It has become a lifeline for the dairy industry at a time when more traditional dairy products are facing oversupply, leading to milk price cuts for farmers.

Sports nutrition is driving an estimated 45% of the global increase in demand for high-protein powders. Whey and casein milk ingredients are estimated to account for 55% of the market.

Protein powder, typically flavoured, is a concentrated source of protein that helps people meet their daily protein requirements without preparing a full meal. Protein is the nutrient the body uses to build and repair muscles, skin, and other tissues, as well as to produce hormones and enzymes that keep the body functioning properly. Gym-goers commonly use protein powder after training to support muscle repair and growth.

Protein powders can also benefit older adults and people who struggle to get enough protein from food alone. Those recovering from surgery, illness, or burns, as well as people experiencing a loss of appetite, often require additional protein.

Older adults frequently do not consume enough protein and can experience muscle loss as a result. The rise of weight-loss injections has fuelled a further surge in demand for dairy proteins. This includes users of GLP-1 weight-management treatments, for whom adequate protein intake is essential to maintain muscle mass and support recovery when treatment suppresses appetite and slows digestion. High-quality whey proteins, such as whey protein isolate and hydrolysed whey protein, are commonly recommended for this purpose.

Whey was once a by-product of cheese production and was largely used as pig feed. It is now a key ingredient in food products aimed at consumers seeking to prevent muscle loss.

The protein boom has prompted milk processors around the world to invest heavily in advanced whey-processing facilities.

It has also increased demand for dairy products such as high-protein yoghurts, cheeses, and beverages.

In Ireland, Glanbia and Tirlán are among the companies investing to expand high-protein production. Both were already well-established whey protein producers and are among those benefiting from demand for premium-quality whey produced in countries with strict dairy regulations and grass-fed, pasture-raised cows, including Ireland, New Zealand, the United States, and Germany.

Optimum Nutrition, a subsidiary of Irish-based Glanbia, claims its Gold Standard Whey product is the world’s best-selling whey protein. It retails for approximately €44 for a 900g pack.

Optimum Nutrition is one of the longest-established sports nutrition companies, having launched its first products in 1986. It was acquired by Glanbia plc in 2008 and now operates within the Glanbia Performance Nutrition division.

Its success in meeting growing demand for performance nutrition is regarded as a major factor behind Glanbia’s share price reaching record highs.

Farmer-owned co-operative Tirlán was part of Glanbia until it acquired the remaining 40% stake in its Irish dairy and grain business from Glanbia plc in 2022.

Ireland’s largest dairy processor, handling around one-third of the national milk pool, Tirlán is Europe’s largest cheddar cheese producer and the second-largest whey protein isolate manufacturer in the EU.

Last November, Tirlán announced a €126m investment in a new whey-processing facility at its Ballyragget site in Co Kilkenny. The facility is expected to become operational by mid-2027.

Carbery Group in West Cork is also highly regarded as a producer of premium whey protein for the sports nutrition and infant nutrition markets.

According to Carbery, the global sports nutrition market is growing by 10% annually, with almost 80% of that growth generated by protein-based products. The company says the market is evolving from sports nutrition towards active nutrition, targeting a broader audience of health-conscious consumers seeking energy, recovery, and everyday wellness.

Dairygold operates one of Europe’s largest casein production plants, commissioned in Mitchelstown in 2025, and is investing in diversifying its whey production to meet growing global demand for high-protein products.

Meanwhile, Kerry Dairy Ireland, now operating as Kinisla, has reported sales growth of more than 20% for its milk proteins in 2025.

Lakeland Dairies develops milk proteins tailored to consumers’ varying functional and nutritional needs, including protein-rich diets.

The commissioning of Arrabawn’s new plant this year will enable the production of spray-dried caseinate, a product widely used in dietary protein supplements.