Base oils used to be just that - base oils - used mostly as a base for the more active essential oils and as a basic moisturiser.
Now though, there are myriad base oils and we are far more knowledgeable about what they are capable of. Base oils come in many different weights - some are thick and viscous, some are light and some are medium weight. Some are more easily absorbed by the skin than others. They can be antioxidant, antiviral, help to smooth fine lines or even help to regulate oil secretion. Their possibilities are endless.