In 1992, American and Israeli researchers discovered new brain receptors that showed interesting properties. These new receptors were called endocannabinoid receptors and brain chemicals that react with these receptors are called endocannabinoids. The first one isolated was called anandamide, followed by several others. These newly discovered brain neurotransmitters affected several mechanisms in the body. But the most interesting finding was that the active ingredients in marijuana, such as THC, which causes the familiar high feeling associated with marijuana, work by interacting with these endocannabinoid brain receptors. As such, the body produces compounds that are similar to THC. Research initially suggested endocannabinoid receptors were only present in the brain and nerves, but scientists later found that the receptors are present throughout the body, including our skin, immune cells, bone, fat tissue, liver, pancreas, skeletal muscle, heart, blood vessels, kidney, and gastrointestinal tract. We now know the endocannabinoid system is involved in a wide variety of processes, including pain, memory, mood, appetite, stress, sleep, metabolism, immune function, and reproductive function. Endocannabinoids are arguably one of the most widespread and versatile signaling molecules known to man. You can read more about how the endocannabinoid system works here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3997295/
As noted, THC, the most active component of marijuana interacts with the brain cannabinoid receptors (there are two, CB1 and CB2) but another substance also derived from the same cannabis plant as marijuana doesn't produce the mental effects as does THC, but provides a number of other benefits that have made it the most popular herbal supplement sold today. That substance is cannabidiol (CBD), and its use is mired in controversy because its popularity is far in excess of any research that proves its many purported benefits. The cannabidiol market has skyrocketed in recent years, with it being available in many forms, such as CBD oil, coffees that contain it, even maple bacon-flavored dog biscuits.
The most popular use of CBD is to treat pain and inflammation. Some users of CBD claim that it reduces pain better than drugs such as non-steroidal anti-inflammatory drugs used for the same purpose. But the users of CBD prefer it to the drugs because they consider it more natural and less likely to cause side effects, both of which are true. Whether it actually reduces pain better than drugs has not yet been proved in scientific studies. In fact, CBD produces most of the benefits of marijuana but because it doesn't contain THC, you can't get high on it. One 2004 study that involved lab . . .