Pharmacology published a study in 2016 looking at medical marijuana for migraines, specifically in relation to its effects on serotonin, with very positive results. You’ll notice that neither study looked at CBD in isolation from other cannabinoids (which is an issue with a lot of research on CBD and pain). Truthfully, the research on CBD alone just isn’t sufficient to make any pronouncements about its effects on headache pain.
Dry Mouth: As is the case with many other hemp- and marijuana-based products, CBD oil often leads to a condition known as dry mouth (or cottonmouth). This is likely due to cannabinoids altering receptors in the lower jaw that trigger salivation. In most cases, mild discomfort and stronger-than-average thirst are the only issues associated with dry mouth.