Eli Lilly's weight-loss drug may prevent diabetes — but there's 1 unanswered question

• A 3-year-study of Zepbound and Mounjaro found the GLP-1 drugs can help prevent diabetes.
• The weekly injections cut the risk of developing diabetes by 94% among adults with high blood sugar.
• The drugs also prompted significant weight loss: on average, 12-23% of body weight.

First, these new injectable drugs were meant to treat diabetes. Then, they became approved for weight loss. And now, a new study suggests losing weight with some GLP-1 drugs can also prevent diabetes.

Results from a three-year study of over 1,000 patients, funded by drugmaker Eli Lilly, suggest that taking Zepbound or Mounjaro may reduce the risk of developing diabetes by 94% among patients at risk. Those patients were both overweight and had pre-diabetes — higher-than-normal blood sugar readings put them at greater risk of developing type 2 diabetes in the near future.

"These data reinforce the potential clinical benefits of long-term therapy for people living with obesity and pre-diabetes," Dr Jeff Emmick, senior vice president of product development at Eli Lilly, said in a release.

Patients on the drug lost a lot of weight — lowering their risk of developing diabetes

The weight loss benefits of taking Eli Lilly's dual-agonist drug, (generically called tirzepatide) were profound.

Patients on the highest dose of the drug lost, on average, more than 22% of their body weight in this study, while patients on the lowest dose lost around 15%. Patients in a control group on a placebo jab only lost about 1%.

Weight loss, along with eating healthy and exercising more, is already a well-known strategy for reducing the risk of developing diabetes among people with pre-diabetes.

Hormone-mimicking shots like Zepbound, Mounjaro, Ozempic, and Wegovy make your body feel full with less food; they slow down digestion and improve blood sugar control. Tirzepatide tends to be a more powerful medication than semaglutide (the drug branded as Ozempic and Wegovy from Novo Nordisk), because it acts on two separate hormone receptors (GLP-1 and GIP) rather than one.

The big unanswered question

How long people will need to remain on these drugs is unclear. If someone on Zepbound or Mounjaro loses a substantial amount of weight, to the point that they no longer have pre-diabetes or obesity, can they stop taking their drug?

That is something doctors and researchers can't answer. Studies suggest that most people who do that will rebound, regaining all they've lost, and often more. Plus, insurers tend not to cover a drug that costs more than $1,000 a month for someone without any diagnosable health conditions.

These weekly injectables for weight loss and diabetes are also being tested as prevention and treatment tools for various other conditions including dementia, liver disease, and drug and alcohol addictions.

But it's unclear how often the drugs will be covered by insurance, and whether people will want to deal with common side effects like nausea and gastrointestinal issues for life.