Better Growth Buy: Eli Lilly vs. Viking Therapeutics

By Adria Cimino | July 07, 2025, 3:45 AM

Key Points

  • Eli Lilly is a leader in the weight loss drug market, generating blockbuster revenue.

  • Viking Therapeutics recently launched a phase 3 trial for its weight loss candidate -- and could have a promising future in the market.

Though you may think "tech stocks" when someone mentions growth, you actually can find growth stocks throughout a wide variety of industries. Even those like pharmaceuticals, often known for the steadiness of their earnings, may, through certain specialty areas, offer you the opportunity for explosive growth. And today, the perfect example is weight loss drugs.

Today's $28 billion weight loss drug market is on track to reach nearly $100 billion by 2030, according to Goldman Sachs Research, offering companies in the space an extremely solid opportunity over the next several years and likely beyond.

Two names that have been making headlines in this field are Eli Lilly (NYSE: LLY) and Viking Therapeutics (NASDAQ: VKTX). The former is a current leader, already selling two blockbuster drugs prescribed for weight loss, and the latter is an up-and-coming player, with a candidate in late-stage trials. Which is the better growth buy today? Let's find out.

An investor leans against a desk and studies something on a tablet.

Image source: Getty Images.

The case for Eli Lilly

Eli Lilly shares weight loss drug market leadership with fellow big pharma player Novo Nordisk. They each commercialize two drugs prescribed to people aiming to lose weight and have brought in billions of dollars in annual revenue. Here, I'll focus on Lilly.

The company's drugs, Mounjaro and Zepbound, are actually the same compound, tirzepatide. But it's sold under the name Mounjaro for type 2 diabetes and under the name Zepbound for weight loss. The drug acts by stimulating hormonal pathways involved in the control of blood sugar levels and appetite. Thanks to the efficacy of tirzepatide, demand has soared, even surpassing supply until Lilly expanded its production capacity.

But Lilly isn't sitting still in the area of weight loss. The company also is developing other drug candidates that may improve upon tirzepatide. The closest to market right now is orforglipron, Lilly's oral candidate for weight loss that recently delivered positive phase 3 trial results. If approved, it would be the only oral weight loss drug of its class that doesn't require strict food and water restrictions. Lilly aims on applying for regulatory review by the end of this year.

All of this could result in more growth for Lilly this year and well into the future.

The case for Viking Therapeutics

Viking Therapeutics is a biotech company specializing in metabolic conditions, and it's made great progress with its obesity drug candidate, VK2735. The potential drug, in subcutaneous form, recently entered a phase 3 trial, and an oral form is involved in a phase 2 trial. These candidates are in the same class as tirzepatide, so work in the same way.

Investors have shown their excitement about Viking's program in the past: When the company reported positive phase 2 data for the subcutaneous VK2735 last year, the stock soared more than 120% in one trading session. The stock hasn't maintained those gains, but the movement shows that investors are interested in the program -- and more good news ahead could boost the stock again.

Now you might wonder why investors are so excited about Viking if there already are other successful weight loss drugs on the market -- and Lilly even is likely to reach commercialization with an oral weight loss drug ahead of Viking. This is because demand is high, and this is set to continue, so there is plenty of room for more than a couple of companies to succeed in the space. Investors also have speculated about the idea of a big pharma company acquiring Viking to get in on this high growth market.

Should you buy the pharma leader or the biotech challenger?

Lilly has the first-to-market advantage, is closer to the finish line with an oral candidate, and already is generating major revenue from its weight loss portfolio. Viking, if successful through clinical trials, could carve out market share and deliver major revenue growth down the road -- or the company could be acquired, offering investors another way to potentially gain.

Each company offers certain advantages. Now let's answer our question. If all goes well for Viking, it could represent the better growth buy as, starting from zero product revenue today, this player could see revenue soar if and when it brings a weight loss drug to market. And we've seen that Viking's stock price is very reactive to news, meaning the stock could skyrocket in such a scenario. But, if you go the Viking route, you should be comfortable with risk as uncertainty remains: The company hasn't yet reached the finish line with a product.

If you're more of a cautious investor, though, don't worry. You may opt for Lilly as, even though it's climbed 140% over the past three years, it still could have plenty of room to run over the long term thanks to this weight loss drug growth story.

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Adria Cimino has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Goldman Sachs Group. The Motley Fool recommends Novo Nordisk and Viking Therapeutics. The Motley Fool has a disclosure policy.

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