Novo Nordisk (NVO 0.01%) is the company behind diabetes and weight-loss treatments Ozempic and Wegovy. Business has been booming as demand for those drugs has left the company in a rush to add capacity so that it can fill orders. The stock has made for a hot buy this year, already rising 23% since the start of January.

But just how much would you have made if you had invested in the stock at the start of 2020? Let's have a look.

Where the stock was in January 2020

On Jan. 2, 2020, shares of Novo Nordisk opened at a price of $58.31. The healthcare stock was coming off an already strong year in 2019 during which its share price rose by 26%. But even if you had bought shares of the stock back then, you would still be sitting on some massive gains right now.

Since 2020, shares of Novo Nordisk have risen by around 190%. By comparison, the S&P 500 index has increased just 27% over the same time frame. The healthcare company also pays a dividend that yields around 1%, so your total returns would have been even higher.

A $10,000 investment in 2020 would be worth over $31,000 today, when including those payouts, for a return of 210%. If you invested in the S&P, however, then your investment would be worth just $13,500 right now.

Why the stock has been soaring

Novo Nordisk has been a good buy for multiple years, but things have really started to soar in just the past year (its total returns during that stretch are over 60%) as the hype and popularity of Wegovy and Ozempic has taken off.

Another good example of that is WW International, also known as WeightWatchers, which saw its share price jump simply on news that it will be able to prescribe Wegovy and Ozempic to its members. Many celebrities, including Elon Musk, have also touted the effectiveness of the drugs, which has helped generate more interest, and it's not uncommon to see Ozempic and Wegovy trending on social media.

Ozempic is only approved to treat diabetes in the U.S. but that hasn't stopped customers from using it anyway as it's a lower-dose version of semaglutide, the active ingredient in Wegovy -- which is approved for weight loss. In clinical trials, Wegovy was able to help people lose about 15% of their body weight.

Due to the strong results and popularity, last year Novo Nordisk generated 26% revenue growth, with obesity care sales doubling. And that trend is not slowing down -- obesity care sales rose 131% during the first three months of this year. The company also noted that it has a second contract manufacturer to produce Wegovy in the U.S., with production already under way.

Is Novo Nordisk still a good buy today?

Novo Nordisk stock is trading around its all-time highs, so investors may be thinking that it's too late to invest, especially with shares of the company trading at a price-to-earnings multiple of 42.

But given the growth potential for the company's diabetes and weight-loss drugs, there could be much more room for the stock to rise, and it wouldn't surprise me if the company's valuation were to eventually hit $1 trillion (versus its current market cap of around $370 billion). 

Even though it may not be a cheap-looking stock right now, Novo Nordisk can still be an excellent investment to add to your portfolio today as there's still plenty of growth on the horizon for the business.