Cannabigerol (CBG) is a cannabinoid that seems to operate as a precursor to other cannabinoids. The acidic form of CBG (CBGa) is abundant in young cannabis plants. Over time, it breaks down into CBD and THC. This has led many to call CBG the “mother of all cannabinoids.” While CBG breaks down into other cannabinoids you may already know and love, it’s unique and has its own effects.