Besides possible import taxes, the second big thing that should be taken into account when ordering internationally is that importing certain supplements is prohibited by law in some countries.
This may be because the supplement in question is considered a pharmacy grade medicine or that the product may contain ingredients that are deemed illegal for other reasons.
For example, the importing of Adrenal extracts, GABA, DHEA, Lithium, Melatonin, Progesterone, and Yohimbine is prohibited in some countries.