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Isopure Protein Review: Top Choice for Quality Shakes?

Scooping the vanilla Isopure flavor into my shaker bottle

Isopure Protein Review


Testing Criteria
Taste 7.75 Mixability 8.2 Digestibility 10 Protein Density 10 Cost 7.5 Nutritional Value 7.8 Brand Reputation 7.5


  • Delivers 25 grams of protein per serving with 1 gram or less of carbs (depending on which flavor you choose)
  • Rich in BCAAs and L-Glutamine, aiding muscle growth and recovery.
  • Offers a blend of vitamins and minerals for a balanced diet.
  • Mixes smoothly, and goes down easy.


  • Contains soy
  • Does not third party test

Our Verdict

Isopure whey protein isolate is great if you’re on a low-carb or ketogenic diet, with nearly 100% of its calories coming from protein, and willing to pay a premium price.

If you’re on a tight budget or looking for a more caloric, meal-replacement like protein powder, you should keep looking. But overall, this is a product I stand behind, and one I use as a regular part of my training regimen.

Protein Content 25g Calories 100 Carbs 0g Protein Density 100% Sugar 0g Fat 0g Sodium 240mg Sweeteners Sucralose Allergens Milk, Soy
Verified reviews by
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In this Review
Overview | Taste | Digestibility | Protein Density | Cost | Nutritional Value | Mixability | Third Party Testing | Brand Reputation | Comparisons | Bottom Line

If you prefer to watch than read, check out my video review on YouTube:

A Quick Look at Isopure’s Whey Protein Isolate

Isopure has been a popular choice since 1984 for its high protein and clean ingredients.

Their whey protein isolate powder contains 25g of protein per scoop. The vanilla flavor has zero fat, carbs and sugar. The chocolate flavor has just 1g carbs while keeping calories and fat low.

With a focus on simple, pure ingredients, Isopure has developed a strong reputation among protein users over the past several decades.

Low Carb vs Zero Carb Options

Isopure offers 10+ flavors across a variety of low and no carb options, each with a slightly different ingredient profile:

Per serving Zero Carb (Flavored) Zero Carb (Unflavored) Low Carb (Natural Flavor)
Protein (g) 25g 25g 25g
Calories (kcal) 100 100 120
Carbs 0g 0g 4g
Calories from protein (%) 100% 100% 83%
Sugar 0g 0g 3g
Fat 0g 0g 0g
Sodium 240mg 160mg 240mg
Sweeteners Sucralose (artificial) None Monk fruit (natural)
Allergens Soy Soy Soy

*Note: the zero carb flavor is Creamy vanilla, and the natural flavor is Vanilla.

Key takeaways:

  • The unflavored and natural flavor options do not contain artificial sweeteners.
  • The natural flavor contains monk fruit — a natural sweetener — and has more calories and carbs per serving.
  • All options contain soy.

My Experience With Isopure Whey Protein

Taste Test (7.75)

I tested the vanilla and chocolate flavors. Vanilla is simple yet satisfying. I gave it an 8 out of 10, especially considering there are no carbs, sugars, or fats.

Chocolate has a little bit more personality with a hint of carbs and fat. But it falls short on that rich, indulgent flavor we chocolate lovers crave. So it gets a 7.6 from me.

Both flavors have the Isopure signature clean and pure taste. Overall, this protein that doesn’t just pass the taste test in my books; it sets the bar.

Scooping the vanilla Isopure flavor into my shaker bottle

Mixing the vanilla flavor

Drinking the chocolate Isopure

Tasting the chocolate Isopure

Digestibility (10)

Isopure’s whey protein isolate is light and easy to digest. It’s stripped down, leaving only what you need, which makes it easier to absorb aiding in recovery and muscle building without the digestive drama.

If you have a sensitive stomach or are lactose intolerant, even an isolate can cause issues. While Isopure is generally easier on the stomach due to its purity, it’s not a free pass for everyone. It’s low in lactose, sure, but it’s not lactose-free.

Remember, you’re paying for this digestibility and quality. If your budget’s tight and your stomach’s made of steel, you may prefer a cheaper, less refined protein. But if you have a sensitive system, and are willing to pay a premium, Isopure is a solid pick.

Protein density (10)

This is where Isopure Whey Isolate shines.

Nearly 100% of the calories you get from this powder are from protein. Some of the flavored options do contain a gram or less of fat and carbs, but it’s not much. None of the zero carb flavors contain sugar.

The natural flavor option is 83% dense with protein, and does contain a few grams of carbs and sugar.

If you’re looking to stay lean, following a keto diet, or just like to eat clean, Isopure is a fantastic option.

Isopure protein full scoops in kitchen

Chocolate vs vanilla

Cost (7.5)

Per serving Zero Carb (Flavored) Zero Carb (Unflavored) Low Carb (Natural Flavor)
Serving size (g) 31g 29g 34g
Price per serving $2.13 $2.12 $2.00
Price per gram of protein (g) $0.08 $0.08 $0.08

All of the Isopure whey protein options cost around $2 per serving and $0.08 per gram of protein.

The natural flavor serving size is slightly larger at 34g per serving, which is why the price per serving figure is a bit lower.

Note: the price will vary depending on the size of the tub and the retailer you buy it from. The above prices are from the Isopure website.

Nutritional value (7.8)

Isopure is a clean protein powder. Each serving contains 25 grams of protein with only 100 to 110 calories making it one of the leanest protein powders on the market.

Some of the (non-natural) flavors do contain artificial flavoring, however, which is why I can’t give it 10s across the board. But most protein powders on the market contain artificial ingredients, so it’s not just Isopure.

Overall, I stand behind Isopure’s ingredient profile. It’s clean, pure, and calorically dense in the best of ways.

Chocolate Isopure protein ingredients label

Close up of the chocolate ingredients

Mixability (8.2)

Isopure protein powder mixes seamlessly, giving you a smooth, easy-to-drink shake every time. Just a quick stir or shake, and you’re good to go.

It easily dissolves in water, making it perfect for those busy days when you need a quick protein fix without the clumps. If you’ve struggled with mixability in the past, look no further.

Note: I tested its mixability in 8oz of water, and shook for 20-30 seconds with a shaker bottle and ball.

After shaking the Chocolate Isopure

After mixing the chocolate flavor

Third party testing (0)

Isopure doesn’t third party test so I had to give it a 0. They do, however, have a great reputation in the market, reflected through thousands of positive online reviews on platforms like Amazon.

If third-party testing is a non-negotiable for you, Isopure is not the right protein for you.

Brand reputation (7.5)

The Isopure brand is trustworthy in my books. They have been in the supplement business for more than 30 years, and have managed to maintain a positive reputation with consumers the entire time.

Their website is active and easy to find, as is their contact information. And they’ve not been involved in any major controversies since inception in the 1980s.

Isopure Whey Protein Vs The Market

Protein Price per serving ($) Price per gram of protein (g) Protein density (%) Calories per serving (kcal)
Isopure Low Carb (Flavored) $2.13 $0.08 ~100% 100-110
Optimum Gold Standard $1.56 $0.06 74% 130
Dymatize ISO 100 $1.24 $0.05 83% 120
Muscle Milk Genuine Whey $1.77 $0.06 46% 280
Ghost Whey Protein $1.65 $0.07 67% 150

Compared to other popular whey proteins on the market:

  • Isopure is the most expensive at around $2 per serving and $0.08 per gram of protein
  • Isopure is the leanest option with nearly 100% of its calories coming from protein (again, depending on the flavor)
  • Isopure has the fewest calories per serving

Bottom Line

If you’re watching your calories and carbs, or value simple ingredients, Isopure is a great choice. The ingredient profile is one of the cleanest on the market.

Conversely, if you’re on a budget or have dietary restrictions like lactose intolerance or allergies to soy or artificial sweeteners, Isopure may not be for you

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