As 2013 begins, now's a good time to look at the future prospects for the stocks you own. If you don't know where a company's headed in the next year and beyond, then it's impossible to make an informed decision about whether you should add the stock to your portfolio -- or sell it if you already own it.

Today, I'll look at Herbalife (NYSE:HLF). The seller of nutritional supplements and weight-management products had put up lackluster numbers through mid-December, but in the past three weeks, the bottom has fallen out of the stock. Below, you'll learn more about Herbalife's prospects for 2013.

Stats on Herbalife

Average Stock Target Price

$75.43

Full-Year 2012 EPS Estimate

$4.03

Full-Year 2013 EPS Estimate

$4.56

Full-Year 2012 Sales Growth Estimate

17.4%

Full-Year 2013 Sales Growth Estimate

11%

Forward P/E

7.1

Source: Yahoo! Finance.

Will Herbalife heal itself in 2013?
Analysts have huge hopes for Herbalife, with a target price that's fully 130% above where the shares currently trade. With solid earnings and revenue growth projected for 2013, the stock's forward P/E of just 7 seems ridiculously cheap.

But in the past few weeks, the fight over Herbalife's legitimacy has gotten red-hot. Short-seller Bill Ackman of Pershing Square Capital Management gave a presentation explaining the rationale of his massive short position, alleging that the company is a pyramid scheme and has zero value for shareholders. Herbalife has promised to answer Ackman's accusations in a presentation scheduled for next Monday, but the market wasn't willing to wait and sent the stock plunging more than 35% in just three days.

Fundamentally, the stock seems poised to capitalize on a popular trend. With obesity drugs from Arena Pharmaceuticals (NASDAQ:ARNA) and VIVUS (NASDAQ:VVUS) getting a lot of attention but not yet creating sales, those looking for weight-loss alternatives have had to go either with nutritional solutions like Herbalife or custom-food programs Weight Watchers (NYSE:WTW) or NutriSystem (NASDAQ:NTRI). Without inquiries from Ackman and David Einhorn casting those figures into doubt, Herbalife would look like a huge value.

Looking forward, a lot will depend on how the company comes off on its analyst day next Monday. Without a strong performance, more selling pressure could send shares even lower.

Click here to add Herbalife to My Watchlist, which can find all of our Foolish analysis on it and all your other stocks.

Fool contributor Dan Caplinger has no positions in the stocks mentioned above. You can follow him on Twitter @DanCaplinger. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.