Whey Protein Isolate vs. Concentrate: What's The Difference & Is One Better?

While many of us have heard of whey protein, few know the differences between its two primary forms: whey protein isolate and concentrate.

In this article, protein research experts compare the benefits and potential side effects of taking whey protein isolate vs. concentrate. They also cover whether whey protein isolate or concentrate is better for muscle gain and how much to take as a beginner.

Whey protein is the remaining liquid portion of milk that separates from curds when milk is processed to produce cheese, casein, or yogurt. This watery substance contains fast-digesting, high-quality whey proteins.

Whey protein is considered a complete protein since it has all nine essential amino acids1, including the branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—for optimal muscle growth.

Whey protein isolate is made by removing fats, carbohydrates, and other nutrients from whey protein. This process creates a highly filtered form of whey protein comprised of 90 to 95% protein and less than 1% lactose2.

As detailed above, both whey protein isolate and concentrate are derived from milk protein and are byproducts of the cheese and yogurt manufacturing process. They're not suitable for vegans, who will want to look for plant-derived protein powders instead.

In addition, both whey protein isolate and concentrate are processed to remove other nutrients like fats and carbs for increased protein content.

Regardless of the form, whey protein is considered a "fast-acting" protein with an estimated absorption rate of roughly 10 grams per hour4. That means it would take only two hours on average to absorb a 20-gram serving of either whey protein isolate or concentrate.

"Both whey protein isolate and concentrate are easy to digest," says Stuart Phillips, Ph.D., professor in the Department of Kinesiology and research director of the Protein Metabolism Research Laboratory at McMaster University. While whey concentrate is slightly higher in lactose than whey isolate, it still won't cause digestive upset in most people.

The one exception is if someone is lactose intolerant, "then they may experience gas, bloating, and gastrointestinal distress with concentrate," Phillips adds. "But [they'll feel it] less than if they drank the volume of milk to get the same amount of protein."

Whether you choose isolate or concentrate, whey protein is a complete protein that contains all nine essential amino acids, making it a high-quality protein source. This is a main difference between whey protein and plant proteins, most of which are considered incomplete on their own.

This is important because humans must acquire essential amino acids5 through diet since our bodies don't produce enough.

A 2020 study published in the 6Journal of Sports Medicine and Physical Fitness6 found that whey protein isolate and concentrate had similar benefits on cardiorespiratory fitness, muscle protein synthesis (MPS), overall strength, physical performance, and fitness outcomes.

"If you take 20 to 30 grams of protein from a whey protein isolate or a whey protein concentrate, your training adaptations will be the same," states Church.

Whey protein isolate tends to be more costly since it undergoes a longer manufacturing process, resulting in higher protein content. "Generally, isolates are more expensive since they have a higher protein concentration," says Church.

As mentioned above, whey protein isolates have higher protein content than concentrate. Typically, whey protein isolate contains 90 to 95% protein, while concentrate contains 70 to 80%.

Since whey protein isolate is more processed, it contains less lactose and fewer carbohydrates and fats. As a result, whey protein isolate tends to have less than 1% lactose, making it a safer option for those with lactose intolerance.

Since whey protein concentrate is more calorically dense and contains other nutrients, it can be more filling than isolate. "Due to the higher total product needed, lactose, carbohydrate, and fat content, whey protein concentrate can be more satiating than whey protein isolates," says Church.

A 2019 meta-analysis published in 7Nutrients7 observed that whey protein concentrate has a more significant impact on fat mass reduction than other forms of whey protein, including isolate.

However, it's worth noting that the studies included in the analysis were performed on athletes and physically active individuals who likely have highly efficient metabolisms, so the results can't necessarily be applied to the general population.

So which is better, isolate or concentrate? Both are readily absorbable, easy to digest, and good for boosting physical performance. Ultimately, the answer boils down to individual needs, how they're used, and personal preferences.

If you're lactose intolerant or sensitive to dairy, consuming an isolate is a better choice since it contains less lactose.

Your health and fitness goals might also impact which one you choose. "If someone is trying to gain mass and eat in a caloric surplus, ingesting whey protein isolate might be preferred since you won't feel as full due to the lower lactose, carbohydrate, and fat content," explains Church. "Conversely, whey protein concentrate can be great for those wanting to feel fuller for longer."

There are no legal provisions for the Food & Drug Administration (FDA)8 to approve dietary supplements for safety before being sold to consumers.

Fortunately, many supplement companies follow strict third-party testing guidelines to ensure their product is safe and of the highest quality. Phillips advises, "Look for supplements with the National Sanitation Foundation (NSF) seal or Informed Sports stamp. That ensures the product was made by a well-known, reputable company."

When searching for a high-quality whey protein, choose a product that is sugar-free, contains as few extra ingredients as possible, and is sustainably sourced and packaged.

"Find a whey protein with all the essential amino acids in the required range," adds Church. "Ideally, the product should provide 20 to 30 grams of protein per serving9 with 3 grams of leucine for optimal MPS10."

Whey protein is a fast-digesting, easily absorbed dietary protein supplement. The two most common forms are whey protein and isolate. Both are beneficial for recovery and physical performance but differ in protein concentration and how they're processed. Regardless of your health and fitness goals, supplementing whey protein in its isolate or concentrate form can help you meet your daily protein needs.