Prescriptions for GLP-1 obesity drugs in South Korea are rising so fast that combined prescriptions for Wegovy and Mounjaro surpassed last year's full-year total in just five months. Driving the increase is the spread of so-called "drug shopping," in which patients first choose the drug and dose they want on telemedicine platforms and then look for a clinic willing to prescribe it, along with growing demand for "sushi-zaro" — buying the medication in Japan, where prices are lower.
Wegovy and Mounjaro prescriptions totaled 1,457,639 in the first five months of this year, according to data on obesity drug prescriptions cleared through the Drug Utilization Review (DUR) system, submitted by the Health Insurance Review and Assessment Service to the office of Rep. Kim Yoon of the Democratic Party of Korea on the 11th. That exceeded the 1,222,574 prescriptions recorded for all of last year. Through August, the cumulative total reached 2,789,992, roughly 2.3 times last year's annual figure.
Monthly volumes have also climbed quickly. Combined Wegovy and Mounjaro prescriptions rose from 250,121 in January to 466,272 in July, an increase of more than 86% in six months.
Mounjaro led the growth. Its share of combined Wegovy and Mounjaro prescriptions rose to 86.9% in August from 70.2% in January. Over the same period, Wegovy prescriptions fell 18.5% to 60,763 from 74,517, while Mounjaro prescriptions rose 2.3 times to 404,602 from 175,604.
Prescriptions dropped off sharply at higher doses, however. In August, there were 173,340 prescriptions for the 5 mg dose of Mounjaro, compared with 38,242 for the 7.5 mg dose, 77.9% fewer. The ex-factory price jumps to 521,377 won for 7.5 mg from 369,307 won for 5 mg, suggesting cost is weighing on patients' decisions to step up their dose.
Prescriptions for the highest doses, by contrast, have grown rapidly since their launch. In June, there were only 224 prescriptions for the 12.5 mg dose and 93 for the 15 mg dose. By August, those numbers had risen to 2,837 and 1,909 — increases of 12.7 times and 20.5 times in two months.
Easier access through telemedicine platforms is cited as another factor behind the rise in GLP-1 obesity drug prescriptions. On some platforms, patients can select the drug and dose they want — Wegovy or Mounjaro, for example — and then book an in-person appointment at a clinic that can prescribe it. As that sequence spreads, obesity drugs are increasingly being compared and chosen like ordinary consumer goods.
With prescriptions easier to obtain, the search for lower costs is also moving overseas. In particular, a practice known as "sushi-zaro" is spreading, in which patients obtain prescriptions in Japan, where Mounjaro is cheaper than in Korea, and bring the drug home. A one-month supply of the lowest 2.5 mg dose can be prescribed in Japan for about 10,000 yen (roughly 85,000 won), compared with 280,000 to 350,000 won in Korea. The gap widened further after Japan's Ministry of Health, Labor and Welfare cut Mounjaro's price by 25% in August.
Customs holds on such imports have surged as well. The Korea Customs Service detected just four cases of illegal imports of obesity drugs including Mounjaro and Wegovy last year, but 5,030 cases in the first eight months of this year. Of the items held at customs this year, 63.3% arrived from Japan and 21.8% from China.
A medical industry official said wider access to obesity drugs is a positive development but that the spread of patients choosing a specific drug and dose before finding a prescriber warrants caution. "GLP-1 obesity drugs are not simple diet aids but prescription medicines that require a doctor's order," the official said. "The appropriate dose must be selected and adjusted under medical supervision, taking into account each patient's health condition and the risk of side effects."