Millions of people have taken or are using one of nine approved weight-loss medications. But there's still a lot of confusion about their safety and potential side effects.

So Mayo Clinic researchers decided to take a look at data on the benefits and risks of three of them: liraglutide (Saxenda), semaglutide (Wegovy), and tirzepatide (Zepbound).

The researchers reviewed available data and found that Zepbound (approved and available for the past 18 months) resulted in an average weight loss of 18% of users' body weight; Wegovy (in use for three years) delivered 12% weight loss; and Saxenda (around for 10 years) led to 5% loss.

In addition, their article in the journal Obesity Pillars notes that Wegovy can reduce a user's risk for a nonfatal heart attack, stroke, or death from other cardiovascular issues by up to 20%.

As for side effects ... all three medications may cause gastrointestinal problems, but most are mild to moderate and fade over time.

The most serious side effects (which are not common) included pancreatitis and inflammation of the gallbladder and bile ducts — and those mostly happen to people who take higher doses for a longer time.

We support the use of these medications, but you should not get them from online doctors or shady internet sources. Those often-fake versions have been known to cause hypoglycemia and seizures because they contain insulin instead of the weight-loss drug.

For more help achieving a healthy weight — and not gaining it back — check out our book "YOU On a Diet."