Generally, CBD oil is made by combining an extract with a carrier fluid or oil. This question is best answered by looking at how the CBD oil was extracted. CBD oil can be extracted using CO2 systems or by using chemical solvents. Both methods produce a CBD oil byproduct that is then combined with a fluid like MCT oil, coconut oil, or olive oil so that it can be delivered to the body. Always check to make sure you know the CBD content of the products you purchase.