Some friends claim that it helps, some say it's a total waste of money and a Ponzi scheme of sorts.
Two somewhat impartial studies:
https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326553/
Bottom line is more controlled clinical studies are needed. Also, CBD is interpreted by the Drug Enforcement Administration, Food and Drug Administration, and Congress to be a Schedule I substance and therefore it is illegal in all 50 states under Federal law.
UPDATE: (2018 change)
The U.S. Drug Enforcement Administration has taken some cannabidiol out of the most restrictive class of controlled substances, a move that allows the sale of the first nonsynthetic, cannabis-derived medicine to win federal approval. It’s a decision that immediately affects CBD producers but also signals the agency’s first admission that the plant has medical value.
The DEA announced Thursday that drugs including CBD with THC content below 0.1% are now considered Schedule 5 drugs, as long as they have been approved by the U.S. Food and Drug Administration. It is the first time the agency has lowered any type of cannabis from Schedule 1.
Travel with it at your own risk as far as TSA goes (they can't test for 10th of a percent on site):
Marijuana and certain cannabis infused products, including some Cannabidiol (CBD) oil, remain illegal under federal law except for products that contain no more than 0.3 percent THC on a dry weight basis or that are approved by FDA. (See the Agriculture Improvement Act of 2018, Pub. L. 115-334.) TSA officers are required to report any suspected violations of law to local, state or federal authorities. TSA’s screening procedures are focused on security and are designed to detect potential threats to aviation and passengers. Accordingly, TSA security officers do not search for marijuana or other illegal drugs, but if any illegal substance is discovered during security screening, TSA will refer the matter to a law enforcement officer.