Head to head · Protein Powder
Isopure Zero Carb Whey Protein Isolate vs Legion Whey+ Grass-Fed Whey Protein Isolate
Legion scores higher overall (8.3 vs 7.8 out of 10), mainly on quality & purity and transparency. Isopure still leads on efficacy.
Updated September 2026 from our full reviews · How we score
A true zero-carb whey isolate: 25 g of protein plus a broad vitamin and mineral blend in a 110-calorie scoop, at a price above most rivals.
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A naturally sweetened whey isolate from Truly Grass Fed-certified Irish milk, with Labdoor certification and batch lab reports linked online.
We may earn a commission when you buy through these links — it never affects our scores. How we make money
We may earn a commission when you buy through these links — it never affects our scores. How we make money
The short answer
Choose Isopure if…
- Keto and strict low-carb diets
- People who want added vitamins and minerals
- Those who prefer a less-sweet vanilla
- You care most about efficacy
Choose Legion if…
- People avoiding artificial sweeteners and dyes
- Shoppers who want verified grass-fed sourcing
- Buyers who like checking lab reports
- You care most about quality & purity, transparency
Side by side
| Zero Carb Whey Protein Isolate | Whey+ Grass-Fed Whey Protein Isolate | |
|---|---|---|
| Our score | 7.8 / 10 | 8.3 / 10 |
| Efficacy (30%) | 8.9 | 8.4 |
| Quality & Purity (25%) | 7.4 | 8.9 |
| Value (20%) | 6.8 | 7.0 |
| Experience (15%) | 7.8 | 8.0 |
| Transparency (10%) | 7.8 | 9.2 |
| Form | Powder | Powder |
| Serving | 1 scoop (31 g)40 servings per container | 1 scoop (26 g, Dutch Chocolate)30 servings per container |
| Testing & certifications | cGMP facility | NSF Contents CertifiedThird-party testedNon-GMO Project Verified |
| Dietary | Gluten-free, Sugar-free, Keto-friendly | Gluten-free, Non-GMO, Sugar-free |
| Key ingredients |
|
|
| Flavors | 6 (Creamy Vanilla, Cookies & Cream, Strawberries & Cream…) | 8 (Dutch Chocolate, French Vanilla, Cinnamon Cereal…) |
| Creator video reviews | 4 | 5 |
Pros and cons
Zero Carb Whey Protein Isolate
- 25 g of protein with 0 g carbs and 0 g sugar per 110-calorie scoop
- All of the protein comes from whey protein isolate
- Broad vitamin and mineral blend, including 100% of the Daily Value for vitamin B12
- Large review base on Amazon (4.6 stars from more than 13,000 ratings)
- No third-party banned-substance certification found; testing is done in-house
- About $2.24 per serving for the 40-serving tub, and more on the brand site
- Contains soy lecithin, sucralose, artificial flavor and xanthan gum
- Flavor and texture draw mixed feedback, with some reviewers calling it gritty or bland
Whey+ Grass-Fed Whey Protein Isolate
- Whey isolate certified under the Truly Grass Fed program
- NSF contents-certified (Dutch Chocolate and French Vanilla) and Labdoor-certified, with certificates of analysis linked online
- No artificial sweeteners or dyes, and no added sugar
- buyers often mention smooth mixing and easy digestion
- 21 to 23 g of protein per scoop, a little below leading isolates
- About $2.06 per serving, with a higher list price on the brand site
- Stevia is noticeable to some reviewers
- Not in the NSF Certified for Sport or Informed Choice programs, and the Amazon listing states it contains milk and soy
Our verdicts
Zero Carb Whey Protein Isolate
Isopure Zero Carb does exactly what the name promises: 25 g of isolate protein with no carbs or sugar, plus a vitamin and mineral boost. It is a sensible pick for strict low-carb and keto eaters, but the lack of third-party certification, the artificial sweetener and a price well above rivals such as ISO100 keep it out of the top tier.
Full review
Whey+ Grass-Fed Whey Protein Isolate
Legion Whey+ is one of the most credible naturally sweetened whey isolates, pairing certified grass-fed sourcing with public lab testing. You get slightly less protein per scoop than some rivals and pay a premium, but for buyers avoiding artificial sweeteners who want proof of what is in the bag, it is an easy recommendation.
Full review
What creators say
Questions people ask
Is Isopure better than Legion?
Are Isopure and Legion third-party tested?
Who should choose Isopure over Legion?
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