Eli Lilly (LLY 1.19%) is the top healthcare company in the world. Investors have been paying a big premium for the business and its future growth, propelling it to all-time highs this year. Is there still room for the stock to rise even higher, or is it approaching a peak?

Lilly reported 28% revenue growth last quarter

This past Tuesday, Eli Lilly posted its most recent quarterly results for the last three months of 2023. Revenue rose 28% to $9.4 billion from the same period last year.

Mounjaro, the company's diabetes medication, has taken over the top spot as the company's top-selling drug, unseating Trulicity. Mounjaro's sales last quarter totaled $2.2 billion (versus just $279 million a year ago), while Trulicity came in at under $1.7 billion, its sales declining by 14% year over year.

The stronger top-line results helped Eli Lilly also achieve solid profit growth, with its net income rising by 13% to $2.2 billion.

Expecting strong growth again in 2024

Mounjaro and recently approved Zepbound (essentially the same drug, just approved specifically for weight loss) will be key pieces of Eli Lilly's long-term growth. And this year, the company is expecting another solid performance.

Eli Lilly projects that in 2024 its revenue will total between $40.4 billion and $41.6 billion. At the midpoint, that would be 20% higher than the company's revenue in 2023. That's the same growth rate as Eli Lilly generated in the past year.

The stock trades at over 120 times earnings

For 2023, Eli Lilly reported diluted earnings per share (EPS) of $5.80, down 16% year over year. Based on its share price of around $700, that would put its price-to-earnings multiple at about 121.

This year, the company is expecting its EPS to come in between $11.80 and $12.30. At the high range, that would mean investors are paying approximately 57 times the company's 2024 earnings -- if Eli Lilly hits the high end of that range. At the low end, the multiple would be more than 59.

This calls into question whether investors are pricing in too much future growth for the business. The consensus analyst price target for the healthcare stock is just under $590 -- Eli Lilly is well above that mark right now and faces a downside risk of more than 16% based on that target. That doesn't mean it will fall to that level, but it does underscore how quickly it has been rising, as it has blown past analyst price targets.

Eli Lilly is entering a new era, where Trulicity is no longer the top drug for the company. Instead, its weight-loss and diabetes products, Mounjaro and Zepbound, will be cornerstones for the company. But there's some risk there as investors may be expecting too much from these products too quickly. There's also the potential for other drugs to come in that steal market share, perhaps if they come with fewer side effects or prove to be more effective.

Is Eli Lilly stock still worth buying today?

Eli Lilly is an expensive stock, but if Mounjaro and Zepbound prove to be the real deals and bring in tens of billions of dollars for the business, it will be hard to argue with today's valuation, as the stock could look cheap in the future. Based on the strong results and promise the products hold, it's hard not to like Eli Lilly in the long run.

There's still much more growth out there for the company, and the significant profits Eli Lilly generates could help it pursue other opportunities in the years ahead. The healthcare stock may be expensive today, and that could hinder its returns in the short term. But in the long run, this can still be an exceptional investment to hang on to from here.