Singer K.Will stopped taking Mounjaro after losing 14 kilograms — then his hair started falling out

Singer K.Will, 44, said he stopped taking the obesity drug Mounjaro after losing 14 kilograms and began experiencing hair loss as a side effect.

A video titled "K.Will Gets His First Hair-Loss Diagnosis and Scrambles for Easy Hair Care Tips" was posted Wednesday on his YouTube channel "Hyeongsuneun K.Will."

In the video, K.Will said he had recently stopped taking Mounjaro, citing hair loss as one of the reasons. "One of the reasons I stopped is that as the weight came off, I could see my hair falling out — things started happening that had never happened before," he said.

"My hair was already on the thin side, but it got even thinner," he added. "It didn't look like it fell out gradually — it looked like it all came out at once."

He said he felt disheartened when sweat-soaked hair after workouts made the top and sides of his head look even more sparse. "Before, I had so much hair that sweating was never an issue," K.Will said. "I was heading to musical rehearsals after working out, and my hair on the sides was wet — musical actor Jeong Yeong-ju came over and touched my hair. I think it was because it looked thin."

He added, however, that his hair loss was not yet at a worrying level. "It's not bad enough to be seriously concerned about, but I do find myself thinking I need to take care of it," he said.

K.Will visited a head spa clinic to check the condition of his scalp and was caught off guard when he received a "stage-one hair loss" diagnosis. He said he felt some relief upon learning it was not the typical M-shaped or O-shaped pattern baldness, but admitted, "I do have this frightening thought that it might all just fall out."

K.Will revealed in a February YouTube video that he had lost 14 kilograms in about two months by combining Mounjaro injections with diet and exercise.

Meanwhile, research has found that GLP-1 drugs — widely used as obesity treatments under brand names such as Wegovy and Mounjaro — can raise the risk of hair loss by as much as 68 percent.

According to a study published last month in the British Medical Journal by researchers at the University of Pennsylvania, people taking GLP-1 drugs faced a 37 percent higher risk of hair loss than those taking SGLT-2 diabetes medications, and a 68 percent higher risk compared with those on DPP-4 diabetes drugs.