GNC's results were slightly better than Wall Street expected, and the company made modest increases to its full-year guidance.
The company said its net income rose to $62.2 million, or 60 cents per share, from $48.7 million, or 45 cents per share. Its adjusted earnings came to 61 cents per share. Analysts surveyed by FactSet expected 58 cents per share.
Revenue increased to $621.6 million from $538 million. Analysts expected $618.6 million in revenue.
GNC said its revenue from company-owned stores in the U.S. and Canada rose 16 percent to $445 million as it opened 155 new stores over the last year, got more revenue from GNC.com and acquired LuckyVitamin.com. The company said sales at locations open at least a year grew 9.8 percent, down from 10.3 percent a year ago.
Revenue from locations open at least a year is considered an important measurement of retailer health because it leaves out results from stores that have opened or closed in the last year.
GNC said revenue from franchised stores rose 20 percent to $108.8 million, and its manufacturing and wholesale revenue rose to $67.8 million from $61.8 million.
William Blair & Co. analyst Mark Miller said the company's third-quarter results and fourth-quarter outlook were
Miller kept an "Outperform" rating on the stock.
GNC now expects to report adjusted net income of $2.29 per share on $2.45 billion in revenue in 2012, up from its previous estimates of $2.21 per share in net income and $2.43 billion in revenue.
Analysts expect earnings of $2.26 per share on revenue of $2.43 billion.
Despite the improved performance, GNC shares fell as much as 13.4 percent on Thursday. They recovered most of those losses and were down 80 cents, or 2.1 percent, to $37.87 in afternoon trading. The stock has traded between $23.85 and an all-time high of $42.70 in the last 12 months.