Ozempic Researcher Was "Extremely Alarmed" Over Thyroid Cancer Risk

box of ozempic injectable pens alongside a stethoscope on a white background — Caroline Ruda / Shutterstock

As with starting any new medication, it's important to consider the potential health risks and side effects. While celebrities like Real Housewives stars Emily Simpson and Dolores Catania have praised the weight loss drug Ozempic for its body-slimming superpowers, several A-listers spoke out against the semaglutide injection, calling its side effects unlivable and intolerable.

Abdominal pain, nausea, and diarrhea are some of the most common side effects reported by Ozempic users. However, in Sunny Hostin's case, her constipation became so aggravated that she was taken off the medication entirely. Meanwhile, Sharon Osborne revealed she was "gaunt" after losing too much weight. And actor Stephen Fry had to quit Ozempic because he was "literally throwing up four, five times a day."

Mild gastrointestinal pains are the most discussed side effects among Ozempic users, but the drug's ramifications can vary from patient to patient. Factors such as underlying health issues, other medications, and even genetics can play a role in how a weight loss medication like Ozempic can affect you—in both the short and long term.

In a podcast interview with journalist Sean Illing, Ozempic user-turned-researcher Johann Hari revealed he was "extremely alarmed" to learn that one of the potential downsides of taking Ozempic injections is that it can significantly increase your risk of thyroid cancer.

Hari referenced a 2023 study published in the journal Diabetes Care, in which researchers "found increased risk of all thyroid cancer and medullary thyroid cancer" in Ozempic patients with diabetes after one to three years of treatment. (It's important to note that Ozempic is first and foremost used to treat Type 2 diabetes; however, it's also known to help with weight loss.)

"There's a brilliant French scientist called Jean-Luc Faillie, and what he looked at was a very large group of diabetics who use these drugs, and then he looked at a comparable group of diabetics who were very similar in every other way but didn't use these drugs," Hari explained on The Gray Area podcast, which dropped May 13.

Hari then revealed, "One thing he and his colleagues calculated is that these drugs, if they're right, increase your risk of thyroid cancer by between 50 to 75 percent."

Before continuing, Hari noted that it's paramount to understand what exactly this statistic means.

"That doesn't mean if you take the drug, you have a 50 to 75 percent chance of getting thyroid cancer," he explained. "What it means is that if you take the drug—if [Faillie] is right, and this is highly disputed—whatever your thyroid cancer risk was at the start, that risk will increase by between 50 to 75 percent."

For instance, if thyroid cancer runs in your family, your likelihood of developing it goes up by potentially 75 percent after taking Ozempic.

The thyroid is a vital functioning gland in the human body that "makes hormones that help regulate your metabolism, heart rate, blood pressure, and body temperature," per the American Cancer Society. The most common types of thyroid cancer are called Papillary cancer and Follicular cancer.

The American Cancer Society estimates that 44,020 people will be diagnosed with thyroid cancer in 2024.

"I was extremely alarmed," Hari said about his findings.

However, Hari noted that obesity can also lead to certain types of cancer. So, if an Ozempic user can reduce their chances of developing cancer by losing excess weight, it could still be considered a win.

"Lots of other scientists said to me, 'Well, look, even if that's right, you've got to compare it to what would happen to your cancer risk if you just remain obese.' And actually, I was stunned by the evidence about the cancer risk just from being obese. One of the biggest preventable causes of cancer in the United States and Britain is obesity," Hari explained.

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.

Emily Weaver Emily is a NYC-based freelance entertainment and lifestyle writer — though, she’ll never pass up the opportunity to talk about women’s health and sports (she thrives during the Olympics).Read moreFiled UnderMedicine • NewsSources referenced in this article