Japan obesity society warns against weight-loss use of diabetes drug Mangiaro

In short

The Japan Society for the Study of Obesity said on Oct 3 that using diabetes drugs such as Mangiaro (tirzepatide) for weight loss while sharply restricting food or carbohydrates has been linked to ketosis and ketoacidosis, which can be life-threatening, and called for the combination to be avoided. The society, which released the statement at a meeting in Utsunomiya, listed warning signs including nausea, vomiting, abdominal pain, severe fatigue and confusion, and said users should stop the drug and seek medical care. Asahi reported that a woman in her 20s with a BMI in the normal range was hospitalised after using such drugs obtained through a self-funded online clinic.

Why it matters

The warning concerns drugs increasingly used for cosmetic weight loss, which the society says it does not recommend off-label; for users of such drugs, the practical consequence is to watch for the listed symptoms and seek care quickly. The society also said weight loss itself should be judged for safety, citing risks such as reduced bone mass and menstrual irregularities. The documents give no figures on how many cases have been reported, so the scale of the problem is not established.

Key facts

• The Japan Society for the Study of Obesity released a statement on Oct 3 warning against using diabetes drugs such as Mangiaro (generic name tirzepatide) for weight loss together with excessive food or carbohydrate restriction. [ 1 , 2 , 3 ]
• The society said reports are increasing of ketosis and of ketoacidosis, a condition in which the blood becomes acidic and which can be life-threatening, among people using the drugs for weight loss rather than for medical treatment. [ 1 , 2 , 3 ]
• Warning signs listed by the society include unusual sweet-acrid breath, nausea, vomiting, abdominal pain, inability to eat or drink, severe general fatigue, drowsiness, difficulty breathing and confusion. [ 2 , 3 ]
• GLP-1 receptor agonists such as Mangiaro carry concerns about side effects including vomiting, pancreatitis and ileus, and the society said the type, frequency and severity of side effects may differ for people who are not obese or diabetic. [ 2 ]
• Asahi reported a case of a woman in her 20s working in customer service, with a BMI of 18.8, within the normal range of 18.5 to under 25.0, who was told at work she was overweight, used such drugs via a self-funded online consultation, continued despite vomiting and was taken to hospital by ambulance and admitted for emergency treatment. [ 1 ]
• The society said being too thin can cause reduced bone mass, menstrual cycle abnormalities and anemia, and urged people to judge whether weight loss itself is appropriate. [ 2 , 3 ]
• Ogawa Wataru, a specially appointed professor at Kobe University, said “the society does not recommend weight loss using off-label drugs.” [ 2 ]

What local media are saying

Timeline, local time

1. 10-03 21:00The Japan Society for the Study of Obesity's statement warning against using drugs such as Mangiaro for weight loss while restricting food or carbohydrates is reported; the society issued it the same day at its academic meeting in Utsunomiya. [ 1 , 2 , 3 ]
2. 10-04 22:08Nikkei reports the statement, including its assessment that side effects may differ for people who are not obese or diabetic, and quotes Kobe University's Ogawa Wataru saying the society does not recommend off-label weight-loss use. [ 2 ]
3. 10-05 17:12Nippon TV News publishes the list of warning symptoms and the advice to stop the drug and promptly consider seeing a doctor, including calling an ambulance for severe cases. [ 3 ]