Investing in Dogecoin (DOGE 2.32%) has undoubtedly made many people rich this year, but it's been far from a safe buy. If you invested at the peak, when it was worth around $0.74, you would have lost more than half your money since then. Rather than investing in risky cryptocurrencies like Dogecoin, investors should instead consider buying shares of companies that are bullish on the blockchain technology (which digital currencies use).  Blockchain can impact virtually every industry, changing how businesses operate, by decentralizing information and making the transfer of data more secure and efficient.

Three growth stocks that have shown interest in blockchain are Quest Diagnostics (DGX 0.43%), Square (SQ 3.38%), and Tesla (TSLA 2.99%). Here's why they could be good buys. 

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1. Quest Diagnostics

Diagnostics and research company Quest Diagnostics isn't your typical blockchain stock as it doesn't actively promote the technology. However, the company is part of a coalition of healthcare companies that are involved in the Synaptic Health Alliance, whose objective "is to create a blockchain-powered platform that enables a culture of innovation, removes friction, and solves the shared challenges impacting constituents across healthcare today." Through blockchain technology, the group believes significant efficiencies can be achieved in sharing information and automating tasks. According to Synaptic's data, more than $2 billion is spent across the healthcare industry simply "chasing and maintaining provider data." 

For a company like Quest that needs to communicate test results to patients and providers in a quick and secure way, blockchain technology could have many applications for its business. Now, this doesn't mean that Quest is a stock you can expect to go up on positive news relating to blockchain nor will it soar if the price of Bitcoin (BTC 2.69%) is surging. However, it stands to benefit from more widespread use of blockchain technology across the industry. And Quest is a decent growth stock as well.

The company released updated guidance this month for 2021, upgrading its forecast in the wake of the delta variant and surging COVID-19 case numbers. Previously, Quest was expecting revenue of between $9.5 billion and $9.8 billion for the year but now it expects revenue could top just over $10 billion, which would represent year-over-year growth of 7%. While COVID-19 testing has given the company's financials a boost, during the first six months of 2021 Quest has also generated growth across all its testing segments, including routine clinical testing (its largest business unit), which rose by 24% to $2.2 billion.

Quest is a solid investment and with the company showing an interest in blockchain technology, it's an option that Dogecoin fans should consider.

2. Square

Even more engrained in crypto and blockchain technology is fintech company Square. Through the company's Cash App, users can buy and sell Bitcoin. And Bitcoin-related revenue has been a big part of Square's business. Over the past two quarters, it is responsible for more than $6.2 billion in sales for the company -- that's close to two-thirds of the $9.7 billion that Square reported for the six-month period ending June 30.

But Square is going even further. Earlier this year, CEO Jack Dorsey announced that the company would also be launching a new business unit, known only as "TBD" -- which may suggest a more formal name could still be on the way. But regardless of what it's called, the unit's focus is on decentralization of financial services, where Bitcoin will play a key role.

Square's business has become heavily dependent on Bitcoin for growth, and if you're bullish on the cryptocurrency or just blockchain technology as a whole, this is a stock that could give you some terrific exposure.

3. Tesla

The biggest promoter of Dogecoin is undoubtedly Tesla CEO Elon Musk, who has shown the power to move the cryptocurrency through just a single tweet. Investing in the electric vehicle maker's stock can be another way for Dogecoin fans to benefit from the growing popularity of blockchain technology.

Although Musk has wavered in the past on whether his company would accept Bitcoin for car payments, he does appear inclined to do so. After first claiming he would, only to later renege and say that mining for the cryptocurrency wasn't environmentally friendly, he suggested in July that the company would "most likely" end up accepting Bitcoin.

Tesla itself bought $1.5 billion worth of Bitcoin earlier this year. One of the dangers of this, however, is that it can lead to some volatility in the company's financials. For the period ending June 30, Tesla recorded a $23 million impairment charge related to Bitcoin. Although that's a drop in the bucket compared to the more than $1.1 billion in net income Tesla posted for the quarter, it's still a risk that investors need to be aware of given the significant volatility that can sometimes accompany cryptocurrencies, especially if the company increases its exposure to Bitcoin.

If you're a fan of cryptocurrency or blockchain technology in general, then Tesla is definitely a stock you'll want in your portfolio as it isn't shying away from exposure to digital currencies.