humectants are a girl's best friend. They draw water from the atmosphere to our hair or skin to moisturize them. We use them pretty much every product we make - if possible - but some people are wary about using humectants in hair care products.
Humectants can be amazing inclusions in hair care products to help moisturize our hair without the use of oils. If you have dry hair, you know the value of more moisture. If you have oily hair, you know the value of moisturizing without oils. But if you're a frizzy haired girl, you probably avoid humectants at all costs because our hair doesn't absorb water uniformly, leading to the poofy poodle look!
Everyone can use humectants in their products - it's all about the dosage. Panthenol is a great ingredient for everyone's hair, and using it at 2% will offer you so many amazing benefits without tons of poofiness. Low molecular proteins like silk will penetrate your hair shaft to offer moisturizing from within and can behave as humectants (more about this in this next few days, or click on the link). Aloe vera can offer film forming and hygroscopic properties, but the frizzy girls might want to use it at 5% or less.
If you're buying hair care products, the amount of aloe vera you'll find is very small, probably not enough to actually do anything for your hair. You need at least 10% to make any difference to the moisturization of your hair and scalp. I know a lot of people avoid aloe vera in hair care products - in commercial products, it's probably a lot of work to avoid it for what probably isn't a big difference in your hair.
I've seen people avoiding glycerin in shampoo because of the belief that at certain humidities, the glycerin will suck the water out of your hair. There's not enough water in your hair - it'll go for the environmental water as it's simply easier to get that than to go to all the trouble of working on the moisture in your hair! We find glycerin in shampoo as both a humectant and a bubble enhancer, and the amount found is fairly low - probably less than 3% - and there'll be less than that left after you rinse. You may find glycerin in your rinse off or leave-in conditioners, where it will act as a humectant to offer extra moisturization without oils.
If you can find some information on humectants drawing water out of your skin instead of drawing water to it, please provide me with links or citations. I have found tables of water binding ability of various humectants showing that glycerin increases in its water binding abilities as humidity increases and decreases, but I've not been able to find that glycerin will draw water from your skin or hair. As my charts only go to 31% humidity, there may be more information out there and I'd love to see where this idea originates.
Sodium lactate and sodium PCA are awesome humectants, but they will wash off when you rinse your hair. When you see sodium lactate in shampoo or conditioner bars, they are there as bar hardeners.
If you're a dry haired girl, feel free to add 3% glycerin to any of the rinse off conditioner recipes you see on this blog in place of 3% water. I think everyone should add 2% panthenol to the cool down phase of their conditioner recipes - if I haven't included it, feel free to add it and remove 2% water in the water phase. And adding 10% aloe instead of water can help with moisturization as well!
Have fun formulating!