The healthcare industry is a great place to invest because it can give investors some safe stocks to buy and hold. Health stocks are normally not very volatile and they can be profitable investments to put in your portfolio for many years.

One criticism is that they may lack growth opportunities. However, that's not the case with the two stocks below, which have been growing sales and are still attractive value buys today.

1. Biogen

Biogen's (NASDAQ:BIIB) top line reflected more than $14.2 billion in sales over the past 12 months as it looks to be on track for another improved year. In 2018, sales of $13.5 billion rose 9.6% from the prior year and 2017's revenue of $12.3 billion increased by 7.2% from 2016. Those aren't the sky-high growth numbers you'll find with the latest and greatest tech stocks, but they're still solid revenue figures in an industry where growth can be hard to come by.

One area where Biogen can see a lot more growth is with aducanumab, its Alzheimer's drug. Analysts are expecting the company to submit it to the Food and Drug Administration (FDA) for approval "within weeks." If approved, the drug can significantly improve Biogen's sales. Analysts are projecting that aducanumab could generate close to $4 billion in revenue annually as early as 2024.

People working in a lab.

Image source: Getty Images.

However, it's still a bit of a question mark as the company had mixed results from the drug in 2019 and even looked to abandon it at one point. But it is going ahead with seeking approval for the drug after discussions with the FDA. 

From a value standpoint, the stock ticks a lot of the boxes for price-conscious investors. With a forward price-to-earnings multiple of less than nine and a PEG ratio of one, the stock is a very good buy when factoring in the future growth of the company. 

2. AbbVie

AbbVie (NYSE:ABBV) is another stock that's been showing nice growth of late, with sales up 16% in 2018 and 10% the year before that. That growth has largely come through acquisitions, which AbbVie doesn't always have a great track record with. One of its more high-profile acquisitions, of Botox-maker Allergan, is due to close early this year. And while that will certainly diversify the company's sales and inject more growth, its execution will be heavily scrutinized by investors given its hefty $63 billion price tag. 

But there's reason to be positive: Despite all the noise and acquisitions, AbbVie has found a way to make it all work, consistently reporting net income of more than $5 billion in each of the past three years. And with $12.8 billion in free cash flow in 2018, the company can afford to be acquiring companies and looking for ways to add growth.

AbbVie trades at a forward P/E of nine although its PEG ratio is a bit high, coming in around 2.7. However, if the integration of Allergan goes smoothly, those numbers can improve very quickly. And with AbbVie also paying its shareholders a dividend of 5.5% annually, there's at least some incentive to hold on to the stock besides share growth.

Good healthcare stocks to build your portfolio around

These stocks have struggled in recent years, with AbbVie falling 26% in two years and Biogen falling 17%, while the Health Care Select Sector SPDR Fund has risen 20% over the same period. But that has made their valuations relatively low and it could be an opportune time to buy for the long-term.

The companies are generating strong profits and they continue to have good free cash flow. Given their growth opportunities, these healthcare stocks could be underrated buys for bargain hunters willing to hang onto shares for years to come.