Not all protein is created equal. Some forms of protein, such as whey, are better than others. Whey protein contains an incredible range of essential amino acids, which are absorbed quickly (1).
Numerous studies show that it can help you increase strength, gain muscle and lose significant amounts of body fat (2Trusted Source). However, whey is more than just protein. It contains many other nutrients, some with potent biological effects.
In fact, it’s one of the best-studied supplements in the world.
This is a detailed article about whey protein — what it is, how it works, and how it can help you achieve your fitness and health goals.
What Is Whey Protein?
Whey protein is a mixture of proteins isolated from whey, which is the liquid part of milk that separates during cheese production.
Whey is found in the watery portion of milk. When cheese is produced, the fatty parts of the milk coagulate and the whey is separated from it as a byproduct (3).
If you've ever opened a yogurt container to see liquid floating on top — that’s whey. Cheesemakers used to discard it before they discovered its commercial value (4).
After being separated during cheese production, whey goes through various processing steps to become what people generally recognize as whey protein — a powder that is added to shakes, meal replacements and protein bars (5).
Whey protein doesn't taste very good on its own, which is why it’s usually flavored. Chocolate-, vanilla- and strawberry-flavored powders are popular.
It's important to read the ingredients list, as some products may have unhealthy additives like refined sugar.
Taking whey protein is a convenient way to add protein on top of your daily intake. This can be important for bodybuilders and gym enthusiasts, as well as people who need to lose weight or are simply lacking protein in their diet.
Most flavored whey proteins are also rather delicious and can be used to add an incredible taste to healthy recipes like smoothies.
Whey is generally well tolerated, though people with lactose intolerance need to be careful, and some people may even be allergic to it (6).
Whey protein is a mixture of proteins in whey, which is a byproduct of cheese production. It’s usually sold as a flavored powder, which is added to shakes, meal replacements, and protein bars.
Whey Protein Supplements Can Help Boost Your Protein and BCAA Intake
Proteins are the main building blocks of the human body.
They're used to make various important things, including tendons, organs, and skin, as well as hormones, enzymes, neurotransmitters, and various molecules.
Proteins are also the building blocks of the contractile elements in your muscles.
They’re assembled from amino acids, smaller molecules that are linked together like beads on a string.
Some amino acids are produced by your body's cells, while others are supplied by the food you eat. The ones that you must get from foods are termed essential amino acids.
Proteins that supply all nine essential amino acids are the best, and whey protein is loaded with them.
It’s particularly high in important branched-chain amino acids (BCAAs) like leucine, and also contains a high amount of cysteine (7Trusted Source).
* Whey protein appears to be particularly effective at stimulating growth in humans. In fact, human breast milk is 60% whey, compared to 20% in cow's milk (10Trusted Source).
The proteins in whey are of very high quality. They’re loaded with essential amino acids, including leucine and cysteine.
Types of Whey Protein: Concentrate vs Isolate vs Hydrolysate
There are several popular types of whey protein.
Their main difference is in the way they have been processed.
Concentrate: About 70–80% protein; contains some lactose (milk sugar) and fat and has the best flavor.
Isolate: 90% protein, or higher; contains less lactose and fat and lacks a lot of the beneficial nutrients found in whey protein concentrate.
Hydrolysate: Also known as hydrolyzed whey, this type has been pre-digested so that it gets absorbed faster. It causes a 28–43% greater spike in insulin levels than isolate (11Trusted Source).
Whey protein concentrate seems to be the overall best option. Many options are available online.
It’s the cheapest and retains most of the beneficial nutrients found naturally in whey. Many people also prefer the taste, which is probably due to the lactose and fat.
If you have problems tolerating concentrate, or you're trying to emphasize protein while keeping carbs and fat low, whey protein isolate — or even hydrolysate — may be a better option.
Keep in mind that even though concentrate is the most popular form, most studies have examined whey protein isolate.
The main types of whey protein are concentrate, isolate, and hydrolysate. They can vary in protein content, taste, digestibility, and price.
Effects of Whey Supplementation on Muscle Mass and Strength
The best-known use of whey protein supplements is for the purpose of increasing muscle mass and strength.
Whey protein is popular among athletes, bodybuilders, fitness models, as well as people looking to improve their performance in the gym.
The ways by which whey protein promotes muscle/strength gain include:
Building blocks: It provides protein and amino acids, which serve as building blocks for increased muscle growth.
Hormones: It increases the release of anabolic hormones that can stimulate muscle growth, such as insulin (12Trusted Source).
Fast absorption: Whey protein is absorbed and utilized very quickly compared to other types of protein (15Trusted Source).
Whey protein has been shown to be particularly effective at increasing muscle growth when consumed right before, after, or during a workout. Muscle protein synthesis is usually maximized in the time period after training (16Trusted Source, 17Trusted Source, 18Trusted Source, 19Trusted Source).
However, a recent review of the evidence concluded that total daily protein intake is the most relevant factor in muscle growth. Whether protein is consumed around the workout or not doesn't seem to matter much (20Trusted Source).
When compared to casein, the evidence is more mixed. Whey appears to be effective in the short-term, but casein stimulates muscle growth over a longer period, making the net effect similar (23Trusted Source, 24Trusted Source, 25Trusted Source, 26Trusted Source, 27Trusted Source).
Also, keep in mind that unless your diet is already lacking in protein, supplementing with whey protein is unlikely to have a significant effect on your results.
In a 12-week study in older adults with adequate protein intake, who did resistance training, there was no difference in muscle growth when supplementing with whey protein or carbohydrates (28Trusted Source).
Therefore, the evidence of whey protein on muscle and strength is mixed, and the results may vary greatly between individuals.
There is a lot of evidence that whey protein is effective at increasing muscle and strength gains, though some studies find no effect.
Whey Protein Improves Satiety and May Promote Weight Loss
It’s well known that protein can aid weight loss, as it’s by far the most satiating macronutrient (29Trusted Source).
Protein can boost energy expenditure by 80–100 calories per day, and make people automatically eat up to 441 fewer calories per day (30Trusted Source, 31Trusted Source, 32Trusted Source, 33Trusted Source).