K.Will says he used Mounjaro, exercise and diet

K.Will discussed a recent weight-loss effort on SBS entertainment program My Little Old Boy, which aired on July 5. He said he went on a diet last year ahead of a year-end concert and used Mounjaro along with exercise and a diet plan.

He said he had 'lost more than 10kg' and that he has now 'put about 4~5kg back on.' The source said Mounjaro, the medication he mentioned, is an injectable obesity treatment developed by U.S. pharmaceutical company Eli Lilly.

The source described Mounjaro as a dual-action drug that works on both GLP-1 and GIP receptors. According to the source, GLP-1 promotes insulin secretion and suppresses glucagon, a hormone that raises blood sugar, while GIP also helps insulin secretion and promotes fat metabolism and energy expenditure.

The source said this mechanism keeps food from passing through as quickly and sends satiety signals to the brain, suppressing appetite. It also said side effects can include gastrointestinal symptoms such as nausea, vomiting, diarrhea, constipation and indigestion, while gallstones, cholecystitis and pancreatitis may occur in some cases.

The source added that dieting with Mounjaro can reduce muscle as well as fat. It said lower muscle mass can reduce basal metabolic rate, make weight maintenance more difficult and increase the risk of reduced physical function and falls over the long term.

The source cited an analysis by a research team led by Professor Sam West at the University of Oxford in the U.K. of 37 studies related to obesity treatments including Wegovy, Mounjaro and Saxenda. According to that analysis as cited by the source, after stopping medication, the medication-treatment group regained weight at an average monthly rate of 0.4kg, about 4 times faster than the non-medication-treatment group. The source said balanced meals and regular exercise should be combined rather than relying on medication, with enough protein such as beans, tofu and fish and strength training at least 2~3 times a week. It added that if side effects such as nausea or vomiting interfere with daily life, the dose should be adjusted after consultation with medical staff.

I went on a diet last year ahead of my year-end concert. I did Mounjaro, exercise and diet, all of it.

I lost more than 10kg, and now I have put about 4~5kg back on.