Advice on importing vitamin supplement from USA for private use

Hi everyone. Just a quick question about importing supplements into Thailand. The import duty and various fees payable to the custom excise on vitamin supplement imported from USA seem to be getting out of proportion. For the last shipment I had to pay around 50% of the value of the goods in fees and duty! Any advice on how to get around these hefty import duties? I’ve read somewhere that the FDA license can take ages to be granted and maybe very costly, so perhaps using a third party company that have the FDA license already it would be an alternative way to go. Anyone knows a reputable import/export company that doesn’t charge an arm and a leg and deals with small volume packages? Otherwise has anyone any advice on other possible methods?

Thanks a lot in advance.