Different drug tests will set different limits on the amount of THC that you are permitted to have in the blood. Full-spectrum CBD products are generally made with a small level of THC, due to the small quantity that was initially in the hemp. This will, because of the law, always be less than 0.3%, and no psychoactive effect is possible in that amount.
So how does it work? Scientists are still working out the details of how CBD works to calm the mind, though it seems that its effects on serotonin and glutamate production are part of that equation. This comprehensive 2015 review of scientific literature on CBD as a potential treatment for anxiety concluded that CBD has considerable potential and strongly recommended further study. cbd oil