Nutrition supplement maker Glanbia hiked its full-year profit forecast on Thursday following bumper demand for its protein products, including from customers using them in tandem with weight-loss drugs.

Glanbia now sees higher-than-expected revenue growth across all three of its nutrition divisions, led by its main Optimum Nutrition brand, where first-half sales rose 25 per cent even as it hiked the price of products twice since November.

Protein powders and shakes, traditionally popular with gym goers, have become more visible on supermarket shelves and are among the products consumed by GLP-1 weight-loss drug users advised to add to their protein intake.

"It's difficult to correlate exactly but certainly the increase in demand for protein in whatever format has been driven in some way by the significant increase in GLP-1 usage," Glanbia finance chief Mark Garvey said.

The additional demand has exacerbated a rise in the cost of whey — a key ingredient in protein products — by gobbling up any new supply. Glanbia expects a double-digit percentage rise in whey costs for the rest of 2026 and into 2027, Garvey said.

Optimum Nutrition consumers will face another price hike this quarter, which Glanbia expects to temper demand growth slightly in the second half.

The Irish company expects adjusted earnings per share growth of 17 per cent to 20 per cent at constant currencies this year. It had guided in late April that it would hit the upper end of a 7 per cent to 11 per cent range.

Shares in the Irish company, which have almost doubled in price in the last year, were 6.1 per cent higher in morning trading. - Reuters