Oct 21 (Reuters) - Philip Morris International PM.N raised its annual profit forecast for the third time this year on Tuesday, benefiting from strong demand for its portfolio of smoking alternatives.

PMI has been counting on newer products, such as its nicotine pouch brand Zyn, the leading label in the U.S., to offset long-term declines in its cigarette brands Marlboro, Chesterfield and others in some markets.

"Our global smoke-free portfolio is outgrowing the industry by a clear margin, driving positive total volumes, strong top-line growth and impressive margin expansion," CEO Jacek Olczak said.

Shares of the company were up 4% in premarket trading.

With ever-stricter regulation and health concerns pushing consumers away from tobacco, cigarette makers have been heavily investing in developing products such as pouches and vapes to replace lost revenues and profits.

The company expects an adjusted annual profit of $7.46 to $7.56 per share, compared with its prior forecast of $7.43 to $7.56.