There are three main formulations for CBD extracts – full spectrum, broad spectrum and CBD isolate. In a word, full spectrum means what it sounds like – it contains the full spectrum of cannabinoids and compounds found in the natural plant, including CBD, CBG, CBN, terpenes, flavonoids, and yes – trace amounts of THC. Not to worry – to be sold legally, CBD products must contain less than 0.3% THC by volume. That’s low enough that the vast majority of users will never notice any psychoactive effect. 

Let’s take a look at the three main formulations of CBD extract:

Full Spectrum CBD 

Like the name implies, full spectrum CBD contains all of the compounds you’d find in a fresh, unprocessed hemp plant. This whole-plant formulation is considered by many to be the most effective, since it replicates the compounds and effects of natural hemp flower, producing what’s called the Entourage Effect (basically, these compounds work best when taken together). However, for those who are sensitive to THC, or who undergo drug testing, the presence of even trace amounts of THC can be undesirable.

Broad Spectrum CBD

Broad spectrum CBD is the exact same thing as full spectrum CBD, but with any trace amounts of THC removed. You’ll still get many of the beneficial effects associated with whole-plant extracts, but without any risk of testing positive for THC. This might also be a good option for pets, children, or anyone else who needs to avoid THC. 

CBD Isolate

This method isolates the CBD from the rest of the hemp’s natural compounds. It The result is a crystalized solid, or white powder, with no impurities – it is 99% pure CBD.     

Source: https://americanmarijuana.org/what-is-full-spectrum-cbd/