What happened

GNC Holdings (NYSE:GNC) stock climbed 17.9% in January, according to data provided by S&P Global Market Intelligence. The share price of the supplements retailer spiked following the release of preliminary fourth-quarter sales results indicating better-than-anticipated performance.

So what

GNC published a sales report on Jan. 18 that indicated its same-store sales for the December-ended quarter would increase 5.7% year over year. The report also guided for earnings between $0.24 and $0.25, up from $0.07 in the prior-year period -- prompting shares to gain roughly 52% in the day's trading.

The beaten-down retailer's share price has struggled amid increased online competition and fears of a potential bankruptcy, but the recent sales data and efforts to build its business overseas have created pricing momentum. The chart below shows GNC's stock performance over the last year:

Stock chart showing GNC Holdings losing roughly 40% of its value over the last year

GNC data by YCharts.

Now what

GNC published fourth-quarter earnings on Feb. 13, delivering on the 5.7% same-store sales growth it had outlined in its preliminary report, and recording $0.25 in adjusted earnings per share. After recent pricing upswings, the company is valued at just 4 times forward earnings estimates and 0.18 times forward sales. Those are metrics that might pique the interest of value-focused investors, but a challenging retail climate for brick-and-mortar outlets and pressure from Amazon and other online-based competitors paint a dim picture for the business's long-term outlook.

To its credit, GNC seems to recognize these threats and isn't standing still. The company recently announced a deal with Harbin Pharmaceutical that will further the manufacturing and sale of GNC products in China. The deal also includes a $300 million investment from Harbin that makes the Chinese company the largest shareholder in GNC.