Saturday, October 26, 2013

Deciphering Glycerin

Now that winter is basically here, I was trying to decide whether I want to try using my glycerin based products in the winter time. Based on my research, I don't. Glycerin (also called glycerol or glycerine) has two common uses in hair care -- as a lubricant and as a humectant. For hair purposes, that means it can improve the smoothness of the hair strand; and it can draw moisture to it and slow down the rate at which water is evaporated from it. Glycerin is water soluble, which means that it mixes well with water.

There are two reasons to be careful when using glycerin. First, like any humectant, pure glycerin can be drying because it may pull water from the lower layers of skin onto the surface where the water can easily be evaporated into the air or rubbed off (i.e., with a hat or scarf). It can also be sticky if you use too much. Thus, it is important to always dilute it. When making my own water spritz, I usually mix about 2 tablespoons of glycerin to 4 oz. of water.

Second, the effects of glycerin can vary by the humidity in the air. This is a sister point to the first one. Because glycerin likes to draw water to it, in humid weather, this means that it is pulling water from the air. This can be beneficial because it helps to moisturize your hair. However, if you find that your hair is getting frizzy in humid weather, you may need to cut back on glycerin. In dry / arid weather, glycerin may pull water from your hair and skin because it cannot pull it from the air. Thus, if you are going to use glycerin in a dry climate, make sure that the glycerin-containing product also contains water. If it does not, you could do the baggy method or take a steamy shower to infuse water into the glycerin before it hits the dry air. You could also try using a sealant, like an oil, to keep the water from leaving your hair when it is pulled to the surface.

To determine the humidity in the air, it is best to look at the dew point, rather than the humidity. When the weather channel mentions humidity, however, they are usually talking about “relative humidity”, which is the amount of water vapor in the air compared to what could be in the air at the current temperature. The dew point is a specific measurement of the amount of water vapor in the air. A dew point above 60^o F is usually considered humid, and a dew point below 40^o F is usually considered dry.

As a disclaimer, I don’t plan to check the weather channel every morning before doing my hair. I just go based on feel. Optimally, I would use glycerin mixed with water and styling products with glycerin high on the list in medium dew point temperatures (40o-60o). However, because my hair is low porosity, my hair does not frizz easily in high humidity, so I’m less concerned than others might be in the summer, but I still don’t want to overdo it. Thus, I will probably use glycerin more freely in the spring, summer and early fall; and I would avoid using glycerin-based stylers and moisturizers in late fall and all of winter, though it is still okay to use glycerin-based conditioners. Of course, where glycerin is low on the product ingredient list, then these rules of thumb are less important.