Illegal imports of obesity drugs surge 3.5-fold in Korea

The number of illegally imported obesity treatment drugs detected surged in the first half of this year, driven largely by drugs ordered from foreign websites and shipped through international mail.

According to the Korea Customs Service (KCS) Monday, authorities detected 4,155 instances of illegal imports of Mounjaro, Wegovy and other obesity drugs between January and June, nearly 3.5 times the 1,189 cases for all of last year.

Novo Nordisk's Wegovy and Eli Lilly's Mounjaro are both once-weekly injectable obesity treatments that suppress appetite. Wegovy launched in Korea in 2024, while Mounjaro followed in 2025. Illegal import cases have risen quickly since the two drugs' domestic debuts, from four cases in 2024 to 1,189 last year and more than 4,000 in the first half of this year.

By comparison, only 596 cases were formally cleared through customs via import companies over the same period, rising from 14 in 2024 to 191 in 2025 and 391 in the first half of this year.

International mail was the most common route, accounting for 84.8 percent of cases, as more people ordered the drugs from overseas sites and had them shipped by mail. Mail cases rose from two in 2024 to 1,046 last year and 3,489 in the first half of this year.

Imports through travelers' personal belongings also rose, from one case in 2024 to 134 in 2025 and 656 in the first half of this year.

The biggest driver behind the surge in overseas purchases of Wegovy and Mounjaro is their lower price. A one-month supply can be bought through overseas websites for about 150,000 won ($109), less than half the cost of the same supply obtained through a prescription at a domestic clinic.

Under KCS notices, general medications can be brought into the country for personal use in limited quantities, up to six bottles or a three-month supply. But Mounjaro and Wegovy are designated as “harmful drugs” by the Ministry of Food and Drug Safety and cannot be brought in without a letter certifying an exemption from import requirements.

The rise in illegal imports comes as demand for the drugs has surged among younger Koreans. According to drug utilization review data submitted by the Health Insurance Review and Assessment Service to Rep. Han Zee-a of the People Power Party last month, Mounjaro was prescribed more than 1.5 million times between its domestic launch last August through May this year.

By age group, people in their 30s accounted for the largest share at 36 percent, followed by those in their 40s at 27.1 percent, those in their 20s at 16.9 percent and those in their 50s at 14.6 percent.

Prescriptions for teenagers have continued to rise. Monthly prescriptions for the age group stood at 82 at launch and surpassed 1,000 in December last year. The trend has continued this year, with monthly prescriptions rising 1.5-fold from 1,739 in January to 2,594 in May.