a long time to dry once it was applied.
Being that I work in the sciences, we also tried multiple different oil based compounds as well as emollients but found that the simplest way to make a hydrating lotion at home is the same way it has been done forever: Velvachol, Glycerin, and water. Once it is mixed, you can add scents as desired. Everything is available on Amazon so it is easy to make. Just package in small jars and it is ready to go!