Illegal attempts to import weight-loss drugs Wegovy and Mounjaro into South Korea surged more than threefold in the first half of this year, with 4,155 cases detected between January and June — far outpacing the 1,189 cases recorded across all of 2025, according to data released by the Korea Customs Service on Monday, 24 August. The sharp rise underscores a growing black-market appetite for GLP-1 receptor agonist medications, which have seen surging global demand.

Scale of Illegal Imports

The bulk of illicit shipments arrived through postal channels. The customs agency intercepted 3,489 illegal mail parcels containing Wegovy and Mounjaro in the first half of the year, more than triple the 1,046 mail cases logged in all of 2025. Separately, 656 cases involved travellers carrying the medications in personal luggage — up sharply from 134 such cases last year. Both Wegovy and Mounjaro are banned from being brought into South Korea in hand luggage.

Legal Clearances Also Rising, But Dwarfed by Violations

Legal customs clearances for the two drugs also increased, with 391 cases cleared in the first six months of this year compared with 191 cases in all of 2025. However, legal imports remain a fraction of detected illegal attempts, pointing to a significant supply-demand mismatch within South Korea's regulated pharmaceutical market. Most illegal purchases are reportedly being made through overseas online marketplaces, with buyers using international shipping services to receive the drugs.

Customs Authority Issues Warning

A senior official from the Korea Customs Service issued a direct warning to prospective buyers. 'Unauthorised imports of Wegovy and Mounjaro are a serious violation of the Customs Act and are subject to punishment,' the official said. 'We will thoroughly block the illegal inflow of harmful pharmaceuticals at the border.' The agency has indicated it will intensify border surveillance targeting pharmaceutical shipments.

South Korean Pharma Companies Ramp Up R&D

This comes amid a broader push by South Korea's domestic pharmaceutical sector to develop homegrown alternatives. Major companies each spent approximately 100 billion won on research and development in the first half of the year. Yuhan Corp., known for its anti-inflammatory product Antiphlamine, invested 122.2 billion won in R&D during the January–June period — a 13.8% rise year-on-year, representing 10.5% of its first-half sales, according to its regulatory filing. Chong Kun Dang Pharmaceutical Corp., maker of the household pain reliever Penzal, channelled 113.5 billion won — or 12.3% of first-half sales — into new drug development, a 36.6% jump compared to the same period in 2025. The R&D surge signals that domestic players are racing to secure a foothold in the obesity and metabolic drug market before international brands fully consolidate their lead.