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5 Reasons Whey Isolate Protein Powder is Optimal for Building Muscle

by Trevor Hiltbrand | Reviewed by Advisory Board

5 Reasons Whey Isolate Protein Powder is Optimal for Building Muscle

When it comes to building muscle, there are few foods or supplements that are more powerful than whey isolate protein powder.

Not only is whey protein one of the most highly researched and tested protein supplements on the market today, but it is also proven to improve satiety (keeps you feeling full throughout the day), promote weight loss, and maximize muscle growth. For all of those reasons, whey protein is a must-have for any athlete, bodybuilder, avid gym-goer or anyone looking to improve their physique.

Before we dive into the science and benefits of supplementing with whey isolate protein powder, let us first explain what it is, and also how it differs from whey protein concentrate. 

What is Whey Protein?

protein powder closeupprotein powder closeupWhey protein is a mixture of proteins isolated from whey--the liquid part of milk that separates during cheese production. Food products that contain whey include milk, cheese, yogurt, protein powder supplements, and even protein bars.

Have you ever opened a container of your favorite yogurt and noticed some clear liquid floating on the top? That clear liquid is whey.

In the old day's companies that produced cheese used to throw out the whey during the manufacturing process because they considered it waste, but once they discovered its strong commercial value, throwing it out became a thing of the past.

Plain whey protein doesn’t have much taste, but when combined with natural flavoring agents like vanilla, chocolate, or even fruit, it is a great addition to any smoothie, or pre/post-workout shake. The final product is what you see in stores in powder form.

The Difference Between Whey Isolate Protein and Whey Concentrate

The key difference between whey isolate and whey concentrate is what occurs during the manufacturing process. Put simply, whey isolate goes through a more intense processing phase than its counterpart, whey concentrate.

In the case of whey isolate protein, many of the carbs and fats are removed, leaving primarily protein content. With whey concentrate, most of the carbs and fats remain.

For people who are actively counting macros and are conscious about maintaining an aesthetic physique, whey protein isolate may be the best of the two options simply because it allows a person to consume higher protein content in a shake and save their carbs and fats for whole food meals.

Now that you know what whey protein is and how it’s made, let’s discuss what you really came here for--the reasons why it is optimal for helping you build more muscle mass.


#1:  Whey Protein Contains the Building Blocks of Muscle Building

Let’s get scientific for a second:

Muscle is tissue that is made up of protein. Muscle tissue is made up of fibers, and those fibers comprise chains of amino-acid molecules.

If you’re looking at the big picture of muscle building, there are 20 amino acids that assist the body in the protein-building process. These 20 amino acids are split up into two categories:  

11 non-essential amino acids (these are produced naturally by the body)

9 essential amino acids (these are not produced naturally by the body)

Because there are 9 essential amino acids that cannot be produced by the body, we must obtain those amino acids through food or supplementation. Foods like animal meat, eggs, some plant proteins, and dairy are considered complete proteins, meaning they contain all 9 essential amino acids and are ideal foods to consume if the goal is to maintain or build muscle mass.

So, how does whey isolate protein fit into the big picture of muscle building?

Whey protein contains all 9 essential amino acids, including an extra high dose of the amino acid leucine, which has been shown to effectively stimulate muscle protein synthesis and help build more muscle mass.

A 2003 study noted that whey protein isolates are the purest protein source available for consumption. Unlike other foods and protein supplements, whey protein isolates contain protein concentrations of 90% or higher. And like we mentioned previously, it also contains one of the highest concentrations of branched chain amino acids (BCAA’s) of any protein product, which help maintain and build muscle tissue and prevent catabolic activity during high-intensity resistance training sessions.

protein quality rankings chart


#2:  Whey Protein is Absorbed Rapidly in the Body

If your end goal is to build muscle mass, it’s important to pay close attention to the quality of protein you are consuming on a daily basis, especially in the 2-3 hours before and after your gym session.

For the body to utilize protein, the small intestine must absorb the protein and transport it to the blood, where it can then be circulated to the various tissues in the body. Some protein sources (like animal meat for example), are difficult for the body to break down. In some cases, it can take hours for the body to break down a particular protein source.

In the time before and after your workout, your body prefers to have a rapid-digesting protein source over a slow-digesting source.

amount of amino acids absorbed over time


Have you ever tried to ingest a whole T-Bone steak and then go to the gym for a lifting session 30-45 minutes later? You’d be crazy to do that. We dare you to try.

If you want to maximize protein synthesis and ultimately build more muscle in the long run, it’s better to consume a fast-digesting protein before and after your workout, than to try and eat a meal that consists of whole foods.

Whey protein’s solubility allows it to be absorbed immediately after it is ingested. The result is a spike in amino acid levels which leads to protein synthesis.

Protein synthesis is the process by which amino acids are linearly arranged into proteins through the involvement of ribosomal RNA, transfer RNA, messenger RNA, and various enzymes.  Put plainly: without maxing out muscle protein synthesis you will never see the muscle gains you hope to achieve.

Research shows that individuals who consume 20-25 grams of fast-digesting protein (like whey), may see an increase in muscle building through the process of muscle-protein-synthesis.  This is true in the post-workout window (2 hours after workout), but is also true for up to 48 hours after an intense resistance training session. Even if you consume a serving or two of whey protein 24-48 hours after your workout, you are still seeing a benefit in terms of muscle growth and recovery.

In addition to digesting very quickly, whey protein is especially high in the amino acid leucine, which helps to promote muscle-protein-synthesis and aid in recovery. Whey protein has much higher leucine content than other forms of protein, including casein, making it ideal for those trying to pack on muscle mass.

Does a Protein’s Rate of Ingestion Really Have an Impact on Muscle Growth?

In 2010, a research study was conducted on ingestion rate of protein and its effect on protein supplementation. In the study, eight moderately active young men were instructed to drink approximately 25 grams of whey protein after completing a 10-rep max leg extension exercise on two different occasions.

The study was separated into two trials. During the first trial the study participants were instructed to consume the entire 25 grams of whey protein at once, and in the second trial, they drank 2.5 grams 10 times over a 200-minute period (to mimic the slower absorption of casein or milk protein).

What were the results of the study?

Both trials (chugging all of the protein and dosing it over a period of time), resulted in increased essential amino acids and leucine in the blood.

When the whey protein was consumed all at once, it did result in a higher peak level of essential amino acids and leucine compared to when the protein was dosed over an extended time period. And while leucine levels are nice to look at, what avid gym-goers are really concerned about at the end of the day is what is happening with protein synthesis within the muscle.

With regard to the research study that we just mentioned, drinking the whey protein all at once increased protein synthesis much more than spacing out the protein over a few hours.

If building muscle is your goal, it’s best to consume 20-25 grams of fast-digesting protein, preferably from whey, immediately after you complete your lifting session. Because whey is one of the fastest-digesting protein sources available, it makes sense to consume it after every workout.


#3:  Whey Increases the Release of Anabolic Hormones


man hydrating

Researchers spend a lot of time and energy looking at the best way to consume protein before a workout, after a workout, and throughout the day. They evaluate everything from protein timing, protein quantity, and the types of protein that will lead to the greatest amount of muscle growth in fit individuals.

Protein timing is one strategy that high-level athletes and fitness enthusiasts often focus on to improve the body’s adaptive response to intense exercise. One known benefit of protein timing is its impact on growth hormones. The more growth hormone an individual has present in their body, the more muscle mass they will maintain.

In a study on the effects of whey protein on growth hormone levels, researchers studied a group of individuals that consumed whey protein orally for 6 weeks, combined with resistance training three times per week, to see if there would be a significant increase in the production of growth hormone. The end result:  The group that consumed whey protein in combination with regular exercise had higher growth hormone levels and built more muscle mass than the control group who did not consume whey protein. Both groups performed three resistance training sessions each week.

Another study shows that dairy-based protein powders (like whey), are able to increase levels of IGF-1 in the body and support the expansion and multiplication of muscle cells. IGF-1 is a hormone in the body that is correlated with Human Growth Hormone (HGH), and is responsible for the muscle growth effects of HGH. When you increase HGH levels in the body, you will also increase IGF-1.  

There are plenty of other published studies that prove the benefits of consuming whey isolate protein powder in combination with exercise. The good news is these studies support the fact that whey protein and exercise may have a significant impact on anabolic hormones and muscle strength.

If you want to enhance muscle strength and anabolism, whey needs to be one of your go-to protein sources, especially within the pre and post-workout window.


#4:   Whey Helps you Hit Your Daily Protein Goals (essential for mass building)

Whether you are a professional athlete or an “average Joe” that is putting in time at the gym to improve your overall body composition, consuming enough protein each day is one of the keys to success.

The American College of Sports Medicine recommends that individuals who want to gain muscle mass need to be consuming around .5 - 1 gram of protein per pound of body weight each day. If you are a 200-pound male, that means you could be consuming as much as 100-200 grams of protein per day. That’s a lot of chicken and fish!

It’s unrealistic to expect anyone to consume 200 grams of protein from whole food sources like chicken breast, whole eggs, steak, fish, etc every single day. This is where supplementation with a high-quality protein source (like whey isolate), becomes so crucial.

If you’re a person who likes to consume a few whole food meals each day, try using a whey protein powder in between meals to sneak in a few extra grams of protein throughout the day. You’ll find that not only is whey protein great for building muscle, but 1-2 shakes a day will also help you stay full because it has been shown to have a significant impact on satiety. Satiety is important because it helps prevent chronic overeating or binging, which is a common struggle among bodybuilders and the general population.


#5:  Whey is one of the Most Researched Muscle-Building Supplements on the Market

muscular man holding water bottle

It’s no secret that whey protein is one of the most studied supplements in the history of nutritional supplementation. All you need to do is search “whey protein research studies” on Google and you’ll find a plethora of information that will reinforce all the points we’ve covered in this article. alone has a resource page on their website outlining more than 258 unique references to scientific papers and studies on whey protein.

With so many supplement companies vying for your attention and your money in this day and age, it’s important to do your research and make sure you understand what certain supplements do and how they can help you achieve your muscle-building goals. Part of doing your “due-diligence” also includes learning the correct way to read labels. It’s very easy for supplement companies to pull the wool over your eyes when it comes to ingredients, so arming yourself with knowledge about labels can save you a lot of time, money and health problems down the road.

The Importance of Reading the Protein Supplement Label

To be sure that you’re getting the exact amount of protein and ingredients listed on a particular supplement label, it’s wise to do some research beforehand. Even though whey is far and above one of the best supplements for muscle building, all whey protein supplements are not created equal.

As a general rule, the shorter the ingredient list and the easier those ingredients are to pronounce, the better the product is. A lot of supplement companies use fillers and other ingredients that can make a product appear like it contains 100% protein when in reality it’s not doing anything beneficial for your performance or your body. When it comes to protein supplementation, quality should always trump cost and marketing flair.

One important piece to look at is the P/Cal of a particular protein supplement. Analyzing the P/Cal of protein will tell you exactly how many calories in the supplement you are consuming come from actual protein, and how many of the calories come from fats, carbs, and fillers.

So how do you find out the P/Cal of a protein supplement? A simple math formula will tell you everything you need to know. All you do is multiply the total grams of protein by four and then divide it by the total number of calories per serving.

Let’s say a certain supplement is boasting 32 grams of protein. That seems like a great number, but if you take a closer look and notice that the supplement has 310 calories per serving, that means only 41 percent of the total calories come from protein.

So what does the other 59% of the supplement consist of? Usually, the remaining calories are empty calories that come from insulin-spiking maltodextrin or other fillers. In most cases, supplement companies don’t even divulge the added fillers and ingredients--they just list them under the category “flavorings”.

Even though a particular supplement may have fewer grams of protein “per scoop”, pay close attention to the P/Cal. If one protein supplement has a P/Cal of 41 percent and another has a P/Cal of 90 percent, it should be clear which one is best. Usually, it’s best to find a supplement that has a P/Cal of 80%+.


Try 100% Grass-Fed Whey Isolate Protein Powder

grass fed protein isolate

If you’re ready to improve your workout performance and build more muscle, we encourage you to try our 100% grass-fed whey isolate protein powder. If you don’t believe in the power of Transparent Labs protein, check out some of our online reviews. We are confident that you won’t find a better protein product on the market. Check out our product label--we care about providing you with the highest quality protein on the market.

If you have questions, contact us today!

It’s time to get your gains on!


Trevor Hiltbrand
Trevor Hiltbrand


Trevor Hiltbrand is one of the owners/co-founders of Transparent Labs and head of content creation. He got his start with supplement research back in 2013 when he began researching cognitive enhancement. With the help of the Transparent Labs Expert Panel and Advisory Board, we aim to bring our evidence based nutrition and exercise research to the world.

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