The US Food and Drug Administration (FDA) on Wednesday announced it had approved Eli Lilly's highly anticipated weight loss drug Zepbound.

It is the latest entrant in a field of powerful new obesity medicines including Novo Nordisk's successful Ozempic and Wegovy, and has been predicted by analysts to become a bestseller.

Administered by weekly injection, Zepbound has been indicated for patients who are obese or overweight patients with at least one weight-related condition, such as high blood pressure, type 2 diabetes or high cholesterol.

"Obesity and overweight are serious conditions that can be associated with some of the leading causes of death such as heart disease, stroke and diabetes," said the FDA's John Sharetts in a statement.

"In light of increasing rates of both obesity and overweight in the United States, today's approval addresses an unmet medical need."

Zepbound's active ingredient tirzepatide was previously approved under the trade name Mounjaro, a diabetes control drug also made by Eli Lilly.

In a clinical trial involving more than 2,500 adults, people taking Zepbound in addition to dieting and exercise lost on average 48 pounds (22 kilograms) when given the highest allowed dose, and 34 pounds on the lowest dose, compared to seven pounds on placebo.

At the start of the trial, the average weight was 231 pounds.

Around 70 percent of American adults are obese or overweight, and losing five to ten percent of body weight through diet and exercise has been linked to a reduced risk of cardiovascular disease.

"New treatment options bring hope to the many people with obesity who struggle with this disease and are seeking better options for weight management," said Joe Nadglowski, president and chief executive officer of the Obesity Action Coalition, in a statement.

Zepbound comes with a high list price of $1,059.87, which may limit the number of people who can receive it since insurance companies often do not cover weight loss medications. Medicare, the state subsidized insurance for the elderly, is barred from covering it.

Nevertheless, Eli Lilly said in a release that people covered by insurance could pay just $25 for a 1-month or 3-month prescription.

Despite their burgeoning popularity, the new class of weight loss drugs known as GLP-1 receptor agonists have been found to heighten the risk of certain severe gastrointestinal problems, according to a large study published last month in the Journal of the American Medical Association (JAMA).

These include stomach paralysis, pancreatitis and bowel obstruction.

The FDA said Zepbound's known side effects included nausea, diarrhea, vomiting, constipation, abdominal discomfort and pain, injection site reactions, fatigue, allergic reactions, burping, hair loss and gastroesophageal reflux disease.

It has been found to cause thyroid C-cell tumors in rats, but it is unknown whether the same is true for humans.