Water or milk in a protein shake? Start with what the drink needs to contribute. The mixer changes the total, so compare the finished shake rather than treating one liquid as the universal best choice. Use the actual powder serving and the amount of liquid you pour. Milk alternatives vary too. The word almond, oat or soy does not tell you the complete drink's protein or calorie content. In this fictional example, the powder supplies twenty-four grams of protein and one hundred and twenty calories. The example milk adds eight grams and one hundred and twenty-five calories. The finished drink has thirty-two grams and two hundred and forty-five calories. Water may suit a simple protein addition. Milk may help make a more substantial snack. Neither calculation tells you that a shake is a complete meal or that everyone needs the same amount. Changing the mixer does not remove ingredients already in the powder. Water cannot make whey milk-protein-free. Read both allergen labels and follow any individual advice relevant to your health. Taste, price and storage matter because the routine has to work in real life. The article includes a simple calculation and a comparison note you can use for whichever products you actually buy.