Dogecoin has been one of the hottest cryptocurrenices of the year, climbing more than 9,000% since the start of 2021 (the S&P 500 is up just 11%). But the danger with investing in the latest meme or trend is that volatility is high, and Dogecoin is no exception. Buying this cryptocurrency can put your portfolio at significant risk; even a tweet from Elon Musk could send your investment spiraling.

If you are craving growth opportunities, then three safer investments to hold in your portfolio right now are Fulgent Genetics (FLGT 0.48%)Palantir (PLTR -0.23%), and PayPal (PYPL 0.64%). All of these companies are growing at impressive rates and could generate some strong (and safe) returns for you in the long run.

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1. Fulgent Genetics

Fulgent Genetics has benefited strongly from a boost in COVID-19 testing over the past year, and management expects to continue to do well this year even as testing volumes slow down. In the most recent quarterly results released May 6, management projected that sales for 2021 would reach $830 million, for a year-over-year growth rate of 97%. During the three-month period ending March 31, the company posted record revenue of $359.4 million, which represented incredible growth of more than 4,500% year over year.

The stock looks especially promising because the company's tests are detecting the different mutations of the coronavirus as they emerge, meaning Fulgent can play a key role in helping to prevent the spread of COVID-19 around the world. Earlier this year, the Centers for Disease Control and Prevention awarded Fulgent Genetics a contract to study the different variants using its next-generation sequencing (NGS) capabilities. NGS is part of Fulgent's core business, which grew at a rate of 115% in Q1, exceeding management's expectations.

Fulgent is also exploring merger and acquisition opportunities to further grow its operations, so there could be even more potential growth for the stock ahead. With cash and cash equivalents of $151.5 million as of the end of March, the company is sitting on nearly double the money it had at the start of the year -- $87.4 million -- putting it in a much stronger financial position should it decide to pursue investment opportunities. 

The pandemic is still far from over, and Fulgent is on track for another strong year in 2021. And with plenty of time to find an acquisition or another avenue to help grow its business, this looks to be a terrific growth stock to consider adding to your portfolio today.

2. Palantir

Data and analytics company Palantir is also coming off a great quarterly performance. On May 11, the company released its first-quarter results for the first three months of 2021. Sales of $341.2 million represented an increase of 49% year-over-year. Palantir makes for an attractive growth stock because it offers both growth and stability, as government customers make up the bulk of its revenue. Last quarter, sales from that segment totaled $208.4 million, up 76% from the prior-year period to account for 61% of total revenue. A year ago, that area of its business represented 52% of sales.

The company is projecting that sales growth will slow to 43% next quarter, but what's promising is that until 2025, management expects the company's annual revenue to rise at a rate of 30%.

Palantir's data solutions can serve many different industries, and that's why the stock offers so much promise. Just in 2021, Palantir has signed (or expanded) deals with a mining company (Rio Tinto), a global manufacturer (3M), and a business involved in automotive technology (Faurecia).

With a wide range of applications for its services and many government customers, Palantir offers investors an excellent mix of safety and growth.

3. PayPal

If you are intent on getting some exposure to cryptocurrencies, then digital payment company PayPal might be a great option. The company now allows U.S. customers to use cryptocurrencies as a funding source. And in March it also announced it was acquiring Curv, a digital asset security company, to help manage crypto holdings.

By allowing people to buy and sell cryptocurrencies on its platform, PayPal can expand its already strong user base. In its most recent results, released May 6 for the period ending March 31, the company reported a 21% year-over-year increase in the number of active accounts to 392 million. And revenue of more than $6 billion represented an increase of 31%. PayPal also increased its guidance by one percentage point, now projecting revenue for fiscal 2021 to rise by 20% to approximately $25.8 billion.

With cryptocurrencies rising in popularity this year and COVID-19 pushing people away from using physical cash, PayPal has a couple of promising growth opportunities on the horizon that could make it a hot investment for many years to come.