These days, protein powder is everywhere. Do a quick Google search and you’ll find whey, casein, hemp, chickpea, pea, soy and — for the adventurous consumer — cricket protein. And that’s just on page one. But is whey protein good for you?
Naturally, each protein claims to be the best protein. But come on. They can’t allbe the best.
While the FDA may be slow to verify the health claims for these supplements, researchers are not. When you review the scientific studies on whey protein — a protein supplement derived from cow’s milk — it seems to shine a little brighter than the rest.
The Basics: Is Whey Protein Good for You?
You probably already know that whey helps with muscle growth and recovery. That protein shake at your gym? It probably contains whey.
What you may not know are the non-muscle-related benefits of whey protein. Healthy weight loss, cardiovascular health, immune function, cancer mitigation, antioxidant support, liver health — the list goes on. These benefits come, in large part, from a handful of peptides and proteins found in whey supplements.
This guide explains more about these compounds, along with the many benefits (and a few possible side effects) of whey protein supplementation. So when someone asks “is whey protein good for you?” you’ll be confident in your response.
Whey Protein Powder Basics
Whey isn’t vegan as it comes from milk — primarily from cow’s milk, but sometimes it’s from sheep or goats. Milk contains two types of protein: casein (about 80%) and whey (about 20%)[*].
When you separate dairy solids from the liquid, you get whey (the liquid) and casein (the solid).
Depending on the method of extraction and filtration, you then get one of three products:
- Whey protein powder: This is used mostly in food products and is the least concentrated form of whey with lots of lactose.
- Whey protein concentrate (WPC): This comes in supplement form and is a moderately concentrated form of whey with less lactose.
- Whey protein isolate (WPI): This is the purest supplemental form with the highest concentration of bioactive compounds and protein, and trace amounts of lactose.
The whey protein supplements discussed in this article are primarily whey isolates. As far as protein powders go, whey protein isolate is an extremely high-quality option. It’s also the best option for people with lactose sensitivity.
This is not a subjective statement. According to published research, whey protein is an efficient and digestible source of protein for humans[*].
Protein efficiency is a measurable thing. It’s measured by how much an animal grows when fed a given protein — and anything above a 2.7 is very digestible. For reference, soy protein scores a 2.2 while whey protein scores 3.2 — the highest protein efficiency score after eggs.
Is Whey Easy to Digest?
Technically, whey is a dairy product. And dairy is tough to digest for some people. Whey isolate, however, is largely free of two compounds responsible for most dairy intolerance: lactose and casein.
- Lactose: A milk sugar that many people (5-15% of those with Northern European heritage, by one estimate) can’t tolerate. Lactose intolerance typically manifests as digestive symptoms like bloating, cramping, diarrhea, or nausea[*].
- Casein: This milk protein may also cause symptoms ranging from stomach pain to gas. In some people, casein appears to provoke intestinal inflammation[*]. If you don’t tolerate dairy well, casein may be to blame.
In whey isolate powder, however, most of the lactose and casein are filtered out. So those with dairy intolerance (not dairy allergy) may be in luck.
That’s probably why whey scores a 1.00 (the highest possible score) on protein digestibility — which is measured by examining amino acids in feces. For reference, black beans scored a 0.75 and gluten a dismal 0.25.
Amino Acids and Other Compounds in Whey
Like other protein powders, whey protein is made up of amino acids. Amino acids are building blocks that form all protein molecules, plus the structure of your tissues, including your muscles, skin, hair, nails.
Whey contains all 9 essential amino acids, plus muscle-building branched-chain amino acids, or BCAAs. These amino acids are “essential” because your body can’t synthesize them on its own — you have to get them from food or supplementation.
BCAAs account for 35% of the protein in muscle tissue, and are best known for their anabolic (growth-promoting) effects[*].
There are three main types of BCAAs: leucine, isoleucine, and valine — and each play a role in muscle growth and recovery. Of the three, leucine is the key player in muscle protein synthesis[*] and whey is packed with leucine.
Whey is also full of cysteine — an amino acid precursor that helps produce your master antioxidant, glutathione. As such, consuming whey boosts glutathione production[*].
In addition to BCAAs and cysteine, whey contains a long list of beneficial bioactive compounds including[*]:
- Immunoglobulins (IGG, IGA)
Whey for Muscle Growth and Recovery
If you want to build and repair muscle, you need amino acids circulating in your blood. And for that, you’ll need adequate protein.
Recall that whey protein is high in BCAAs, easily digestible, and proven in animal models to be among the most efficient proteins on the planet. For these reasons, researchers love using whey in human trials on exercise and recovery.
How does whey help you build muscle? It does this by promoting positive net protein balance in muscle tissue.
Basically, net protein balance equals protein synthesis (muscle building) minus protein breakdown (muscle breakdown)[*].
This means that if muscle synthesis beats out muscle degradation, your muscle mass will grow.
How It Helps Build Muscle
This is where whey protein comes in. Researchers fed 12 young, healthy men either whey or carbohydrates, had them lift weights, then measured muscle growth and recovery markers at 10 and 24 hours post-workout.
The whey-fed group, compared to the carb-fed group, had more strength and power at both time intervals post-training sessions[*]. At 24 hours, the whey-fed group could also perform more reps before muscle failure. When it comes to muscle recovery and athletic performance, whey works.
Older adults can also benefit from whey’s anabolic properties. When you age, you lose significant muscle mass with the passage of each decade. This condition, known as sarcopenia, increases your risk for chronic disease and drastically lowers quality of life[*].
Fortunately, it appears that resistance training — when combined with whey protein supplementation — can help prevent sarcopenia. In one study, scientists supplemented 70 older women with whey during a 12-week weight training program. Whey taken either before or after resistance exercise led to significant muscular gains[*].
Another group of researchers showed that whey protein outperformed casein for muscle growth in older men. They attributed whey’s victory to its superior digestibility and high levels of leucine[*].
It’s no surprise that bodybuilders use whey. It has excellent protein content that is great for building muscle. But what about losing weight?
Whey for Lean Muscle Mass and Weight Loss
In the ideal weight loss program, a person loses fat while maintaining lean muscle mass.
What’s a proven way to lose weight? Simply reduce carbs, then replace those carbs with fat or protein. This, along with staying at a reasonable caloric intake should help most people shed fat.
In one trial, researchers advised 65 overweight people to eat either a high-carb or high-protein diet. After six months, the high-protein group had lost significantly more weight than the high-carb group. Not exactly a tightly controlled experiment, but still some data to consider[*].
Here’s the thing:In weight loss programs, the type of protein supplement matters — and to maintain muscle during these weight loss programs, no protein source has proven more effective than whey.
So is whey good for you? Well, as you know, whey contains lots of leucine — a BCAA critical for muscle maintenance. Plus, it’s easier to digest than most other proteins.
In a 2017 study, researchers recruited 34 women coming off gastric bypass surgery and randomized them to eat two weight-loss diets: a low-calorie diet with whey, and a low-calorie diet without whey. The whey supplemented women lost more weight, and crucially, more body fat than the control group[*].
Another proven weight loss diet is a high-fat, low-carb keto diet. And as it turns out, whey protein is a valuable tool in the keto weight loss toolkit.
Whey and the Keto Diet for Weight Loss
The ketogenic diet is known for helping people shed fat[*]. When you switch your energy source from glucose (carbs) to ketones, your body doesn’t just burn the fat you eat, it starts burning stored fat as well.
You also eat less on the ketogenic diet. On keto, you’ll stay fuller for longer thanks to[*]:
- Decreased ghrelin: Your hunger hormone
- Increased cholecystokinin (CCK): A hormone that binds to your brain to reduce appetite
- Decreased neuropeptide Y: A brain-based appetite stimulant
Increased Fat Burning
The ketogenic diet, by definition, is a high-fat, low-carb, moderate-protein diet. But that doesn’t mean you should avoid protein altogether. Many keto dieters are concerned about a biological process called gluconeogenesis, but you shouldn’t be.
Protein is an important part of any diet and weight loss program, keto included. In fact, you need a moderate amount of protein to maintain a lean, muscular body composition[*]. One solution is to add whey protein to your keto diet in addition to MCT oil and nut butter.
In a pilot study, researchers put 25 healthy people on one of two diets: a ketogenic diet (with whey protein supplement) and a calorie-restricted diet. Although both groups lost weight, the keto with whey group maintained more lean muscle than the low-calorie group[*]. Good to know for preventing muscle wasting during weight loss.
Another group of researchers took keto-induced weight loss to another level — dripping whey protein directly into the GI tracts of 188 obese patients kept (via carb restriction) in a mildly ketogenic state. Over the ten-day program, these patients lost significant body weight — and this was fat loss, not muscle loss[*].
But for those with metabolic disorders, muscle maintenance is not the only benefit of whey.
Whey for Metabolic Disorders
Recall that whey protein helps you maintain lean mass during weight loss. Whey also appears to improve markers of metabolism — at least in those with metabolic issues, including obesity and diabetes.
Wait a minute though. Doesn’t eating whey protein make you bigger?
It can if you happen to be a growing child or an athlete[*]. But in obese people and type 2 diabetics, whey protein has a different effect. To understand this effect, you need to understand how metabolic disorders work.
How Metabolic Disorders Work
Obesity and type 2 diabetes are both metabolic disorders that stem from problems with insulin — your blood sugar regulation hormone. And what creates problems with insulin? Chronic high blood glucose.
When you eat a high-carb diet, your blood glucose stays chronically elevated, and your pancreas has to release more and more insulin to get glucose out of your blood and into your cells. Eventually, your cells stop listening to insulin and stop taking up glucose. Because of this, your pancreas pumps out even more insulin to handle the hyperglycemic situation. And the cycle continues.
This cycle is called insulin resistance— and insulin-resistant people store fat rather than burn fat. And it’s a short hop, unfortunately, from insulin resistance to metabolic syndrome.
Whey may help.
In one study, researchers gave obese people whey supplements for twelve weeks — and saw significant improvements in fasting insulin levels[*].
In another, type 2 diabetics had significantly better post-meal glucose and insulin responses when they supplemented whey before a high-carb breakfast[*].
Whey for Chronic Disease
Whey’s high digestibility and stellar amino acid profile make it a darling of the protein supplementation world. Many researchers look to whey for help with chronic diseases. Here are a few results:
- Cardiovascular disease: In those with hypertension (high blood pressure), whey protein supplementation lowered blood pressure, improved lipids, and enhanced markers of blood vessel function[*].
- Liver disease: Whey protein supplementation improved markers of non-alcoholic fatty liver disease (NAFLD) in obese women, possibly due to enhanced glutathione (antioxidant) production[*].
- Cancer: The lactoferrin in whey protein suppressed colon cancer cell growth[*] — and the cysteine in whey (due to its effect on glutathione) may reduce tumor formation in humans[*].
- Gastrointestinal disorders: In people with Crohn’s disease, whey reduced intestinal permeability, or leaky gut[*].
- Cognitive decline: While not exactly a chronic disease, whey supplementation tended to improve verbal fluency in middle-aged to older adults[*].
- Immune disorders: Results in mice suggest that whey protein is useful for enhancing immune function and preventing autoimmune disorders[*].
Whey Protein Health Benefits
As a reminder, here are the most well-known bioactive compounds in whey, along with brief descriptions of their researched benefits.
- BCAAs: The amino acids leucine, isoleucine, and valine for muscle growth and recovery
- Cysteine: An amino acid used to form glutathione — your body’s master antioxidant[*]
- Lactoferrin: A milk protein shown to enhance bone health and prevent iron overload[*][*]
- Alpha-lactalbumin: A milk protein with beneficial effects on brain health and neurotransmitters[*]
- Beta-lactoglobulin: A milk protein that enhances immunity and alleviates allergies[*]
- Immunoglobulins (IGG, IGA): Immune-boosting compounds that help fight infection[*]
- Lysozyme: An enzyme that kills bacteria by destroying their cell walls[*]
- Lactoperoxidase: An enzyme that helps produce compounds that kill bacteria[*]
There are more than eight compounds in whey, but those are the big ones.
By now you may be wondering: is whey protein for everyone?
Potential Side Effects
Most people can tolerate whey protein, especially whey protein isolate — the purest form of whey possible. In this form, you’re getting all the benefits of whey with only trace amounts of lactose and no casein.
If you still feel strange or have a reaction after your whey protein shake, it’s likely due to one of two things — lactose intolerance or a dairy allergy.
A large chunk of the population can’t tolerate dairy, and lactose is often to blame. Even though whey isolate extraction removes most of the lactose from milk, trace amounts of this milk sugar remain.
Depending on the person, this bit of lactose can cause gut issues such as gas, bloating, stomach pain, or bowel trouble. As with all things nutrition, it’s an individual thing.
People with dairy allergies are typically allergic to the milk protein casein, alpha-lactalbumin, or beta-lactoglobulin[*].
This isn’t medical advice, but those with dairy allergies would do well to avoid all milk products, including whey protein.
One more thing. Whey itself doesn’t appear to cause kidney or liver damage, but those with existing conditions may want to avoid a high-protein intake, whey or otherwise[*].
Is Whey Good for You?
Whey is good for most people unless you have a strong sensitivity to lactose (remember, there are only trace amounts of lactose in whey protein isolate) or you have a dairy allergy.
Otherwise, supplementing with whey protein powder delivers many health benefits, including:
- Ease of absorption and digestibility
- Enhanced muscle growth and recovery
- Preservation of lean mass during weight loss (on the keto diet, for instance)
- Improved antioxidant response via enhanced glutathione production
- Better immune system function due to compounds like lactoferrin, alpha-lactalbumin, and beta-lactoglobulin
- Mitigation of metabolic disorders like obesity and type 2 diabetes
- Promise for improving chronic diseases like cancer, liver disease, and GI disorders
- Lower blood pressure and improved vascular health in hypertensive people
Pretty impressive, right? Just remember that although many proteins claim to be the best, only one is telling the truth.