Isopure is a protein brand that's marketed as keto-friendly, and which is manufactured by a company called Glanbia Performance Nutrition. The company describes their protein powder line as "Pure & Simple," and offers low-carb and zero-carb options.
But does Isopure provide an effective protein dose for muscle building? Does it contain any unhealthy ingredients? Is regular whey protein zero-carb? And is Isopure better or worse than popular protein powders like Gold Standard Whey?
In this article we'll answer all of these questions and more, as we analyze the ingredients in two of Isopure's most popular products (Zero Carb Protein Powder and Protein Drink) to give our take on whether or not they're effectively formulated.
We'll also discuss whether regular whey protein contains carbs, compare Isopure to other popular protein brands, in terms of formulation quality, to pick our winners (and losers).
Key takeaways:
- Unflavored protein powder is effectively formulated
- Protein drink is unhealthy in our opinion
- We do not currently recommend Isopure
Ingredient Analysis — Zero Carb Protein Powder
The ingredients in Isopure Zero Carb Protein Unflavored are shown below:
This protein powder provides 25 grams (g) of protein per serving, which is an effective dose.
A 2018 medical review suggests that around 25 g of protein post-workout or more provides maximal benefit for muscle building.
Soy lecithin is an emulsifier that should be safe and non-toxic.
We generally prefer single-ingredient protein powders, as soy lecithin is a "processed" ingredient, and there is no information on the whey protein sourcing on Isopure's product page (we consider animal products sourced from pastured animals to be healthier).
The unflavored version of the Isopure protein powder is the only one we consider somewhat healthy.
The flavored versions contain a number of inactive ingredients we consider unhealthy, such as artificial flavors, artificial colors and synthetic vitamin and mineral additives.
Ingredient Analysis — Protein Drink
The ingredients in the Grape Frost flavor of Isopure Protein Drink are shown below:
Whey protein isolate is included at a 32 g dose, which is effective for muscle building.
There are a number of inactive ingredients in this formulation that we consider to be unhealthy.
Phosphoric acid is clinically shown to be associated with low blood calcium levels.
Natural and artificial flavor are categorical descriptors that fail to identify the specific flavoring chemicals.
We consider artificial flavor to be particularly unhealthy, as some artificial flavors were shown to be toxic to animal cells in a clinical trial published in the Brazilian Journal of Biology.
Sucralose is an artificial sweetener shown to cause negative changes to insulin function in healthy, young adults, as we documented in our review of another protein brand called Seeq.
Red 40 and Blue 1 are artificial food dyes, and a 2020 meta-study on artificial food dyes and health stated the following:
"Artificial dyes have neurotoxic chemicals that aggravate mental health problems."
Overall, we consider Isopure Protein Drink likely to be effective for supporting muscle growth, but we don't currently recommend this product from a health perspective due to the inactive ingredients discussed above.
Isn't Most Whey Low-Carb?
Isopure's marketing centers on its low-carb and zero-carb options, which is a somewhat strange value proposition in our opinion, given that whey protein isolate has low or zero carbs in most supplements.
Consider the Nutrition Facts label below from Nutricost Whey Protein Isolate:
This supplement provides only 1 g of carbs per serving, but also provides more protein and calories per serving.
For individuals on a ketogenic (keto) diet, perhaps it's worth paying extra for Isopure to save that 1 g of carbs per serving, but it's a substantial price premium.
Isopure Zero Carb Protein Powder currently costs $79.99 for 47 servings, or $1.70 per serving.
Nutricost Whey Protein Isolate currently costs $72.95 for 65 servings, or $1.12 per serving.
Since whey protein isolate should be functionally equivalent between brands, budget-conscious consumers may want to consider other whey protein isolate brands than Isopure.
Isopure vs. Popular Protein Brands
Here's how Isopure compares to other popular protein brands in terms of formulation quality, in our opinion:
Gold Standard Whey Protein
Contains unhealthy inactive ingredients like Yellow 5, which is clinically shown to have the capacity to damage DNA.
Isopure's protein powder is the healthier choice.
Winner: Isopure
Nurri Protein Shake
Contains two artificial sweeteners which can be harmful to human health, as we documented in our Nurri Protein Shake reviews article.
Isopure's protein powder is the healthier choice.
Winner: Isopure
Seeq
This fruit-flavored protein powder contains four inactive ingredients we consider unhealthy.
Isopure's protein powder has the advantage from a health perspective.
Winner: Isopure
Our Clean Protein Picks
MBG Whey Protein Isolate+ is our top overall protein powder.
Whey protein is a "complete" protein, meaning it contains all nine essential amino acids.
Anthony's Organic Hemp Protein is our top vegan protein pick.
It's extremely nutrient-dense, providing 25% of the Daily Value (DV) of iron and 8% of the DV of potassium.
Both of the products recommended in this section are free of ingredients that we consider to be unhealthy.
Isopure Pros and Cons
Pros:
- Zero Carb Protein Powder has no unhealthy ingredients
- Zero Carb Protein Powder is only keto protein powder we've come across
- Both products reviewed have effective protein dose for muscle building
- Healthier than competitors
Cons:
- Protein Drink contains artificial flavors
- Protein Drink contains artificial colors
- Protein Drink contains an artificial sweetener
- Doesn't appear to be clinically tested
- Unclear if brand sources from grass-fed animals
