Adam Meyer

Author: Expert reviewer:

March 10, 2023

Adam Meyer

Certified holistic nutritionist

By Adam Meyer

Certified holistic nutritionist

Adam Meyer is a health writer, certified holistic nutritionist, and plant-based athlete

Lauren Torrisi-Gorra, M.S., RD

Expert review by

Lauren Torrisi-Gorra, M.S., RD

Registered Dietitian

Lauren Torrisi-Gorra is a Registered Dietitian with a Grand Diplôme in Culinary Arts from the French Culinary Institute and a bachelor’s in Communication and Media Studies from Fordham University. After a decade working in the culinary and media worlds, Lauren pursued her ultimate passion and received her master’s degree in Clinical Nutrition and Dietetics at New York University.

Plastic spoon in protein powder

Image by vovashevchuk / iStock

March 10, 2023

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Whey is one of two types of protein found in milk (along with casein) and it’s among the most well-researched dietary supplements. When used correctly, it can be helpful for building lean muscle mass, promoting recovery, and more. Here’s what to know about the main benefits of whey protein, how it compares to other protein sources, the best whey protein for beginners, tips for timing your whey intake, and more.


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Types of whey protein

Whey is the clear liquid portion of milk left over from the cheese or yogurt manufacturing process after coagulation and curd removal.

The milk undergoes quality testing before enzymes are added to separate the curd (casein) from the liquid whey. Then, the liquid whey is pasteurized before being processed into its concentrate and isolate forms.

Whey is a high-quality complete protein (meaning it contains all nine essential amino acids1) and it makes up 20% of the protein2 found in dairy milk.

There are three main types of whey protein: concentrate (WPC), isolate (WPI), and hydrolysate (WPH). WPC contains 70-80% protein and is the least processed form3, retaining some lactose and fat content and other nutritional value. WPI is a more processed form of whey, comprising 90-95% protein and less than 1% lactose4, making it a safer option for people with lactose intolerance.

WPH is free from fats, carbs, and lactose and contains the highest protein content. In addition, WPC has been shown to enhance fat mass reduction more than other forms of whey protein, according to a 2019 meta-analysis published in Nutrients5. However, it’s the most processed form with the least nutritional value.


Whey is the clear liquid portion of milk and there are three main types of it: concentrate, isolate, and hydrolysate. Regardless of the form, whey protein is easy to digest, readily absorbable, and effective for building lean muscle mass.


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Whey protein benefits


It’s a source of high-quality protein.

Whey protein contains sufficient amounts of all nine essential amino acids (the building blocks of protein6), making it an excellent high-quality protein option.

Whey protein also has an excellent nutritional profile.7 It contains several vital vitamins and minerals for optimal health, including B vitamins, calcium, potassium, iron, magnesium, zinc, selenium, phosphorus, and choline.


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It may improve your body composition.

If your fitness goal is to improve your body composition (your proportion of lean body mass and body fat mass8), whey protein can help you get there.

According to one study9, the best results have been found when whey protein intake is combined with resistance training and reduced calorie intake.

Other research10 has found that whey protein can improve body composition and reduce risk factors for cardiovascular disease in overweight and obese people. But, again, to get the most body composition benefits out of your whey protein, pairing it with resistance training and eating at a slight calorie deficit is ideal.


It may help you gain muscle.

Taking whey protein can ramp up protein metabolism and exercise recovery, per one study11. Whey protein enhances “whole body anabolism” (e.g., muscle-building) to help support recovery and muscle protein synthesis after strenuous exercise like resistance training.

Additionally, whey protein is an excellent source of the branched-chain amino acids (BCAAs) leucine, isoleucine, and valine, which are well-research and praised for their benefits regarding muscle protein synthesis12 and post-exercise recovery13.

“Whey is often considered the gold standard for its ability to maximally stimulate protein synthesis for the least amount of protein. This is because it is well absorbed and has a very high leucine content,” Eric Williamson, Ph.D., R.D., a registered dietitian, exercise nutrition expert, and founder of Unlocked Fitness and Nutrition, tells mindbodygreen.

Leucine is important because it triggers muscle protein synthesis. This has made whey protein the most popular supplement form of protein for building muscle mass and other adaptations to exercise,” Williamson adds.


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It may help you lose fat.

Satiety is the feeling of fullness and satisfaction you experience after a meal. It helps to suppress hunger and cravings to help reduce caloric intake and prevent overeating. And among the three macronutrients (carbs, fats, protein), protein is well known as being the most satiating16.

When it comes to the best proteins for satiety, whey is king. Research17 shows that whey protein supplementation positively affects satiety and fullness compared to other types of protein (e.g., casein) and carbohydrate supplementation.


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It may lower blood pressure.

High blood pressure (also called hypertension) can jeopardize cardiovascular health by increasing risk of stroke, heart attack, chronic kidney disease, and vascular dementia.

One study18 found whey protein significantly decreased systolic blood pressure in overweight and obese adults with mild hypertension by improving endothelial function (opening and closing of the arteries).

Additionally, whey protein can help lower “bad” LDL cholesterol19, a significant risk factor for high blood pressure.


It may help to treat type 2 diabetes.

Research shows whey protein may be an effective supplement for helping to treat type 2 diabetes. Type 2 diabetes is a chronic condition characterized by high blood sugar levels and impaired function of the hormone insulin that allows cells to absorb blood sugar.

Whey protein can improve blood sugar control19 and reduce insulin resistance20 in people with type 2 diabetes.

One study21 found that people with type 2 diabetes who consumed a whey protein supplement alongside a high-carb, high-fat meal had improved blood sugar control and insulin response.


It may strengthen your immune system.

How it compares to plant protein

Whey has a more complete amino acid profile than plant (or vegan) protein sources like soy, pea, and brown rice. However, research24 shows that whey and plant proteins are equally beneficial for body composition25, strength, muscle growth, and recovery.

While plant and vegan proteins can be as effective as whey, you typically need to consume more of them to reap the same benefits, according to one study26. That means you’ll need to eat more to reach your protein needs and potentially cause weight gain.

“Like any animal protein, whey has a more complete amino acid profile than plant proteins like pea and soy. This means it has sufficient amounts of all amino acids to stimulate protein synthesis at a lower dose than pea or soy,” states Williamson.

Who should take it?

Dietary supplements, such as protein powders, should only be used as the name indicates: to supplement an already well-balanced diet.

With that said, supplements like whey protein can be an excellent option for helping to fill in nutritional gaps and meet daily protein needs.

This is especially true if your fitness goal is to build muscle or enhance athletic performance. The American College of Sports Medicine (ACSM) recommends athletes and highly active people consume between 1.2 and 2.0 grams of protein per kilogram (g/kg) of body weight daily—significantly more compared to the current recommendation of 0.8 g/kg of body weight daily27.

“Anyone who has difficulty meeting their protein needs could benefit from consuming a protein supplement like whey,” says Williamson. “Those participating in regular intense exercise and those in a calorie deficit to lose weight may particularly benefit from protein supplementation because their protein requirements are higher.”

How to find a good option

Whether you prefer whey protein concentrate, isolate, or hydrolysate, choosing a high-quality supplement is crucial. “Ensuring your protein supplement has been third-party tested can help ensure the product is pure and does not contain banned substances,” says Williamson. When looking for a high-quality protein powder, choose an unsweetened, sugar-free product with few added ingredients to reap the most health benefits possible.

Timing & best practices

Following these protein best practices can help you get the most out of your whey protein:

Side effects & risk of too much protein

Regularly consuming more than 2.0 grams of protein per kilogram of body weight daily can possibly lead to digestive, kidney, and vascular health issues29.

“Too much protein could lead to inadequate consumption of other important nutrients like fat, fiber, carbohydrates, vitamins, and minerals,” says Williamson. “For example, if you experience constipation, you may be consuming too much protein instead of adequate fiber.”

In addition, high protein intake can negatively impact kidney function30 in those with kidney disease.

Depending on your overall diet, side effects of too much protein can include:

  • Impaired kidney function in people with kidney disease
  • Increased risk of heart disease
  • Elevated LDL (“bad”) cholesterol
  • Bad breath
  • Headaches
  • Constipation
  • Diarrhea

Frequently Asked Questions

Is it good to drink whey protein every day?

Whey protein is safe for daily consumption. However, dietary supplements like protein powders should only be used to supplement an existing healthy diet.

What are the benefits of whey protein for runners?

Runners can benefit from whey protein since it’s a complete protein source containing all nine essential amino acids, including the branched-chain amino acids (BCAAs) vital for muscle growth and recovery. Also, whey protein is easy to digest and readily absorbed in the blood and muscle, making it an excellent option for refueling after a run.

Does whey protein reduce belly fat?

While it won’t target belly fat specifically, you can use whey protein for weight loss and increased fat-burning while retaining lean muscle. “Higher protein intakes can lead to greater satiety, causing you to eat less,” explains Williamson. “Higher protein diets in a calorie deficit help maintain lean mass, meaning more weight loss will come from body fat.”

The takeaway.

Whey protein is a complete protein source that helps to build muscle, promote fat loss, and enhance body composition. Introducing a high-quality whey protein powder into your routine is a great way to work more protein into your diet and experience the health benefits that come with it. Just make sure you’re getting plenty of protein from whole foods, too.