Unlike CBD, CBG has not been approved as a drug, and FDA itself has acknowledged that “parts of the cannabis plant that do not contain THC or CBD might fall outside the scope of the [drug exclusion rule].” If CBG is approved as a drug at some point down the line, it also seems likely that the drug exclusion rule would not apply: this is because the rule contains an exception for substances marketed as foods or dietary supplements prior to any FDA clinical investigation. People are already marketing CBG products as foods and dietary supplements.
This domestic legal framework, alongside the fact that CBG can be lawfully produced and extracted from hemp under the 2018 Farm Bill, seemingly gives CBG a viable legal runway. Of course, everything here is conditioned on manufacturers and sellers steering clear of unapproved health claims.