Best Whey Isolate Protein Powders of 2025, Tested and Picked by Experts

Why We Like It

After rigorous testing from our athletes and registered dietitians, Transparent Labs Whey Protein Isolate earned the highest overall score of all the whey isolates we considered, with a comprehensive score of 4.5 out of 5. If you’re looking for the best protein whey isolate, you likely want a product with little to no fat or carbs. This whey protein isolate is not only low in both fat and carbs, but it’s also made with all-natural ingredients and 100% grass-fed protein. “I love that Transparent Labs Whey Protein Isolate is free from artificial sweeteners, food dyes, and preservatives. You get 28 grams of high-quality protein without any unnecessary fluff,” adds Chelsea Rae Bourgeois, M.S., RDN, LD.

We’re big fans of this protein from Transparent Labs, giving it a 5 out of 5 for formulation. This one packs one of the largest doses of protein of all the other products in this guide — 28 grams per serving. And, it only has up to 3 grams of carbs and 2.5 grams of fat (depending on flavor). Sadly, this doesn’t have any digestive enzymes or probiotics, which might have been helpful if you have digestive issues with protein. 

It also has added electrolytes like calcium and potassium, which are important for hydration and muscle function. We also gave the flavor an overall 5 out of 5. Granted, our tester, a certified personal trainer, did try the seasonal Peppermint Hot Chocolate flavor but, “It tasted exactly like that. All I needed was some whipped cream and a mug.”

Regardless of the flavor you choose, you’ll be pleased with the solubility. Our tester had “no issues” mixing this powder with water in their best shaker bottle. There were zero clumps or floaties at all. “It’s super smooth, and even though it tastes like hot chocolate, I didn’t get any bloating or upset stomach that sometimes comes with sweet protein powders.”

This powder is on the more expensive side, earning a 3.5 out of 5 for price per serving. While TL now offers this dietary supplement in 55-serving containers, costs still begin at roughly $1.82 per serving. However, given this one has zero artificial sugars and contains a high protein content, we think it’s worth the cost (if it’s in your budget). If you still need to save some cash, NOW Sports Whey Protein Isolate instead.

Good for: Athletes who want to avoid artificial sweeteners, dyes, or preservatives in their whey isolates.

Why We Like It

Shopping on Amazon has its advantages, whether it’s the free shipping you get as a Prime member or the fact that sales pop up frequently. Sports Research Whey Protein Isolate, for example, is often on sale via the online retailer, which is a bonus since it’s already one of the more affordable whey isolates we’ve tested. It’s also a quality supp, with BarBend expert reviewer Chelsea Rae Bourgeois scoring its formulation a 4.5 out of 5.

“This is a pretty impressive whey protein powder — just take a look at its amino acid profile,” she says. “It contains 25 grams of protein per serving, including 6.9 grams of BCAAs, but minimal carbs and fat. If you’re looking to increase your protein intake without skewing your other macros, this could be a great option.”

Our tester agrees after trying out the Creamy Vanilla flavor. “Definitely got the vanilla flavor right with this protein and it does have a creamier aspect to it, whether it was taken in water or milk,” they note. “I would rate this as a very good-tasting protein powder. It mixes great in a shaker cup — not chunky at all and smooth to drink.” Taste and solubility both score a 5 out of 5 in their respective categories.

As Bourgeois notes, though, Sports Research’s basic Dutch Chocolate and Creamy Vanilla options may be a deterrent for those who desire variety in the taste department. “If you’re prone to flavor fatigue, you might get bored with Sports Research Whey Protein Isolate,” she says. Instead, you might enjoy Jacked Factory Authentic Iso.

The formulation also contains tree nuts, a common allergen, and sucralose, an artificial sweetener, so those with restrictive diets or an aversion to artificial ingredients will want to steer clear.

That said, it is Informed Sport-certified, meaning you can rest assured that it’s free of banned substances and that what you see on the label is what you get in every scoop. Bourgeois concludes, “Sports Research Whey Protein Isolate can be an excellent way to bridge the gaps between protein needs and dietary intake.” (3)

Good for: Flavor minimalists who value convenience when shopping.

Why We Like It

A protein powder can be rendered useless if it doesn’t taste good — there’s a reason we have a dedicated list to the best tasting protein powders, after all. Because of its excellent solubility and unique flavors, Jacked Factory Authentic Iso fits that description when focusing on this specific form of whey protein. We give this Authentic Iso from Jacked Factory a 4 out of 5 for solubility, finding zero clumps, grittiness, or residue in our shakes post-blending. 

As for flavor, the company offers a pretty wide range of flavors, which we appreciate. Our tester tried the limited-release Fruity Cereal Splash flavor and was pleased, giving it a 4 out of 5. “This flavor actually tasted like Froot Loops!” they exclaimed. However, it did have a bit of an odd aftertaste—not enough for our tester to dislike it, but worth knowing. It’s likely due to the use of sucralose, an artificial sweetener. 

Overall, we gave the formulation a 5 out of 5, as it’s pretty lean (only 120 calories per serving) and most of the calories come from protein (up to 27 grams of protein per serving). However, we don’t love that Jacked Factory is sweetened with sucralose, because artificial sugars can cause GI distress for some people.

Still, the extra filtration seemed to help one of our testers, who reports: “I usually hate whey protein (sorry!). So, I was really surprised that I liked this so much. Toss it in with milk and some ice, and it was an awesome vanilla milkshake. Not chalky or overly sweet, at all.”

Additionally, “Some flavors provide up to 300 milligrams of sodium, which is a significant portion of your recommended daily intake. If you’re watching your sodium intake for any reason, you might not be keen on this protein powder,” says Chelsea Rae Bourgeois, M.S., RDN, LD. Instead, you might consider NOW Sports Nutrition’s Whey Protein Isolate, which has a lower sodium content than most protein powders.

The price per serving is relatively affordable at $1.33 per scoop, earning a 4 out of 5 in this category. Still, you can find whey isolates at an even lower price point if you’re shopping on a budget.

Good for: Flavor seekers who enjoy fun, nostalgic flavors with smooth, clump-free shakes.

Why We Like It

Legion’s Whey+ supplement is one of the best clean protein powders in general, making it a clear pick for this “natural” moniker amongst the best whey protein isolates. The formulation contains zero artificial flavors or, as the brand states, “unnecessary junk,” and is a 100% all-natural formula made with whey protein that’s derived from grass-fed and pasture-raised cows.

This whey protein contains no banned substances and is third-party lab tested by Labdoor. The formula is also quite lean at only 120 calories per serving, including up to 6 grams of fat, up to 3 grams of carbs, and up to 23 grams of protein, depending on the flavor. We give this high-quality formula a 5 out of 5 rating, but if you want even fewer carbs and fats per serving, we suggest Transparent Labs Whey Protein Isolate.

Our product tester also loves the flavor and, considering there are 22 flavors to choose from, settling on one may be difficult. “I tried the Cinnamon Cereal and it tasted just like I was eating the real thing,” they note, giving the flavor a 4.5 out of 5. “I wish it were a little bit richer, but it still tasted so accurate.”

Chelsea Rae Bourgeois, M.S., RDN, LD adds, “I like the variety offered, and I love that you get more than 20 grams of protein per scoop without all the artificial junk.”

We also had zero problems with solubility, which we consider a big priority. Our tester scores this formula at 5 out of 5 in this category because they noticed zero clumps on the bottom of their shaker bottle and didn’t have to use an actual blender to get the formula to dissolve properly.

One downside? We don’t love their website design, which, we know, doesn’t actually have to do with the product, but it is part of the customer experience. “They have good customer service and great return policies,” our tester said, giving customer service a 4.5 out of 5. “But their website can get frustrating because I get a ton of pop-ups all the time. Just let me buy my protein!”

Good for: Label-conscious shoppers avoiding artificial ingredients in favor of an all-natural formula.

Why We Like It

When it comes to whey protein, the milk quality is a huge factor. After all, whey is a milk byproduct unlike plant-based protein sources used in the best vegan protein powders. Onnit uses milk from grass-fed and pasture-raised cows, so you’re getting a product that’s free of antibiotics and hormones. 

Onnit puts a high priority on quality, which our tester loves. However, we did have to dock them a little bit since the actual protein content is a little lower than other whey isolates. This powder has 20 grams per serving, whereas most others have between 25 grams to 28 grams. However, Chelsea Rae Bourgeois, M.S., RDN, LD, does appreciate the inclusion of an enzyme blend in the ingredients, which can help promote good, fast digestion. “The macro counts can be fine for certain fitness goals, and I’m intrigued by the enzyme blend,” she states in reference to her 4.5-out-of-5 formulation rating.

Our tester, a certified personal trainer, enjoys the flavor, too, but wasn’t the biggest fan of the consistency, rating this Onnit protein at 3.75 out of 5 for taste. “I tried the Mexican Chocolate, and it was good but I wasn’t as pleased with the texture,” they state. “It was very thin when you mix it with water, which is how most people drink their protein. The actual flavor did stand out compared to other chocolate proteins, though.” Another great taste-forward option is the Jacked Factory Authentic Iso.

And if you like your grass-fed protein with vegan milk, rest assured: our tester sings its praises with oat milk, too. “It’s super creamy when you mix it with oat milk, same as whole milk.”

Despite the thin texture, Onnit’s protein earns a 5 out of 5 for solubility. “This powder dissolved almost too well,” our tester adds. “I didn’t have any clumps in my shaker cup but still, it was a little too thin for my liking.” For a bit of added thickness, our tester recommends mixing with your milk of choice.

Good for: Athletes who want a little boost in digestion, thanks to the added enzyme blend.

Why We Like It

Momentous Whey Protein Isolate is a great formula for those wanting the best protein powder for muscle gain. Each serving packs up to 23.4 grams of protein, with up to 3 grams of carbs, and up to 1.5 grams of fat, making it a lean, protein-focused supplement.

“I love love love that they link up-to-date research that backs their product’s ingredients. And the use of Prohydrolase makes this product stand out,” says Chelsea Rae Bourgeois, M.S., RDN, LD, who rates the formulation at 4.25 out of 5. The research shows that Prohydrolase can increase amino acid concentrations in the post workout setting. Hello muscle gain.”

We also like that this supplement is made with milk from grass-fed cows that have no hormones or steroids. It’s also third-party tested by Informed Choice and Informed Sport, so you’re getting exactly what you read on the label.

After mixing the chocolate flavor with water, our tester, a certified personal trainer, thought it tasted quite a bit like hot cocoa. “I liked the taste and I’d drink this one again,” they said, giving a 4 out of 5 score for flavor. “I mixed it with ice cold water, and it was really smooth and easy to sip. No grittiness.” As such, we give Momentous Whey Protein Isolate a 5 out of 5 for solubility, too.

While we do enjoy this formula, the price is a tough pill to swallow. At roughly $2.20 per serving, we had to give Momentous a 1 out of 5 for price per serving, considering it’s among the highest on this list and may not be accessible to those on a stricter supplement budget. 

One 25-serving container costs $54.95, but you can find plenty of high-quality whey isolates for well under $2 per serving (like Transparent Labs Whey Isolate). Thankfully, though, Momentous does offer a “Subscribe & Save” service that offers a 10% discount when you sign up for repeat deliveries.

Good for: Lifters focused on maxing out protein post-workout.

Why We Like It

Whey isolate protein powders come with some pretty enticing benefits, but are you willing to go for these perks if it means your stomach will be torn up for hours post-consumption, causing your digestive enzymes to work overtime? Klean Isolate from Klean Athlete takes away those fears with a formulation that’s easy to drink and easy to digest. 

We attribute this stomach-friendly makeup to Klean Isolate’s impressive formulation, which we score at 4 out of 5. In each serving, you get 20 grams of protein, just 1 gram of carbohydrates, and 0 grams of fat. In addition, there’s a full amino acid profile, which can help ignite protein synthesis for better recovery, digestion, and muscle growth. (4) However, Chelsea Rae Bourgeois, registered dietitian nutritionist and our expert reviewer, states, “I just wish there were higher protein counts per serving. Yes, 20 grams is a nice protein boost, but it’s certainly not the most protein-dense option on the market.” As an alternative, Momentous Grass Fed Whey Protein Isolate has around 23g of protein per serving and digestive enzymes.

Klean Isolate also contains sunflower lecithin to help with mixability, which lent itself to our 5 out of 5 solubility score. “I really liked that this unflavored powder could be mixed with virtually any beverage of my liking,” notes our tester, a former Olympian. “I could easily add this to any concoction for a quick hit of protein throughout the day, giving it plenty of versatility, too, when it came to hitting my daily macros.”

As the name suggests, Klean Athlete Klean Isolate is also a top pick for athletes, thanks to its NSF-Certified for Sport regulation. We rate the third-party testing at 5 out of 5, as this means the formulation is free of banned substances and unwanted ingredients, making it a great pick for those that need to abide by specific governing agencies like the International Weightlifting Federation, NCAA, and others.

Good for: Competitive athletes with sensitive stomachs.

Why We Like It

OK, so you know that whey isolates can help you build muscle alongside training, but did you realize they can be vital tools for muscle recovery, as well? MyProtein’s Whey Isolate formula consists of nearly all protein, so your body can focus on repairing damaged muscle fibers after you’ve returned from the gym. (5) 

Chelsea Rae Bourgeois, registered dietitian nutritionist, rates the formulation at 4 out of 5, stating, “I appreciate how lean this macronutrient profile is, which makes it easy to account for when figuring out how to count your macros for the day.” However, Bourgeois does state that the listed micronutrients are lacking when compared to other protein powders on the market. “If you’re having trouble meeting your vitamin and mineral needs, this protein powder isn’t going to contribute much,” she adds.

This protein comes in 17 unique flavors, like Birthday Cake, Southern Comfort Southern Milkshake, and Matcha, among others. Our tester, a certified personal trainer, tried the Cookies & Cream variety and was pretty satisfied, giving it a 4 out of 5 for flavor. “I have no issues with how it tasted, and I actually really enjoyed the flavor,” they note. “It tasted a little more like cookies than cream — it even had cookie chunks in the powder.”

The company does use sucralose as a sweetener, though, so if you’re sensitive to artificial sugars, you may want to opt for a different product, like Transparent Labs Whey Isolate.

We had no issues with solubility of this product, giving it a 5 out of 5. The powder dissolved really smoothly in a shaker cup with no clumps or grittiness. “The protein doesn’t clump at all but the flavor I tried had cookie pieces in the formula,” our tester states. “So, some flavors may have little additions like that, which I don’t mind.”

You can find MyProtein Impact Whey Isolate in containers up to 11 pounds with costs per serving starting at roughly $1.69. Plus, this powder is third-party tested by Informed Choice and Informed Protein, giving you peace of mind that this whey isolate is free of any banned substances.

Good for: Recovery-minded lifters seeking a formula that’s high in protein, low in fat, and low in carbs.

Why We Like It

You don’t need to spend tons of money to get a high-quality whey isolate to help promote muscle gain and recovery. NOW Sports Nutrition’s Whey Protein Isolate is among the most budget-friendly and one of the best protein powders on Amazon, earning a 5-out-of-5 rating for value. Not only do you get a hearty amount of protein (25 grams) per serving, but you can purchase this powder in bulk for a price per serving starting at $1.23.

In terms of the formulation, we rate this NOW Sports offering at 4.25 out of 5. One serving is only 110 calories with 2 or fewer grams of carbs, up to 0.5 grams of fat, and 25 grams of protein. “It’s low in carbs and fat, so it won’t skew your macro count when you’re just trying to increase your protein intake. Plus, its sodium content is low compared to many other protein powders,” says Chelsea Rae Bourgeois, M.S., RDN, LD.

Unfortunately, NOW Sports doesn’t offer a ton of flavor options. You can choose from Creamy Chocolate, Vanilla, and Unflavored. “I tested the Unflavored version and it was pretty much what I expected. There’s a noticeable whey taste,” says our tester, a certified personal trainer, giving it a 4 out of 5. “It wasn’t bad at all, but I’d definitely recommend mixing it in a smoothie.” If you prefer tons of flavor options to choose from, try the Jacked Factory Authentic Iso.

You can also use it to make your regular old cold brew a bit more bougie, our tester adds. “I used it with cold brew coffee, and it gave it a great boost. I’ve tried a ton of chocolate protein powders, and I have to say that this one was absolutely delicious. The Creamy Chocolate makes a nice mocha with my cold brew — very complementary.”

We did give this product a 5 out of 5 for solubility, as well. “It mixed just like you’d hope,” our tester said of their blending experience. “The drink was smooth, and I didn’t notice any chalky taste or clumping.”

Good for: Budget-conscious shoppers who appreciate the combination of 25g of protein per serving at a $1.23 per serving price.