'Almost had a heart attack': god's Park Jun-hyung reveals how vitamin overdose left him with arrhythmia

Park Jun-hyung, the eldest member of dance group god, has shared how taking excessive amounts of vitamin D3 during the COVID-19 pandemic left him with an irregular heartbeat.

Park appeared Saturday on singer DinDin's YouTube channel "DinDin is DinDin," where he recounted the experience.

He said anxiety over catching COVID-19 had led him to avoid going outside almost entirely. During that period, he began taking large doses of vitamin D3 — and eventually noticed something was wrong with his body.

"During COVID-19, Julien Kang told me I absolutely had to take vitamin D3 and to take five 1,000 IU tablets a day," Park said. "I thought I should take even more, so I was taking 15,000 IU a day."

"After a while, I was climbing a hill with a backpack on and I got short of breath and my arm went numb. I thought I was having a heart attack, so I went to a cardiac clinic — and they told me I had developed arrhythmia," he said.

When he went in for a cardiac blood test, Park said the doctor asked whether he drank a lot of milk. "I told him I was taking 15,000 IU of vitamin D3 a day, and he said my levels were 10 times higher than a normal person's."

"Apparently, taking that much throws off your calcium metabolism," Park added. "I took that much for a year and it wrecked my body."

Vitamin D is widely recognized as essential for bone health and immune function. But as Park's case illustrates, prolonged excessive intake can cause serious side effects.

The most common complication of vitamin D overdose is hypercalcemia, or abnormally high calcium levels in the blood. Because vitamin D promotes calcium absorption in the intestines, taking too much can push blood calcium to dangerous levels. Symptoms include nausea, vomiting, loss of appetite, constipation, excessive thirst, frequent urination and dehydration.

Sustained hypercalcemia also puts significant strain on the kidneys, raising the risk of kidney stones, impairing kidney function and, in severe cases, potentially leading to acute kidney failure. Neurological symptoms such as fatigue, lethargy, difficulty concentrating and confusion have also been reported, as have muscle weakness, muscle pain and bone pain. In more serious cases, the condition can progress to cardiovascular complications including arrhythmia and calcification of blood vessels and soft tissue.

Experts generally recommend a daily vitamin D intake of 600 to 800 IU for adults, with an upper limit of 4,000 IU. While high-dose supplementation is sometimes prescribed temporarily under medical supervision, taking 10,000 IU or more per day over an extended period without monitoring significantly increases the risk of overdose.