Head to head · Protein Powder
Legion Whey+ Grass-Fed Whey Protein Isolate vs Optimum Nutrition Gold Standard 100% Casein
Legion scores higher overall (8.3 vs 8.1 out of 10), mainly on quality & purity and transparency. Optimum Nutrition still leads on value and experience.
Updated September 2026 from our full reviews · How we score
A naturally sweetened whey isolate from Truly Grass Fed-certified Irish milk, with Labdoor certification and batch lab reports linked online.
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A slow-digesting micellar casein with 24 g of protein per scoop for bedtime or long gaps between meals; thick, filling and fairly priced.
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 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
Choose Optimum Nutrition if…
- A slow-digesting shake before bed
- Staying full between meals
- Thick shakes and protein puddings
- You care most about value, experience
Side by side
| Whey+ Grass-Fed Whey Protein Isolate | Gold Standard 100% Casein | |
|---|---|---|
| Our score | 8.3 / 10 | 8.1 / 10 |
| Efficacy (30%) | 8.4 | 8.3 |
| Quality & Purity (25%) | 8.9 | 7.4 |
| Value (20%) | 7.0 | 8.6 |
| Experience (15%) | 8.0 | 8.5 |
| Transparency (10%) | 9.2 | 7.8 |
| Form | Powder | Powder |
| Serving | 1 scoop (26 g, Dutch Chocolate)30 servings per container | 1 scoop (34 g)53 servings per container |
| Testing & certifications | NSF Contents CertifiedThird-party testedNon-GMO Project Verified | None verified |
| Dietary | Gluten-free, Non-GMO, Sugar-free | Gluten-free |
| Key ingredients |
|
|
| Flavors | 8 (Dutch Chocolate, French Vanilla, Cinnamon Cereal…) | 4 (Chocolate Supreme, Creamy Vanilla, Chocolate Peanut Butter…) |
| Creator video reviews | 5 | 3 |
Pros and cons
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
Gold Standard 100% Casein
- 24 g of micellar casein protein per 120-calorie scoop
- Adds 500 mg of calcium and 100% of the Daily Value for zinc
- About $1.40 per serving, good value for casein
- 4.6 stars from more than 9,000 buyer ratings, with many saying it keeps them full
- Not listed among ON's Informed Choice-certified products
- Sweetened with both acesulfame potassium and sucralose, plus artificial flavor
- Thick texture and mixability get mixed reviews
- One scoop is below the 30 to 40 g used in most pre-sleep protein studies
Our verdicts
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
Gold Standard 100% Casein
Gold Standard 100% Casein is a dependable, well-priced micellar casein for nighttime or between-meal protein, with good flavor and a filling texture. It lacks the named third-party certification of ON's whey and uses artificial sweeteners, but for most people who want a slow-digesting shake it does the job at a fair price.
Full review
What creators say
Questions people ask
Is Legion better than Optimum Nutrition?
Are Legion and Optimum Nutrition third-party tested?
Who should choose Legion over Optimum Nutrition?
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