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 ().

Numerous studies show that it can help you increase strength, gain muscle and lose significant amounts of body fat ().

However... whey is more than just protein. There are tons of other nutrients in there, some with potent biological effects.

Whey protein has also been shown to have benefits for depression, blood pressure, blood sugar and even helping to treat symptoms of HIV and cancer ().

In fact, it is 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.

Whey protein is a mixture of proteins isolated from whey. Whey is the liquid part of milk that separates during cheese production.

Milk actually contains two main types of protein: casein (80%) and whey (20%).

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 by-product ().

If you've ever opened a yogurt container to see liquid floating on top, this is whey. Cheese makers used to discard it before they discovered its commercial value ().

After being separated during cheese production, whey goes through a series of processing steps to become what people generally recognize as whey protein... a powder that is added to shakes, meal replacements and protein bars ().

Whey protein doesn't taste very good on its own, which is why it is usually flavoured. Chocolate, vanilla and strawberry flavored powders are popular.

It's important that you read the ingredients list, because some of them can have unhealthy additives like refined sugar.

Taking whey protein is a convenient way to add 25-50 grams of 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 pretty delicious and can be used to make healthy recipes (like smoothies) taste incredibly good.

Whey is generally well tolerated, although people with lactose intolerance need to with it. There are also some people who are allergic to whey ().

Bottom Line: Whey protein is a mixture of proteins in whey, which forms as a by-product of cheese production. It is usually sold as a flavoured powder, which is added to shakes, meal replacements and protein bars.

Proteins are the main building blocks of the human body.

They're used to make various important things, both large and small.

This includes tendons, organs and skin... as well as hormones, enzymes, neurotransmitters and all sorts of tiny molecules.

Proteins are also the building blocks of the contractile elements in muscle.

Proteins are assembled from amino acids, smaller molecules that are linked together like beads on a string.

Some amino acids are produced by the body's cells, while others must be gotten from foods. The ones that we must get from foods are termed "essential" amino acids.

Proteins that supply all the essential amino acids are the best... and whey protein is loaded with them.

It is particularly high in important Branched Chain Amino Acids (BCAAs) like Leucine, and also contains a large amount of Cysteine ().

Studies show that Leucine is the most anabolic (growth promoting) amino acid, and Cysteine can help boost levels of the cellular antioxidant Glutathione (, ).

Whey protein appears to be particularly effective at stimulating growth in humans. Human breast milk is actually 60% whey, compared to 20% in cow's milk ().

Bottom Line: The proteins in whey are of a very high quality. They are loaded with essential amino acids, including Leucine and Cysteine.

There are several popular types of whey protein available.

The main difference between them, is 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 is missing 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 ().

Whey protein concentrate seems to be the overall best option... it is the cheapest and retains most of the beneficial nutrients found naturally in whey. Many people also prefer the taste, which is probably because of the small amounts of lactose and fat.

If you have problems tolerating concentrate, or you're trying to emphasize protein while keeping carbs and fat low, then whey protein isolate (or even hydrolysate) may be a better option.

Keep in mind that despite concentrate being the most popular form, most of the studies used whey protein isolate.

Bottom Line: The main types of whey protein are concentrate, isolate and hydrolysate. They can vary in protein content, taste, digestibility and price.

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 main effects of whey on muscle/strength are:

  1. Building blocks: It provides protein and amino acids, which serve as building blocks for increased muscle growth.
  2. Hormones: It increases release of anabolic hormones that can stimulate muscle growth, such as Insulin ().
  3. Leucine: It is high in the amino acid Leucine, which is known to stimulate muscle protein synthesis at the molecular and genetic level (, ).
  4. Fast absorption: Whey protein is absorbed and utilized very quickly compared to other types of protein ().

Whey protein has been shown to be particularly effective at increasing muscle growth when consumed right before, after or during a workout, but muscle protein synthesis is usually maximized in the time period after training (, , , ).

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 ().

When compared to other types of protein, such as soy protein, whey protein has usually performed slightly better (, ).

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, so the net effect appears to be similar (, , , , ).

However... keep in mind that unless your diet is already lacking in protein, supplementing with whey protein is unlikely to have a huge effect on your results.

In a study of elderly individuals who were already eating adequate protein, there was no difference in muscle growth between whey and carbohydrate, during 12 weeks of resistance training ().

Therefore, the evidence of whey protein on muscle and strength is mixed, and the results may vary greatly between individuals.

If you're already eating plenty of meat, fish, eggs and dairy (also high in quality protein), then the benefits of adding whey will probably be minimal.

Bottom Line: There is a lot of evidence that whey protein is effective at increasing muscle and strength gains, although some studies find no effect.

It is well known that protein can help with weight loss.

It is the most fulfilling macronutrient, by far ().

Protein can boost metabolism by 80 to 100 calories per day, and make people automatically eat up to 441 fewer calories per day (, , , ).

In one study, eating protein at 25% of calories cut cravings by 60%, and reduced the desire for late-time snacking by half ().

Taking whey protein is a great way to increase your protein intake, which should have major benefits for weight loss.

Studies have shown that replacing other sources of calories with whey protein, combined with weight lifting, can cause weight loss of about 8 pounds, while increasing lean muscle mass ().

Therefore... if you're trying to lose weight, then a whey protein supplement can help you both lose weight and hold on to your precious muscle (, ).

Bottom Line: Protein has been shown to help weight loss by boosting metabolism (calories out) and reducing appetite (calories in). Whey protein can help increase fat loss, while preserving lean muscle mass.

Whey is more than just a high quality protein source, it also contains other beneficial nutrients.

This includes lactoferrin, beta-lactoglobulin, alpha-lactalbumin and immunoglobulins ().

Beyond just muscle, strength and leanness, whey protein can provide numerous other health benefits.

This includes lowering blood pressure, blood sugar and reducing symptoms of stress and depression (, , , ).

It has also been shown to help protect against cancer, reduce symptoms of hepatitis, increase bone mineral density, improve immune function in HIV patients and increase lifespan in mice (, , , , , , , , , , ).

The fact that whey protein is very high in the amino acid Cysteine seems to mediate many of the health benefits. Cysteine does this by raising levels of Glutathione, the main antioxidant substance in the body's cells (, ).

Here is a list of even more health benefits: 10 Evidence-Based Health Benefits of Whey Protein.

Bottom Line: Whey has many beneficial components besides just protein. It is high in the amino acid Cysteine, which raises levels of the antioxidant Glutathione and leads to all sorts of benefits.

A commonly recommended dosage is 1-2 scoops (around 25-50 grams) per day, usually after workouts.

It is recommended that you follow the serving instructions on the packaging.

Keep in mind that if your protein intake is already high, adding whey protein on top of your current intake may be completely unnecessary.

Despite concerns about protein causing kidney damage and contributing to osteoporosis, this is not true.

In fact, protein has been shown to protect against osteoporosis, while having no impact on healthy kidneys (, , , ).

However, people with current kidney or liver issues may want to avoid whey protein, or at least consult with a medical professional before taking it.

Eating too much whey protein can cause digestive issues such as nausea, flatulence, diarrhea, pain and cramping. Some people are also allergic to whey.

If you can't tolerate regular whey protein concentrate, then isolate or hydrolysate may be more appropriate... or simply avoiding whey protein and eating other protein rich foods instead.

But generally speaking, whey protein has an excellent safety profile and most people can consume it without any problems whatsoever.

At the end of the day, whey protein is an exceptionally healthy way to add more protein to your diet. It is a quality protein source that is absorbed and utilized efficiently by the human body.

This is particularly important for athletes, bodybuilders, or people who need to gain muscle mass and strength, while losing fat.

When it comes to muscle gain and fat loss, protein is the king of nutrients... and whey protein seems to be even better than other forms of quality protein.

For more details on the benefits of protein and how much of it you should be eating, read this: Protein Intake - How Much Protein Should You Eat Per Day?