Our Whey Protein Testing Methodology

Whey protein is the most common and widely used form of protein in dietary supplements. That’s because it’s one of the highest quality forms of complete proteins available, and is also backed by dozens of clinical trials. But there is more than one type of whey protein available, and each type has its own benefits and applications.

With so many whey protein powder formulas available, we knew that finding the absolute best ones would involve more than just sorting out the good from the bad. There are a lot of high quality whey protein supplements on the market, so to determine which ones stand above the rest, we developed an in-depth whey protein testing methodology and scoring algorithm.

We score across five primary categories: protein source, macronutrient calories per serving, protein per serving, price per gram of protein and sweeteners. Products can also earn bonus credits that boost the overall rating. These categories were developed in collaboration with registered dietitian and doctor of exercise physiology Chris Mohr.

How We Score Whey Protein Powder

Our whey protein powder scoring methodology branches off of our broader nutrition product and supplement methodology. We assign each product a score of 1 out of 5 for each of the categories we test in. Those scores are then weighted based on importance and averaged to produce a cumulative score out of 5 for each product, with 1 being the lowest rating and 5 being highest.

Criteria We Evaluate

Protein source

The primary source of protein in a whey protein powder formula determines how easily it’s digested and absorbed in the body, as well as how many calories come from protein versus carbohydrates or fats. We evaluate four whey protein sources: whey concentrate, whey isolate, whey hydrolysate and whey protein blends.

Whey concentrate is a form of whey protein that includes slightly more carbohydrates (from lactose) and fat than the other forms of whey. This means, gram for gram, it's not going to provide quite the same amount of protein as whey isolate and hydrolysate. Also, the lactose sugars can impact digestion for those with a lactose intolerance. While still an excellent source of protein, whey concentrate is given the lowest marks, since it’s the least pure form of protein and may cause digestive problems for some people.
Whey isolate is, as the name implies, a more isolated form of protein than a concentrate. The carbohydrates and fat are removed through a filtration process to provide a more protein-rich product that's usually easier to digest for those with lactose intolerance. As such, it earns higher marks than whey concentrate.
Whey hydrolysate is essentially pre-digested, in the sense that it might be more rapidly absorbed. In one 2010 study in the Journal of Science and Medicine in Sport, researchers compared equal amounts of whey isolate and hydrolysate and found slightly greater outcomes in those using the hydrolysate product. For these reasons, whey hydrolysate earns the highest marks in this category.
Whey blends combine two or more forms of whey protein. They usually combine whey concentrate with whey isolate or hydrolysate. Since they have a mix of protein sources, they receive a similar score to formulas with whey isolate.

Macronutrient calories per serving

Ideally, the bulk of the calories consumed through whey protein powder will come from the protein. However, depending on the protein source and other ingredients, calories can also come from carbohydrates and fats.

Carbohydrates can be used for energy and flavor, but since the carbohydrates added to protein powders are typically sugar-based carbs, it's best to leave them out most of the time. Whey protein formulas with a high source of calories from carbs earn the lowest marks in our rating system.
Fat can be a great addition to a protein shake because it may help slow the absorption of the ingredients, making the satiating effect of protein last longer. It may also improve the flavor, texture and mouthfeel of the product. Whey formulas with a high percentage of calories from fat earn a higher score than carbs in this category, but less than protein.
Protein consumption is the goal of using a whey protein powder, so clearly this is the focus and key macronutrient. With that in mind, we evaluate the percentage of calories that come from protein versus carbs or fats and award the highest marks to formulas with the highest ratio of calories from protein.

Total protein per serving

Most data suggests aiming for 25-30 grams of protein at a time. Daily protein needs vary by individual, but based on this data, 25-30 grams is optimal per serving of whey protein powder. Most whey protein supplements contain 15-30 grams of protein per serving. Here’s how we score them based on protein content:

19 grams or less per serving: This amount receives the lowest marks. Not only is it below the 25-gram recommended amount, but it’s also generally not a good value.
20-25 grams per serving: This dose earns average marks because it reaches the optimal range of protein per serving, but only the lower end of that range.
26+ grams per serving: With the data suggesting the benefits (not to mention value) of higher protein per serving, this amount aligns with the research supported benefits and receives the highest marks.

Price per gram of protein

Price is an important factor for consumers, and often (though not always) reflects the quality of a product. There are high quality whey proteins that cost below average, and relatively low quality whey protein products that cost more than average. Because of this potential discrepancy, this category receives less weight in the overall score.

Since we deem protein content to be the best measure of value for a whey protein powder product, we rate each protein powder based on the price per gram of protein. Here’s the breakdown:

$0.03-$0.05 per gram: The highest marks are given to the most affordable whey protein powders.
$0.06-$0.08 per gram: This is still a relatively low cost when compared to food sources of protein, but edging slightly higher for those who use protein powders on the regular. This range earns average marks.
$0.09+ per gram: If price is a barrier, then higher than $0.09 per gram is more costly compared to some other options, which could be a challenge for many consumers. For that reason, whey protein powders costing $0.09 or more per gram of protein receive the lowest marks.

Sweeteners

Sweeteners may improve the taste profile of a whey protein powder, but they don’t add nutritional value beyond sometimes being a fast-burning energy source. We prefer to see minimal sweeteners in whey protein formulas, and we prefer some over others. Here's how we rate each sweetener:

Sugar: Added sugar is a refined carbohydrate, and an ingredient most Americans over-consume. The Centers for Disease Control and Prevention (CDC) recommends limiting added sugar to no more than 10 percent of your daily calories. For a daily 2,000-calorie diet, that means no more than 200 calories per day should come from sugar (approximately 12 teaspoons). Based on research from the U.S. Department of Agriculture, adult men consumed an average of 17 teaspoons of sugar per day, and women consumed 15 teaspoons per day from 2017-2018. To avoid health issues like obesity, type 2 diabetes and heart disease, people should limit their added sugar intake. While there often isn't much added sugar in protein supplements, limiting it as an ingredient is wise, which is why whey protein formulas with refined sugar receive the lowest marks.
Honey: Honey is a form of added sugar. While it's a different form of added sugar, it’s still sugar, and physiologically there are few differences between the two—none of which have clinical significance. For this reason, we rate honey the same as refined sugar.
Agave: Similar to honey, agave is a form of added sugar with few differences from refined sugar and none that have clinical meaning. It receives the same low score as sugar and honey.
Maltodextrin: Maltodextrin is a carbohydrate derived from rice, corn, wheat and potato starch. Although it’s not sugar, it acts similarly in the body, so it shares the same score as all forms of sugar.
Dextrose: Dextrose is marketed as a high-quality alternative to sugar, but with a glycemic index of 100, it's no different than the other added sugars. It also receives the lowest score in this category.
Sucralose, Aspartame, Acesulfame: Artificial sweeteners like sucralose, aspartame and acesulfame are non-nutritive, non-caloric sweeteners. They have repeatedly been shown to be safe in the research at moderate amounts. Although a recent WHO report suggested "artificial sweeteners to be possible carcinogens", the dosing that could cause concern is equal to that in approximately nine to 14 cans of diet soft drinks and a much higher dosing than what might be in a protein supplement. Still, the lack of research on the long term use of artificial sweeteners is the reason we give them a low score, though slightly higher than the score for sugar.
Erythritol, Xylitol: Erythritol and xylitol are sugar alcohols that provide sweetness with very few calories. We rate them higher than sugar and artificial sweeteners because they contribute to oral health, including reducing plaque, alleviating constipation and triggering secretion of gut hormones that regulate satiety (the feeling of fullness after you eat). One potential downside is that too much of either may cause stomach ache, cramping, gas or even diarrhea, which is why they aren’t given the highest score.
Stevia: Stevia starts as a plant and is refined and concentrated to create a sweeter end product. Some consumers may be turned off by the sometimes bitter flavor of stevia, but it’s considered safe and is free of calories and sugar. We give it the highest score in this category.
Monk Fruit: Monk fruit is a non-caloric sweetener that comes from a fruit that's native to China. Its flavor can be less off-putting than stevia, so some appreciate its ability to provide sweetness without the bitter aftertaste. Like stevia, we give it the highest score in this category.

Bonus points

Since the supplement industry—especially protein supplements—is constantly evolving, we pay attention to products and brands that are going above and beyond to stand out. That’s why we incorporate bonus credits into our whey protein scores to recognize innovation and encourage healthy competition among all brands. All bonus points are equally weighted and cumulatively provide a small boost to the product's overall score.

Third-party testing

The Food & Drug Administration (FDA) doesn’t regulate dietary supplements before they’re released to the market (though they do regulate ingredients and finished products), so it’s important to look for products that have been third-party tested for purity and potency. These testing certifications show whether a dietary supplement contains what the brand says it contains in the doses advertised (potency). It also tests for harmful toxins (i.e. mold, heavy metals, etc.), and some check for banned substances (purity).

Nearly all reputable supplement companies test their products in-house for safety and label accuracy, but many brands also make the decision to have their products tested by a third party for even further quality and safety assurance. That’s why we've chosen to give brands who take on this additional responsibility bonus credits.

Smaller, newer supplement companies often can’t afford testing by high profile third-party testing labs—regardless of the purity or potency of their products—which is why third-party testing is a bonus in our scoring methodology, not a main category.

The most reputable independent testing labs include:

Informed Choice (ICFS): Informed Choice offers several certifications, the most recognizable of which being the Informed Sport badge. This certification is critical for athletes who might get drug tested for their sport.
NSF: NSF is an independent testing organization founded in 1944.
U.S. Pharmacopeia (USP): USP is an independent, non-profit scientific organization that tests medicines and supplements, founded over 200 years ago.

Enzymes for digestion

Whey protein, particularly whey concentrate, can cause gastrointestinal issues in those with a lactose intolerance. Similar to how some dairy producers are now adding the lactose enzyme to milk, enzymes are often added to whey protein supplements. They are thought to aid in digestion and absorption, though data doesn't necessarily support their addition in whey protein powders.

Sustainable packaging

Sports Illustrated Showcase has an ongoing commitment to sustainability. The supplement industry is known to contribute significantly to plastic manufacturing and waste. For example, protein containers are usually large one-, two- or five-pound tubs of plastic. Any company that offers sustainable packaging gets bonus credits because less plastic tubs end up in landfills.

100% grass-fed whey

Cows fed a diet solely of grass have been shown to produce milk that is reportedly creamier and better tasting than cows fed a conventional diet of grain. Their milk also contains more omega-3 fatty acids. Omega-3s have powerful anti-inflammatory effects, and are often underconsumed in the U.S. Studies of athletes have shown faster recovery and better performance with omega-3 consumption. Finally, we consider animal welfare a bonus. Grass-fed cows have a diet that more closely resembles what they would eat naturally, and they also live in a less crowded, less stressful environment than grain-fed cows.

Certified organic

While organic certification often comes with a higher price point, it may offer some consumers peace of mind about the products they're consuming. According to some studies, certified organic milk provides more nutrients than non-organic milk, including omega-3 and omega-6 fatty acids, vitamin E and iron. Additionally, milk from cows on organic farms contains virtually no pesticides or antibiotics. Finally, organic farming may improve soil quality and the cows’ quality of life.

No proprietary blends

Transparent labeling is the only way to know exactly what's in a product. Labeling with proprietary blends offers visibility into the ingredients included in the blend, but not the specific amounts. Transparent labels enable consumers to see whether or not the key ingredients are included in clinically meaningful doses.

Summary

There are countless whey protein formulas available for consumers, and our job at Sports Illustrated Showcase is to determine which products stand above the rest in terms of quality, potency, nutrition and value. Our whey protein testing methodology involves scoring products across five categories chosen in partnership with nutrition experts. The final weighted score supports our decision to either include or exclude individual products.

For more information on our nutrition and supplement testing philosophy, please refer to Our Nutrition Products and Supplements Methodology page.