Japanese medical experts have warned of side-effect risks as more people turn to obesity and diabetes drugs such as Mounjaro and Wegovy for cosmetic purposes or weight loss.
The Japan Society for the Study of Obesity said in a recent statement that people using GLP-1 drugs such as Mounjaro to lose weight should choose safe methods, according to Japan's NHK and Kyodo News on the 4th.
Rapid Weight Loss Can Build Up Ketones, Causing Vomiting and Abdominal Pain
The society said that cutting food intake excessively while taking the drugs, leading to sharp weight loss over a short period, can cause ketones produced during fat breakdown to accumulate in the body at excessive levels.
That can bring on vomiting, abdominal pain and severe fatigue, and the condition may progress to ketoacidosis if it worsens.
Ketoacidosis is a state in which blood becomes acidic as ketone levels rise excessively. In severe cases it can cause dehydration and reduced consciousness, requiring emergency treatment.
The society noted that people without obesity or diabetes who use the drugs for cosmetic reasons or simple weight loss may experience side effects that have not been sufficiently verified in existing clinical trials.
The society urged caution, saying that using these drugs while severely restricting food intake "must absolutely be avoided," according to Kyodo News. GLP-1 drugs are also known to carry risks of pancreatitis and intestinal obstruction in addition to vomiting.
About 950 Mounjaro Side-Effect Reports, Including 35 Tied to Dieting or Cosmetic Use
Japan has seen a stream of reports from people who experienced adverse reactions after using Mounjaro for cosmetic or weight-loss purposes outside its approved use.
About 950 cases of Mounjaro-related side effects were filed with Japan's Pharmaceuticals and Medical Devices Agency (PMDA) between 2023 and the 22nd of last month. Of those, 35 involved adverse reactions reported after the drug was used for purposes other than intended, such as dieting or cosmetic treatment.
Mounjaro is an injection containing tirzepatide and is approved in Japan as a treatment for type 2 diabetes. An obesity treatment with the same active ingredient is licensed under the name Zepbound. Japanese authorities also set dosing criteria for obesity treatments, including a certain level of obesity and the presence of health problems.
In Japan, some medical institutions prescribe prescription-only drugs for cosmetic or weight-loss purposes through "free treatment," a form of care not covered by health insurance.
The Health, Labor and Welfare Ministry has separately warned that GLP-1 drugs such as Mounjaro should not be used casually as if they were simply weight-loss pills.
The ministry said the safety and effectiveness of using the drugs for cosmetic or dieting purposes has not been established in some cases, and that unexpected health damage can occur.
Buying Drugs on Social Media Carries Greater Risk, With No Compensation for Side Effects
Obtaining the drugs outside licensed medical institutions has also been flagged as a problem.
The ministry warned that person-to-person trade of pharmaceuticals through social media or online secondhand marketplaces is illegal, and that products circulating this way may include counterfeit drugs, products of degraded quality, and items whose ingredients and content levels are difficult to verify.
It also stressed that people who develop serious side effects while using the drugs for unapproved purposes such as cosmetic treatment or dieting are unlikely to receive compensation under Japan's relief system for drug side-effect damage. The system in principle covers cases in which serious health damage occurs even though a drug was used in line with its approved purpose and dosage.
Demand for obtaining the drug from Japan has also emerged abroad, as a perception spread that Mounjaro is priced relatively low in Japan compared with some other countries.
In South Korea, the practice of getting Mounjaro prescriptions or purchases in Japan has even produced a new coinage, "sushi-zaro," combining sushi with Mounjaro.
Experts stress, however, that using the drugs indiscriminately based only on price or weight-loss effects is dangerous, and that obesity treatments must be used under the diagnosis and supervision of medical professionals.
