THC-O products are in a particularly precarious legal situation. Last week, the DEA stated that THC-O products are federally illegal because the compound is not found naturally in hemp. The agency was not asked to evaluate the legality of HHC, but whether or not those products will eventually be considered illegal will depend on whether regulators believe that it can be found naturally in the cannabis plant. Under federal law, the possession and consumption of cannabis in all its forms remains illegal.
There are some prescription drugs approved by the FDA that contain products derived from cannabis, such as CBD, or are made with synthetic products related to cannabis. The FDA has not approved the cannabis plant for any medical use. However, the FDA has approved several drugs that contain individual cannabinoids.