Korea vs USA supplements — regulation, seals, labeling

The same supplement is regulated, certified, and labeled differently in Korea and the US. As cross-border shopping grows, understanding these differences helps you choose wisely.

Regulation

Korea's MFDS pre-approves functional ingredients under a "health functional food" system, shown by a mark and approved-claim text. The US has no pre-market approval (DSHEA); the FDA does not review products before sale. Instead, consumers look to third-party seals like USP and NSF.

Units

Korea mostly uses IU; the US often shows both IU and mcg. For vitamin D, 1000 IU = 25 mcg. Watch the units when buying imported products.

Case study: melatonin

The starkest difference. In Korea, melatonin is a prescription drug. In the US, it is an OTC supplement you can buy at a store. The same molecule holds a completely different status in each country.

Brands and channels

Popular brands and stores differ too — pharmacies/Olive Young/online in Korea, Amazon/iHerb/Costco in the US. Every ingredient page here includes a "Korea vs USA" comparison so you can see both markets together.