The liquid left after cheese or paneer
Whey protein is the protein in the liquid left when milk is set for cheese or paneer. The solid curd keeps most of the casein. Lactose, a little fat, and minerals stay in the liquid. When that liquid is dried, what is left is a powder.
The types of whey protein are concentrate, isolate and hydrolysate
Three names show up on the tubs. They tell you how far the filtering went. With concentrate, liquid whey is filtered and dried, and more of the original milk stays in the powder. A concentrate label often prints about 70 to 80% protein by weight. Isolate is filtered again, so the label shows a higher percentage, often about 90%. Hydrolysate starts from either of those, once enzymes have cut the protein into smaller pieces, and it can taste bitter.
A higher percentage means more protein in the same scoop. The name on the front tells you if the powder is concentrate, isolate, or hydrolysate. You should count the protein grams printed next to the serving.
| Name on the pack | What was done to the liquid | Protein share often printed |
|---|---|---|
| Concentrate (WPC) | Filtered and dried, with more of the original liquid kept | Often about 70 to 80% |
| Isolate (WPI) | Filtered further | Often about 90% |
| Hydrolysate (WPH) | Enzymes have cut the protein into smaller pieces | Follows the powder it was made from |
Protein is used all through the body
Harvard's Nutrition Source says protein is found throughout the body, in muscle, bone, skin, hair, and almost every other tissue. It makes up the enzymes that power many chemical reactions, and the haemoglobin that carries oxygen in the blood. Nine amino acids have to come from food, because the body does not make them. Dairy foods are among the foods that page lists as sources of complete protein, with the amino acids used to make new protein.3 Whey comes from milk, so a whey serving is one way to put those grams toward the protein for the day.
Protein in one serving
A tub may say protein powder, or whey, or just give a scoop size. You still stir a set amount into cold water or milk, and you read the protein next to the serving size. A number per 100 g is for the powder itself. The serving is the amount you stir into the glass.
Horlicks Protein names what is in the pouch. Chocolate and Coffee are fermented yeast protein. Unflavoured is fermented yeast protein and whey protein concentrate. The Unflavoured sachet weighs 36 g and already lists 24 g of protein, so you do not calculate 70 to 80% of 36 g. Mix that sachet with 200 ml of cold water or milk.
How one serving fits the day's protein
If you weigh 65 kg, ICMR-NIN's Dietary Guidelines for Indians, 2024, put your day at about 54 g of protein. The guideline is 0.83 g for each kilogram.1 The British figure for that same weight is about 49 g, from 0.75 g per kilogram.
A Horlicks Protein milkshake lists 20 g of ultra-filtered milk protein in 240 ml. Those 20 g are part of the 54 g, so other meals still have 34 g to cover. If a powder label gives protein per 100 g, multiply by the weight of what you use and divide by 100. Say the powder is 80 g of protein per 100 g and the serving is 30 g. Multiply 80 by 30, then divide by 100. That is 24 g of protein in the glass.
You do not have to get all 54 g from one glass. If you use half a serving, count half the protein printed for the full serving.
A 36 g sachet that lists 24 g of protein puts 24 g into the day's 54 g, for a 65 kg adult. Half the sachet is about 12 g of protein, so meals still have about 42 g to cover. Two full sachets list 48 g of protein and 72 g of powder, which leaves about 6 g of the 54 g. The percentage on the label tells you how much of the powder is protein. If the label says 80 g of protein per 100 g, a 25 g scoop works out to 20 g of protein.
To summarise, people take whey because protein is used throughout the body, in muscle, bone, skin, hair and other tissue, and because nine amino acids have to come from food. The three names are three depths of filtering, not three different foods. Concentrate keeps more of the milk in the powder, and a typical label there is about 70 to 80% protein. Take the filtering further and you are looking at isolate, where the label is often about 90%. Hydrolysate is either of those after enzymes have cut the protein smaller, and it can taste bitter. What you add to the day is the protein in one serving. For a 65 kg adult that day is about 54 g. A Horlicks Protein Unflavoured sachet puts 24 g of that into the day, from the 36 g you stir into 200 ml of cold water or milk.
Sources
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ICMR-National Institute of Nutrition. Dietary Guidelines for Indians, 2024.
View ICMR-National Institute of Nutrition. -
British Nutrition Foundation. Nutrition requirements, Reference Nutrient Intake for protein, from the 1991 UK Dietary Reference Values.
View British Nutrition Foundation. -
Harvard T.H. Chan School of Public Health. The Nutrition Source, Protein.
View Harvard T.H. Chan School of Public Health.