How should I measure protein powder?
Use the label serving as a starting point, but weigh the powder if precision matters. Scoops are convenient, not exact measuring devices. Different powders have different densities, powders settle in the tub, and a "scoop" can vary depending on whether it is loose, packed, rounded, or leveled.
Track protein powder by grams of powder, not by scoop volume or by how full the shaker looks. If the label says one serving is 34 grams, put the shaker on the scale, tare it to zero, add 34 grams of powder, and log that serving. If your scoop happens to hold 29 grams one day and 41 grams another day, weighing removes the guesswork.
Also log the full product, not just the protein grams. Whey, casein, plant protein powders, meal replacements, and ready-to-drink shakes can include meaningful carbohydrates, dietary fat, fiber, sugar alcohols, or added ingredients. Those calories still count toward calorie balance.
If you use protein powder occasionally, scoop-based tracking is probably close enough. If you use it daily, are dieting aggressively, or are troubleshooting stalled progress, weigh it. The small errors are not dramatic once, but they can become a pattern.