Update February 2021:
From what I understand, there is a big difference between the CBD that you get at the health food store vs. the CBD that comes from the Medical Marijuana Dispensary. If you combine the CBD with THC, first of all, it is much more medicinally potent. And according to the dispensary, their CBD-only products are derived from the "actual medical plant" wheras the CBD that comes elsewhere is from industrial hemp plants.
When I first heard about CBD oil, my initial assumption was that it would be "like" non-alcoholic beer. Taking the THC out of marijuana is like taking the alcohol out of beer, right? Wrong!
I learned first-hand that CBD oil does have relaxing, calming effects. It's also an anti-inflammatory, meaning it can help your body heal from virtually anything. It can be taken orally (using a dropper) or by vaping it. I've tried it both ways. Vaping is generally more 'cost effective' because the CBD goes directly into your lungs and blood stream, rather than absorbing slowly through your gut.
Doctors and medical professionals are more likely to 'prescribe' something that can be taken orally compared to smoking or vaping. When discussing disage amounts, the amount that you consume by swallowing it is easy to replicate. You measure out the chosen amount and all of it goes "down the hatch."
The downfall of vaping is that it's tough to measure: is the patient fully inhaling? How long are they holding it in? Since not all patients breathe and inhale the same way, it's tough for doctors to know how much CBD their bodies are absorbing.
How do I actually vape CBD oil?
The downfall of vaping CBD oil is it's less convenient. It comes in a bottle with a 'dropper' for oral consumption. So in order to vape it, you need to buy a refillable vape cartridge:
and an industrial syringe so that you don't make an enormous mess when trying to fill up the cartridge:
Important: Not all CBD oils are created the same! You want to look for pharmaceutical grade CBD oil.