Botox costs less in Korea for two plain reasons, and neither involves cutting corners. First, Korea makes its own botulinum toxin. Domestic brands like Nabota, Botulax, and Meditoxin are produced locally, so clinics skip the import markup that pushes up prices abroad. Second, the competition is fierce. Gangnam and Myeongdong alone pack hundreds of dermatology and plastic surgery clinics within a few blocks of each other, which keeps menu prices low and out in the open.
A single area in Korea often costs less than just the consultation fee at a Western clinic. For comparison, one unit of Botox runs roughly 10 to 25 USD in the US and 10 to 15 GBP in the UK. In Korea the same unit is frequently in the 2 to 5 USD range for a Korean brand. This is a steady gap, not a flash promotion.