Full-spectrum CBD is more than just CBD. A lot more. It’s the entire roster of cannabinoids and terpenes present in a given hemp strain that work together synergistically to amplify the effects of the CBD. Full-spectrum CBD does contain a trace amount of THC (less than 0.3%), which won’t get you high, but it’s something to avoid if there’s a chance you’ll be drug tested.
Broad-spectrum CBD is essentially full-spectrum CBD, further processed to remove all traces of THC. This allows those who need to avoid THC to still enjoy the beneficial effects of the other cannabinoids and terpenes.
Isolates are pure CBD, no THC whatsoever, but none of the other phytochemicals, either. So it doesn’t have the same level of efficacy as full- or broad-spectrum CBD, but it’s a safe choice for those who can’t have even trace amounts of THC. It also tends to be the least expensive of all the options, offering a lower barrier to entry for those just discovering CBD.