Investors looking to capitalize on the growing popularity of medical marijuana may want to consider buying shares of GW Pharmaceuticals (NASDAQ:GWPH). While the company may not want to refer to itself as a cannabis stock, it's definitely benefiting from the soaring sales growth of its drug Epidiolex. The first and only drug based on cannabidiol (CBD) that's been approved by the Food and Drug Administration in the U.S. thus far, Epidiolex has helped put the company on the map.

The stock had been up more than 90% this year before a big market correction sent many cannabis and cannabis-related stocks down over the past several months, as investors instead opted for less risky investments. However, GW Pharmaceuticals is not nearly as risky as other marijuana stocks, and it could be poised for significant growth.

Last month, the company got the news that Epidiolex would be approved in Europe as a treatment option for certain forms of epilepsy.

Epidiolex can be sold to 28 more countries

The approval opened not a door, but floodgates, to even more growth for the company. GW has just been scratching the surface in the U.S. market and it now has the ability to grow in Europe as well. The company isn't wasting any time; GW Pharmaceuticals CEO Justin Gover spoke with Jim Cramer of CNBC recently, telling him: "We'll be launching these countries over the next year or two." GW is even hoping for products to start being sold in multiple European countries before the year is over.

Europe at night, seen from space

IMAGE SOURCE: GETTY IMAGES.

The medical marijuana market is a great growth opportunity in Europe, where it's still fairly small. According to data collected by Rolling Stone, the CBD market in Europe is expected to reach $1.7 billion in 2023, which is more than quadruple the estimate for 2019 -- $416 million.

With the European market still in its early growth stages, it's an optimal time for GW to establish a leadership position. The more success that Epidiolex has in both the U.S. and European markets, the better its chances for further growth, as patients and doctors are convinced of its effectiveness.

Why investors should be excited

Even before the news of GW receiving European approval, the stock was looking very promising. In the company's most recent quarterly earnings report, sales had reached $71 million, up from just $3 million in the prior year. With Europe now in the mix, those numbers could get a whole lot bigger a whole lot faster. And while there's negative press surrounding vaping and the recreational market, GW presents a much safer option for investors, not being exposed to those risks.

With GW's stock price dropping 35% over the last three months, investors have the ability to buy back in at prices that were last seen in January -- before the impressive quarterly results and before news of the European approval. While the stock is trading at a premium of 25 times sales today, it could be well worth it, given the massive opportunities that the company now has on two continents.