The human body has an endocannabinoid system — a natural system that maintains homeostasis or balance, in the body. The endocannabinoid system has CB1 and CB2 receptors. These are found throughout the body. CB1 receptors are generally located in the central and peripheral nervous system and CB2 receptors are generally found in the brain, immune system, and gastrointestinal system. CBD binds to these receptors creating changes and effects in the body
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.