Protein quality ratings

The information below shows four different rating methods scientists use to evaluate the quality of several proteins. The higher the number, the better your body uses the protein.

Protein Differences


Whey Protein

This protein from milk is a by-product of cheese making. About 20% of the protein in milk is whey and 80% is casein.


1. Whey is the highest quality protein, better than all other animal proteins.
2. Digests fast; won't leave you feeling full.
3. Supports immune health from certain protein components.
4. High in BCAAs (branched chain amino acids), important for bodybuilders and dieters since BCAAs can be used for fuel, potentially sparing muscle tissue.
5. Good for lactose-sensitive people.


1. Because it digests fast, it won't keep you satisfied for very long.
2. Lower in naturally occurring glutamine than milk (casein) proteins, which is why glutamine is added to some formulas.


Milk Protein (Casein)

Casein is the predominant protein in milk. For example, the protein in cheese and cottage cheese is casein. Sometimes called calcium-, sodium- or potassium-caseinate.


1. This 'slow' digesting protein keeps you full longer since it must form a gel during digestion before it is absorbed. This slower transit time may extend the exposure of the protein in the intestines and may help increase absorption.
2. Has a naturally high glutamine content, higher than whey, soy or egg.
3. Along with whey, casein is one of the best proteins for building muscle.
4. Very low in lactose.


1. Some people have allergies to casein protein. If you have milk allergies from lactose only, then casein should not pose any problems.


Egg Protein (egg white or egg albumen)

This protein used to be the 'gold standard' that all other proteins were measured against, until whey protein came along. Most formulas contain very little egg protein.


1. Excellent amino acid profile with sulfur-bearing amino acids.


1. Slightly bitter taste.
2. People unjustifiably perceive it to be high in cholesterol. But the bad rap on egg comes from the yolk, not the egg white. Protein powders use egg white.


Soy Protein

Soy protein is processed from the soybean plant. Most of the fat, fiber and carbs are removed. Since it is a vegetable product, it has no cholesterol.


1. Reduces heart disease risk.
2. May help with normal thyroid function to keep your metabolism steady.
3. High in glutamine, about the same as casein.


1. Not as high quality of a protein due to limiting essential amino acids.
2. Not as good as whey or milk proteins for building muscle.
3. Does not taste very good compared to whey or casein.


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