Pfizer (PFE 0.55%) and Novo Nordisk (NVO 0.84%) are two top pharmaceutical companies that are pursuing growth opportunities. Pfizer is looking to build up and diversify its business as its COVID revenue diminishes. Novo Nordisk's strategy centers around a fast-growing product in Wegovy. The business isn't as diverse as Pfizer's, but the upside Wegovy possesses could make up for that. Which of these stocks should growth investors buy today?

The case for Pfizer

Pfizer has been raking in the profits and free cash flow from its COVID-19 vaccine and pill. Even though that likely won't be a source of growth for the business moving forward, the company can still reap the rewards. As of July 2, Pfizer had cash and investments totaling nearly $45 billion.

With plenty of resources to tap into, the company is in a great position to invest in its future growth. And Pfizer has already been busy with acquisitions in recent years, including the following deals:

  • Seagen (pending)
  • Biohaven Pharmaceuticals (closed October 2022)
  • Global Blood Therapeutics (closed October 2022)
  • ReViral (closed June 2022)
  • Arena Pharmaceuticals (closed March 2022)
  • Trillium Therapeutics (closed November 2021)

Pfizer's ultimate goal is to add $25 billion in revenue by the end of the decade, which will help offset losses in exclusivity from some of its top drugs, including blood clot medication Eliquis.

A potential wild card to consider is danuglipron, which is a weight-loss drug that Pfizer has been developing and that in clinical trials has shown comparable results to that of Ozempic, although at a much higher dosage. If danuglipron proves it can be a viable competitor in the weight-loss market, that could significantly improve Pfizer's long-term growth prospects.

The case for Novo Nordisk

Novo Nordisk's growth prospects center heavily around its obesity treatment, Wegovy. While Ozempic is more popular and associated with weight loss as well, it's a diabetes drug that people have been taking because it has also been effective in reducing body weight. As Wegovy becomes more readily available, however, some of the demand for Ozempic will likely shift toward Wegovy.

The company has been launching Wegovy in new markets, most recently in the U.K. and Germany. While its presence is growing, it's still only available in five markets, including the U.S., Norway, and Denmark, its home market. The big impediment at this stage is producing enough supply of Wegovy to meet demand. Sales of Wegovy have soared 367% through the first half of the year, and that's still scratching the surface of the drug's potential.

An oral version of Wegovy could also be available in the near future. That may be more appealing to patients than an injection, paving the way for even more growth. Researchers believe that Wegovy can also help prevent heart attacks. If that's the case, then it may reach an even wider group of patients.

Analysts have projected that Eli Lilly's weight-loss treatment Mounjaro could generate $68 billion in annual revenue at its peak, according to a recent forecast. Mounjaro may be a more promising treatment than Wegovy as patients have lost more weight than those who have taken Wegovy, but it's indicative of just how massive a market there may be out there for a good weight-loss treatment. Even if Wegovy is the second-best option available, it may still generate tens of billions in revenue for Novo Nordisk.

Growth investors should go with Novo Nordisk

Pfizer is working on growing its business, but its top and bottom lines may not be a whole lot higher in the near term due to the headwinds it is facing, including a loss in COVID revenue and losses in exclusivity from some of its key drugs. Novo Nordisk faces a much more promising outlook as this is a business that looks to be on a path toward significant revenue growth ahead.

For growth investors, Novo Nordisk is hands-down the better buy right now.