Whey protein is one of the most popular protein products on the market.
It’s a milk-based protein that’s quickly digested and easily absorbed by your body, making it the perfect choice around your workouts.
Whey protein is considered a complete protein, as it contains all nine essential amino acids necessary for optimal health.
It’s particularly high in the amino acid leucine, which turns on processes in your body involved in building muscle (3).
Owing to its high leucine content and quick digestion, whey protein increases muscle protein synthesis — the process by which your muscles grow — more than other types of protein, specifically casein and soy (4).
Several meta-analyses show that whey protein supplements significantly increase muscle size and strength when combined with resistance training (5, 6, 7, 8).
Whey protein also promotes feelings of fullness, which can help you lose fat by eating less throughout the day (8, 9, 10).
Additionally, whey protein spares the loss of lean muscle mass during calorie restriction, especially when combined with exercise (10, 11).
This is important because your body tends to lose lean muscle mass along with body fat when you diet (12, 13).
Dymatize Nutrition makes a great product that packs 25 grams of high-quality whey protein per scoop.
SUMMARYWhey protein digests quickly and is easily absorbed by your body, making it an ideal protein source for your workouts. It also aids fat loss by promoting feelings of fullness and decreasing the loss of lean muscle mass when dieting.
Whey protein is one of the most popular protein products on the market.
It’s a milk-based protein that’s quickly digested and easily absorbed by your body, making it the perfect choice around your workouts.
Whey protein is considered a complete protein, as it contains all nine essential amino acids necessary for optimal health.
It’s particularly high in the amino acid leucine, which turns on processes in your body involved in building muscle (3).
Owing to its high leucine content and quick digestion, whey protein increases muscle protein synthesis — the process by which your muscles grow — more than other types of protein, specifically casein and soy (4).
Several meta-analyses show that whey protein supplements significantly increase muscle size and strength when combined with resistance training (5, 6, 7, 8).
Whey protein also promotes feelings of fullness, which can help you lose fat by eating less throughout the day (8, 9, 10).
Additionally, whey protein spares the loss of lean muscle mass during calorie restriction, especially when combined with exercise (10, 11).
This is important because your body tends to lose lean muscle mass along with body fat when you diet (12, 13).
Dymatize Nutrition makes a great product that packs 25 grams of high-quality whey protein per scoop.
SUMMARYWhey protein digests quickly and is easily absorbed by your body, making it an ideal protein source for your workouts. It also aids fat loss by promoting feelings of fullness and decreasing the loss of lean muscle mass when dieting.
2. Casein Protein
Like whey, casein is a milk-based protein that contains all the essential amino acids your body needs. However, your body digests casein protein much slower than the rapidly digested whey protein.
This is because casein forms curds in your stomach once exposed to stomach acid. These curds are not easily broken apart and take your body much longer to digest and absorb.
But because your body absorbs casein protein at a slower rate, it provides your muscles with a steady supply of amino acids over a longer period — usually between five and seven hours (14).
While casein protein doesn’t increase muscle protein synthesis to the same extent as whey, the continuous supply of amino acids helps prevent muscle breakdown and supports muscle protein synthesis longer (15).
This makes casein protein particularly useful for promoting muscle growth during fasting, for example before sleep or between meals.
Studies in men show that consuming 20–30 grams of casein protein before bed decreases muscle protein breakdown and supports muscle building (16, 17, 18, 19).
And because aging is associated with a loss of muscle mass, older men may especially benefit from the muscle-preserving effects of casein protein (19).
Here is a quality casein powder by Optimum Nutrition that also provides 60% of your daily calcium needs.
SUMMARYCasein is a complete protein that comes from milk. Your body takes much longer to digest and absorb casein than it does whey. This makes casein beneficial for supporting muscle growth during periods of fasting.
3. Whey-Casein Blend
Whey-casein protein blends combine the fast- and slow-digesting properties of whey and casein protein powder.
With a whey-casein blend, you get the best of both worlds: a spike in muscle protein synthesis from the rapidly-absorbed whey and a prolonged decrease in muscle breakdown from the slowly-absorbed casein (20).
In one study, 16 men at rest drank 20 grams of whey protein blend or 20 grams of whey-casein protein blend (21).
The researchers took muscle samples from the men two hours before and several hours after consumption and found no difference between the two groups in muscle protein synthesis, suggesting the blend is just as effective as whey protein when resting.
However, it’s unclear if protein blends are as effective as whey protein for increasing muscle protein synthesis around exercise.
In a ten-week study, 68 men received whey-casein protein blend or an equal amount of casein protein while undergoing lower-body resistance training (22).
Results showed that those consuming the whey-casein blend experienced less muscle fatigue compared to the casein group. Still, no differences in muscle size or strength were detected between the two groups.
The percentage of protein from whey and casein varies between products on the market. More often than not, the whey-casein blends contain more whey than casein.
For example, this whey-casein blend by Dymatize Nutrition has 75% whey and 25% casein protein per scoop, whereas this product by EAS Sports Nutrition does not list the percentage.
SUMMARYWhey-casein protein blends contain both whey and casein. Research suggests that they offer the same muscle-building properties as whey or casein protein alone.
4. Soy Protein
Soy protein is one of the most common plant-based protein powders on the market.
While it’s a complete protein, it’s low in a few key amino acids needed for building muscle.
Several studies in men have compared the effects of soy protein to whey or casein for increasing muscle protein synthesis.
Though whey and casein reign superior, soy can still stimulate muscle protein synthesis, making it a good plant-based alternative for men who follow a vegan diet or who don’t consume dairy (23, 24, 25, 26).
However, soy protein contains compounds called phytoestrogens.
These compounds are thought to lower levels of testosterone, leading many men to avoid soy protein for fear that it will compromise their hard work in the gym.
Despite this, the majority of the evidence suggests that men can safely consume soy protein in moderation without decreasing their testosterone levels (27, 28).
This product by NOW Sports contains 25 grams of vanilla-flavored soy protein per scoop. GNC makes an unflavored soy protein product ideal for baking or adding to smoothies.
SUMMARYSoy protein is a good plant-based alternative to dairy proteins for increasing muscle protein synthesis. In moderate amounts, soy protein does not appear to decrease testosterone levels in men.
5. Pea Protein
Similar to milk proteins, pea protein contains all essential amino acids, making it a complete protein.
However, the milk proteins have a much better amino acid profile for increasing muscle size and strength compared to pea protein (29).
Despite this, pea protein powder is one of the best plant-based alternatives for men who are vegan or have an intolerance or sensitivity to milk proteins.
One 12-week study in 161 men undergoing upper-body resistance training three times per week with a rest day between each session found that pea protein led to similar gains in muscle size and strength as whey protein (29).
These results suggest that pea protein is a good plant-based alternative to milk-based proteins for building muscle size and strength.
Naked Nutrition and Now Sports both offer a high-protein, low-carb pea protein powder.
SUMMARYFor men who follow a vegan diet or don’t tolerate milk proteins, pea protein is a good alternative for increasing muscle size and strength.
6. Rice Protein
Rice protein is another plant-based alternative to milk-based protein.
Despite being low in a few of the essential amino acids, rice protein can still help you build muscle.
In a study in 24 men, researchers examined the effects of rice protein or whey protein on muscle recovery and body composition (30).
The men completed a full-body workout three times a week for eight weeks. Following each exercise session, the men immediately consumed either a rice or a whey protein drink.
At the end of the study, men who consumed the whey protein drink gained 7.04 pounds (3.2 kg) of lean body mass while the men who drank rice protein gained 5.5 pounds (2.5 kg).
The whey protein group also increased their strength more than the rice protein group.
While this study had no placebo group, it does suggest that, while not superior to whey protein, rice protein can still help you gain muscle size and strength.
Similar to pea protein powder, Naked Nutrition and NOW Sports make a high-quality rice protein.
SUMMARYRice protein is low in some of the essential amino acids but can still help you gain muscle size and strength.
The Bottom Line
With the abundance of protein powders on the market, you may be wondering which one is best for you.
If you can tolerate dairy, whey, casein and whey-casein blends are the best options for losing fat and gaining muscle.
However, if you can’t tolerate dairy or if you follow a vegan diet, plant-based proteins like soy, pea and rice are the best protein sources.
For the best results, make sure to consume enough protein throughout the day and exercise at least three times per week.
What's the Difference Between Whey Isolate and Whey Concentrate?
There are several nutritional differences between whey isolate and concentrate. These differences are caused by the processing methods.
When the liquid whey is collected as a by-product of cheese or yogurt production, it undergoes several processing steps to increase its protein content (1).
After a sufficient protein concentration is achieved, the liquid can be dried to form whey concentrate powder that consists of up to 80% protein by weight. The remaining 20% of the whey concentrate powder contains carbohydrates and fats.
If different processing steps are used to reduce the fat and carbohydrate content of whey, a whey isolate powder containing 90% or more protein by weight can be produced (1).
Overall, the processing steps used in the production of whey isolate result in higher protein content and lower fat and carbohydrate content per serving.
However, the types of amino acids found in both forms of whey are virtually identical, since they are derived from the same proteins.
The table below shows the key differences between a standard whey isolate and whey concentrate supplement per 100-calorie serving:
Whey Isolate
Whey Concentrate
Processing
More
Less
Protein
23 grams
18 grams
Carbs
1 gram
3.5 grams
Fat
0 grams
1.5 grams
Lactose
Up to 1 gram
Up to 3.5 grams
Cost
Higher
Lower
In addition to having lower total carbohydrate content, whey isolate also has lower lactose content. This means that it could be a better choice for those who are lactose intolerant.
Nevertheless, the amount of lactose in both forms of whey protein is likely to be low enough for those who are lactose intolerant to use (4).
In addition to their nutritional differences, there are cost differences between these two types of whey. Generally, whey isolate is more expensive than whey concentrate.
While this makes sense based on the higher purity of whey isolate, taking a larger quantity of whey concentrate can bring you the same dose of protein, often at a lower cost.
SUMMARYThe main difference between whey isolate and concentrate is that whey isolate undergoes more processing, which results in a higher protein content with less carbs, lactose and fat. Whey isolate is typically more expensive than whey concentrate.
Many studies support the beneficial effects of whey protein for active people (5).
One study in 192 exercising individuals found that taking whey protein supplements, including whey isolate or concentrate, led to improvements in lean mass and strength (6).
However, despite the minor differences in nutritional content, there is not strong evidence to suggest that whey isolate and concentrate have different effects in your body.
In regards to protein, one of the most important factors is your total daily intake. What’s more, it is often recommended that the majority of daily protein intake comes from high-quality sourcessuch as dairy, eggs and poultry (5).
Both whey isolate and concentrate are high-quality proteins, and it is reasonable to expect that they will produce similar effects if an equivalent dose of protein is taken (3).
With that said, those who are limiting their fat, carbohydrate or lactose intake may prefer whey isolate since it is lower than whey concentrate in all three of these components.
It is also worth noting that many supplements contain a blend of proteins that includes both whey isolate and whey concentrate.
SUMMARYAlthough research supports beneficial effects of whey protein for active individuals, there is not clear evidence for differences in the effects of whey isolate and whey concentrate.
Whey protein consists of several fast-digesting proteins and is a common ingredient in dietary supplements. Two common forms are whey isolate and whey concentrate.
Whey isolate undergoes different processing than whey concentrate, which results in the isolate containing more protein with less carbs and fat per serving.
However, these nutritional differences are small, and there is not strong support for different effects of these two types of whey protein.
Whey isolate may be a good choice for those who are carefully limiting their fat, carb or lactose intake, though this form of whey is typically more expensive.
Taking a slightly higher dose of whey concentrate can result in getting the same total amount of protein as you would get from a whey isolate product, often at a lower cost.
Regardless of which type you use, whey is a high-quality protein that can help you reach your daily protein intake goals.
A commonly recommended dosage is 1–2 scoops (around 25–50 grams) per day, usually after workouts.
It’s 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.
Concerns about protein causing kidney damage and contributing to osteoporosis are unwarranted.
In fact, protein has been shown to protect against osteoporosis, while having no impact on healthy kidneys (56, 57, 58, 59).
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, isolate or hydrolysate may be more appropriate. Alternatively, you could simply avoid whey protein and eat other protein-rich foodsinstead.
But generally speaking, whey protein has an excellent safety profile and most people can consume it without problems.
SUMMARYWhey protein is very safe. A commonly recommended dose is 1–2 scoops (25–50 grams) per day.
The Bottom Line
Whey protein is an exceptionally healthy way to add more protein to your diet. It’s 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.
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 (38).
Beyond just muscle, strength and leanness, whey protein may provide numerous other health benefits.
This includes lowering blood pressure, blood sugar and reducing symptoms of stress and depression (39, 40, 41, 42).
It also protects against cancer, reduces symptoms of hepatitis, increases bone mineral density, improves immune function in HIV patients and increases the lifespan of mice (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53).
The fact that whey protein is very high in the amino acid cysteine seems to mediate many of these health benefits. Cysteine does this by raising levels of glutathione, the main antioxidant substance in your body's cells (54, 55).
SUMMARYWhey is high in essential amino acids and other healthy nutrients. It’s also rich in the amino acid cysteine, which raises levels of the antioxidant glutathione and leads to many health benefits.
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 (29).
Protein can boost energy expenditure by 80–100 calories per day, and make people automatically eat up to 441 fewer calories per day (30, 31, 32, 33).
In one study, eating 25% of the daily calories in protein cut cravings by 60% and reduced the desire for late-time snacking by half (34).
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 (3.5 kg) while increasing lean muscle mass (35).
If you're trying to lose weight, a whey protein supplement can help you both lose weight and hold on to your muscle (36, 37).
SUMMARYProtein has been shown to aid weight loss by boosting metabolism and reducing appetite. Whey protein can help increase fat loss while preserving lean muscle mass.
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 (12).
Leucine: It’s high in the amino acid leucine, which is known to stimulate muscle protein synthesis at the molecular and genetic level (13, 14).
Fast absorption: Whey protein is absorbed and utilized very quickly compared to other types of protein (15).
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 (16, 17, 18, 19).
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 (20).
When compared to other types of protein, such as soy protein, whey protein has usually performed slightly better (21, 22).
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 (23, 24, 25, 26, 27).
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 (28).
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 — all high in quality protein — the benefits of adding whey will probably be minimal.
SUMMARYThere is a lot of evidence that whey protein is effective at increasing muscle and strength gains, though some studies find no effect.
