Everything you need to know about whey protein

Learn how to select the best whey protein powder for you

  • How much, how often, and when: make the best use of your whey protein.
  • Concentrates, isolates, hydrolysates: when they matter, and why they matter.
  • Whey sourcing and processing: how they affect the protein — and your health.
  • Discover what else may be in your powder — and if you want it there or not.
  • Understand the legal loopholes supplement companies use to trick you.
  • Select the best whey protein for your needs … and save money!
iPad version of Definitive Guide to Whey Protein
  • The New York Times
  • The Washington Post
  • Men's Health
  • BBC
  • The Guardian
  • Medpage Today
  • Forbes Magazine
  • The Academy of Nutrition and Dietitics - AND

Why is it so important to choose the right whey?

Do you get the most out of your whey protein?

You know protein is essential for good health. It helps build muscle and burn fat. It’s used to make hormones, enzymes, and neurotransmitters. There’s a reason it’s the most essential macronutrient.

But let’s face it: when life gets busy, preparing high-protein meals can be a challenge.

Enter protein powders. They make it easier to hit your optimal protein intake. Pick your favorite flavor, add water, and voilà. Convenience is king — that’s why Americans spend nearly $5 billion on protein powders every year.

Of all those powders, the best selling is whey protein, and for good reason:

  • It’s inexpensive.
  • It has high bioavailability and a great amino acid profile.
  • It mixes easily and comes in many flavors. (Do you like piña coladas? That’s actually a whey protein flavor, believe it or not!)

But, flavors aside, are all products the same? No.

So — what makes a good-quality whey protein powder?

And what makes a powder the best for you?

You likely have some idea already as to what your ideal powder should be. It should digest easily and absorb well, that’s a given. You might also want it free of lactose or rich in certain immunoglobulins. And you don’t want to pay for extra, useless ingredients, or settle for the cheapest option when paying a bit more could get you a much higher quality powder.

But, that’s the question: is an isolate worth the extra money over a concentrate? What about whey from grass-fed cows? Is cold-processed whey less denatured, as the sellers claim, and native whey more anabolic? Is organic better for your health?

There are dozens of important health issues to consider when selecting a protein powder, from heavy-metal contamination to protein spiking. And before you even get to picking a product, you should know how whey compares to other powders, from casein and plant-based proteins to BCAAs and EAAs.

Choosing a product would be easier if you could trust the labels, but with so much money at stake, many claims are supported by weak evidence (such as mouse studies, test-tube experiments, or less-than-rigorous human trials) or are simply made up.

Make sure you get the right whey for YOU.

With the Definitive Guide to Whey Protein, Examine.com has answered nearly every single question there is on whey — all the hundreds of questions we’ve received over the years. Using our meticulous science-based approach, you can easily and confidently navigate the market.

Our guide can help you choose the best product for you.


What you’ll discover in the Definitive Guide to Whey Protein

Answers to the top questions on protein

How much protein do you need, and how much is too much? When are whole foods better, and when are powders? How does whey compare to other proteins, whether animal or plant based?

How to optimize your protein intake based on your goals

Are you looking to build muscle? Burn fat? Maintain your health as you get older? If so, how much protein should you get per meal? At breakfast? At bedtime? Before and after training? And how much can you really digest in one sitting? Learn to fine-tune your protein requirements based on your health goals so you always get the right amount.

How to make sure you buy the best whey for your money

We break down what you need to look for when buying a whey protein. Understand the tricks manufacturers use to charge you extra; decide what ingredients you really need, and which you’re better off without; learn how to look over a label and immediately know what matters.

The differences between the various types of whey protein

How is whey processed into a concentrate, an isolate, or a hydrolysate — and what practical difference does it make?

A primer on the advanced topics

How is your whey affected by its sourcing (native, organic, grass-fed, pasture-raised …) and processing (pasteurization, filtration, spray drying …)? What are the pros and cons of the different filtration methods (ultrafiltration, crossflow filtration, ion exchange …)? How can you ensure that your whey hasn’t been denatured, so you can benefit from the health-promoting effects of its bioactive peptides?

The truth about additives

A protein powder is seldom composed of just protein. Many ingredients can be added to prevent the product from clumping, to give it a smoother texture when mixed with water, to make it easier to digest, and of course, to improve its appearance and taste. We’ll review a variety of additives, including different sweeteners and colorants, both natural and synthetic. You’ll learn the pros and cons of each — and the health risks attached to some.

How casein compares with whey protein

Whey digests fast; casein, slowly. Is there a time when casein is superior to whey? Or should you blend the two proteins — and if so, in which ratios? What are the bioactive peptides in casein? Is A2 β-casein really superior to A1 β-casein?

If you should consider supplementing with BCAAs

Whey protein is rich in essential amino acids, notably BCAAs. But as a standalone supplement, how do BCAAs compare with whey protein? Have they been shown to increase or preserve muscle mass? Can they benefit muscular strength, function, or recovery? Can they, in some circumstances, replace or complement your whey protein?

If other amino acids can make a difference

While whey protein is naturally rich in BCAAs, some amino acids not found in whey may have been added to your powder. Can glutamine promote recovery? Can taurine increase endurance? Can beta-alanine give you an edge when you train or compete? Can HMB promote muscle gain or stave off muscle loss? Can some amino acids raise your levels of nitric oxide, thereby promoting nutrient delivery, muscle growth, and exercise performance?

Ready to get started?

Get the Definitive Guide to Whey Protein

Benefit from free lifetime updates. We are a research organization: as we keep up to date with the latest research, we’ll revise your guide and add to it so you’ll stay up to date too.

Here’s a tiny sliver of the hundreds of questions our guide answers using the latest peer-reviewed research:

  • How much protein do you need for your age, weight, and fitness goal?
  • How much protein should you get per day? Per meal? Per training session?
  • Should you take whey protein before or after training? What’s the “anabolic window”?
  • How fast does whey protein get digested? At bedtime, should you switch to casein?
  • Whey concentrate, isolate, hydrolysate — what are the practical differences?
  • What are the various ways to process whey, and can they denature the protein?
  • Native, organic, free-range, grass-fed: how does sourcing change your whey?
  • What added ingredients are in your powders? Are there any you should avoid?
  • What legal loopholes do companies use to trick you? What is “protein spiking”?
  • Can EAAs, BCAAs, leucine, or other AAs complement or replace whey protein?
  • Whey-based or plant-based powders, or whole foods: what are the pros and cons?
  • What benefits has whey protein research found in women? In children? In seniors?

Click here for a sneak peek

Benefit from decades of important research without spending decades poring over studies.

Who is this guide for?

Anyone who is taking whey, is considering taking it, or is interested in it for the sake of their patients, athletes, clients, friends, or family. Whether you’re male or female, young or old, active or sedentary, under- or overweight; whether your goal is to build muscle, lose fat, or just be the healthiest you can be; our guide can help you choose the best product for you — and take full advantage of every gram.

You want to lose weight

Whey protein is one of the few supplements proven to work in human studies (and not just, you know, in test-tube studies of mouse fat cells). Our guide will help you include in your diet the ideal amount of whey protein to enhance your weight loss — and ensure that most of the lost weight will be fat, not muscle.

You want to build muscle

In both men and women, whether with or without training experience, research shows that adding whey protein to exercise accelerates fat loss and muscle gain and reduces muscle soreness (soreness is especially common in people who’ve just started working out). Our guide will help you choose between products and fine-tune your protein protocol to take full advantage of your efforts at the gym.

You’re a health professional

Whether you’re a doctor, dietitian, coach, or personal trainer, your patients, athletes, or clients probably turn to you for advice on supplements in general and protein powders in particular — and you want to give them the very best guidance in this area too.

Our guide will provide you with all the information you need, based on the latest scientific evidence. The supporting studies are all clearly referenced.

You’re a nutrition nerd

If you’re the kind of person who wants to know everything they can about a topic, and whey protein is something that intrigues you, this is the perfect guide for you. We go deep into the science. Does cold-processed matter? How about grass-fed? Type of sweetener? Filtration method? Our users asked us over a thousand questions about whey, and we set out to answer them all.

You’re a bodybuilder or fitness model

If you’re a bodybuilder, you already know about many kinds of protein powders and probably blend a few or use different ones at different times. You’re also more likely to want to get an edge with a special protein powder, even if it empties your wallet.

Our guide will help you decide if a product is worth its higher price tag. It will help you adjust dosing and timing to ensure maximal muscle protein synthesis (anabolism) and minimal muscle protein breakdown (catabolism). It will help you bulk with minimal fat gain and lean down with minimal muscle loss.

If you’re a fitness model, however, you can’t afford to alternate bulking and cutting cycles. You need to keep in shape — to keep your muscle mass high and your fat mass low — year around. Our guide can help you fine-tune your intake to achieve this result, and maybe even improve on it: studies have shown that whey protein can help build muscle and lose fat over the same period of time.

You’re an athlete

In strength athletes, whey protein increases neuromuscular efficiency as well as muscle mass. But what about BCCAs? Or beta-alanine? Can they really give you an edge when you most need one?

In endurance athletes, whey protein promotes recovery and muscle repair and reduces muscle soreness. But what about glutamine? Can it also promote recovery? And taurine, can it really boost your performance?

You're a vegetarian

It is harder to get enough protein from a plant-based diet:

  • The whole foods richest in protein are all animal based.
  • Proteins from plant-based whole foods have lower bioavailability.
  • Proteins from plant-based whole foods are seldom complete proteins.

Therefore, if you’re vegetarian, a whey protein powder can really make your life easier. Our guide will help you select the right one (from pasture-raised cows?) and determine how much to take to complement the protein in your plant-based diet.

(Whey is a protein in milk, however, so if you’re vegan, this guide isn’t for you!)

You’re pregnant or lactating

Studies show that you need more protein when you’re pregnant or lactating, to ensure optimal health for you and your baby. But how much more, and is whey protein safe? And what about all the other ingredients commonly found in whey protein powders?

You’re a senior

It’s unfair, but the older you get, the more important protein becomes. A whey protein powder can slow, prevent, and even reverse sarcopenia (age-related muscle loss), even in seniors who don’t exercise.

Alas, it’s too late to build muscle you didn’t have as a youth — right?

Wrong! Studies show that you can increase your muscle mass even in your late years, as long as you do resistance training and get enough protein. The catch is that you need more protein than a youth to jumpstart the muscle-building process. So whether your goal is to keep healthy as you age or get fitter than you ever were, our guide can help you.

Everything you need to know about whey protein — right at your fingertips

Whey protein is popular, and for good reason: no other supplement has been researched to such an extent, and proven so consistently beneficial, in so many populations — athletes, seniors, overweight people, postmenopausal women, the list goes on and on.

It took us thousands of hours over several years to parse the evidence.

It took us over a year to write the Definitive Guide to Whey Protein.

If you take whey protein, our guide will help you.

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What information is worth your time?

  • Expert information. Our team of researchers combines degrees in public health, nutrition, exercise science, biomedical science, molecular biophysics, neuroscience, chemistry, and more, and we each have our own professional network to call upon whenever we need to contact the top experts in any given field.
  • Unbiased information. We do not sell supplements or advise supplement companies. We do not accept sponsorship, donations, or even ads on our website. Research is all we do. Our publications are based strictly on the latest scientific evidence, and they’re our sole source of revenue.
  • Up-to-date information. The evidence evolves. The latest research can change our outlook even on the best-studied supplements. Which is why your Definitive Guide to Whey Protein comes with free lifetime updates. As the scientific evidence grows, so will your guide.

Examine.com saves you money

Nowadays, Americans spend more than $12 billion a year on supplements, not even counting vitamins and minerals. The average buyer spends over $350!

And think: $350 per buyer is just an average; included are the many people who take only a couple of fish oil softgels a day. If you supplement with protein, you probably spend a lot more than half a grand a year without even noticing, and protein powders can easily be your largest expense. In fact, as we mentioned near the top of this page, Americans spend nearly $5 billion a year on protein powders — more than 80% of which is whey protein.

With billions on the line, competition is fierce. So how does a company make its whey protein stand out? Most often, by adding various ingredients (whether useful or not) and by increasing its marketing budget (together with its price). Notably, they’ll buy ads on websites that publish health-related articles. But how can you trust those articles, then? Would you trust someone who promises to tell you the truth about cars but is sponsored by a car company?

That’s why Examine.com doesn’t sell ads: so we can examine the scientific evidence and never feel tempted to tweak or filter it. Our Definitive Guide to Whey Protein will tell you clearly which claims are backed by human studies — and which are not. You will get straightforward, complete answers to the hundreds of whey-related questions we’ve received over the years.

For less than the cost of a tub of whey protein, you will learn to see through the marketing malarkey to select the best powder for your needs, and you will learn to make the best possible use of this powder through optimal dosage and timing.

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Founded in 2011, Examine.com is an education company led by a team of experts — PhDs, researchers, pharmacists, and more. With over 2.5 million visitors each month, our website is the trusted resource on nutrition and supplement research.

Anyone who is taking whey, is considering taking it, or is interested in it for the sake of their patients, athletes, or clients. Whether you’re male or female, young or old, active or sedentary, under- or overweight; whether your goal is to build muscle, lose fat, or just be the healthiest you can be; our guide can help choose the best product for you — and take full advantage of every gram.

Our goal is to update the Definitive Guide to Whey Protein with new scientific evidence at least once a year.

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