Quality is a particular concern, because cannabis plants easily soak up heavy metals from pesticides and other contaminants, Marcu says. If you are buying online, look for a company that documents how it tests its products. (If the website doesn’t indicate this, call and ask.) “Buying from a reputable manufacturer is crucial, because it matters how the plant is cultivated and processed,” Dr. Maroon says. One clue that a company is cutting corners: too low a cost. Good CBD is pricey—a bottle of high-quality capsules is sold in Cohen’s office for $140. But for many, it’s worth the money. Roth spent $60 on her tiny bottle. But when her energy returned the day she started taking CBD, she decided that was a small price to pay.
Only high grade CBD oil is used for manufacture of e-liquid or vaping oil that is used in electronic cigarettes.  The vaping liquids used in both disposable and non disposable electronic cigarettes are made as compounds with CBD oil, alkaline e-liquids, vegetable glycerin, flavors and also nicotine to give smokers the feeling of a real cigarette. But buyers of e-liquid refills should read the details of ingredients on the bottle of e-liquid to ensure that they are not using synthetic ingredients like propylene glycol or formaldehyde.
So which is better? Hemp derived CBD or Medical marijuana derived CBD?  I believe, given the information I have found, that the reasonable and definitive question we should ask is: What are the pros and cons of both options and, most of all, what will be best for me and fit my lifestyle. In addition, legality within the state and country you live must be taken into consideration. 

Blood pressure. Scientists say that CBD can also aid the lowering of blood pressure in humans, mainly by reducing the body's systolic pressure in the arteries as the human heart pumps blood. By taking a moderate dosage of CBD oil, some health experts say, an individual can improve blood flow, lower the heart rate and reduce the anxiety the stress often found in patients with high blood pressure.
Zuardi, A. W., Crippa, J. A., Hallak, J. E., Bhattacharyya, S., Atakan, Z., Martin-Santos, R., … & Guimarães, F. S. (2012). A critical review of the antipsychotic effects of cannabidiol: 30 years of a translational investigation [Abstract]. Current Pharmaceutical Design, 18(32), 5,131–5,140. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22716160
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