Weight loss drugs have taken the pharmaceutical and medical communities by storm. Not only are the companies behind the medications struggling to keep up with global demand, but reports are emerging that the drugs could alleviate health problems beyond obesity. Studies have found that the medications, known as GLP-1 drugs, could help with ailments ranging from sleep apnea to kidney disease.

The broad applications have led some analysts to label these medications “miracle drugs.” For the companies behind them, the weight loss treatments are expected to lead to billions of dollars in sales, windfall profits, and a big boost to their stocks. Already, the pharma companies behind the drugs are seeing their share prices double on expectations for current and future sales. Some on Wall Street are saying that they could become the biggest selling prescription drugs of all time.

Here are the top three weight loss drug stocks to buy for huge gains.

Eli Lilly and Co. (LLY)

Eli Lilly’s (NYSE:LLY) weight loss drug Zepbound has only been commercially available in the U.S. for a little more than six months. But it is already having a big impact on the company’s financial results. The pharmaceutical giant reported first-quarter EPS of $2.58 versus $2.46 that was expected on Wall Street. Revenue missed analyst targets, coming in at $8.77 billion compared to $8.92 billion that was forecast. Despite the miss, sales were up 26% year-over-year.

Management at Eli Lilly said they are seeing growing sales of Zepbound. The latest earnings included the first full quarter of Zepbound sales. The drug, which was approved by U.S. regulators last fall, reported $517.4 million in Q1 sales. The company continues to struggle with shortages of Zepbound in the U.S. as it ramps up production to meet red hot demand. Some analysts have forecast that Zepbound could post $1 billion in sales in its first year on the market, and that it might become the biggest selling drug of all time.

LLY stock has doubled in the last 12 months.

Novo Nordisk (NVO)

Danish pharmaceutical company Novo Nordisk (NYSE:NVO) has its own blockbuster weight loss drug called Wegovy. And Novo Nordisk has just been granted approval to sell it in China, one of the world’s most populous countries with 1.4 billion citizens. The China approval opens a huge new market for Wegovy and the company behind it. More than half of China’s population is considered overweight, according to data from the country’s National Health Commission.

Novo Nordisk’s Ozempic diabetes medication was approved for use in China in 2021, and that drug’s sales doubled last year. Wegovy will initially be available to people in China who have a body mass index that indicates obesity and to people who have medical conditions related to being overweight. At the same time that Wegovy was approved for use in China, Novo Nordisk announced that it is spending $4.1 billion to build a new manufacturing plant in North Carolina that will help it keep up with demand for the drug.

NVO stock is up 83% over the past year.

Viking Therapeutics (VKTX)

Viking Therapeutics (NASDAQ:VKTX) is a newer entrant in the weight loss drug market. The company’s shares have gained 157% so far this year after trials of its weight loss candidate, currently known as “VK2735,” showed promise. Despite trailing both Eli Lilly and Novo Nordisk and being late to the weight loss drug party, Viking’s medication is viewed by analysts as a legitimate contender in the field.

Some analysts on Wall Street have forecast that Viking’s weight loss drug could generate sales of more than $10 billion by 2035. That kind of hype has VKTX stock running higher. The company’s share price has also been marching upwards on expectations that a bigger pharmaceutical company such as Pfizer (NYSE:PFE) might buy Viking Therapeutics or partner with it to gain access to its weight loss drug.

Time will tell what happens to Viking Therapeutics, but excitement around the company and its weight loss medication are building.

On the date of publication, Joel Baglole held a long position in LLY. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.