These are laws regarding what can go into a supplement.
Wouldn't caffeine fall under this umbrella?
In this sense it means the natural product rather than the synthetic product. i.e. caffeine from coffee beans falls under this definition but synthetic caffeine does not (even if the precursor is natural. Also natural menthol from Mentha piperita
fits the definition but synthetic menthol prepared from α-pinene.
In some cases it is necessary to obtain a certificate of analysis from the manufacturer / vendor unless you have the analytical capabilities for impurity profiling.