Head to head · Protein Powder
Dymatize ISO100 Hydrolyzed Whey Protein Isolate vs Optimum Nutrition Gold Standard 100% Casein
Dymatize scores higher overall (8.7 vs 8.1 out of 10), mainly on efficacy, quality & purity, experience and transparency. Optimum Nutrition still leads on value.
Updated September 2026 from our full reviews · How we score
An all-isolate whey with a hydrolyzed fraction: 25 g protein and about 2.7 g leucine per 120-calorie scoop, with Informed Choice testing.
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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 Dymatize if…
- Lifters who want a low-carb, low-fat isolate
- People with mild lactose sensitivity
- Drug-tested athletes
- Calorie-conscious dieters
- You care most about efficacy, quality & purity, experience, 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
Side by side
| ISO100 Hydrolyzed Whey Protein Isolate | Gold Standard 100% Casein | |
|---|---|---|
| Our score | 8.7 / 10 | 8.1 / 10 |
| Efficacy (30%) | 9.0 | 8.3 |
| Quality & Purity (25%) | 9.0 | 7.4 |
| Value (20%) | 8.0 | 8.6 |
| Experience (15%) | 8.9 | 8.5 |
| Transparency (10%) | 8.5 | 7.8 |
| Form | Powder | Powder |
| Serving | 1 scoop (32 g)71 servings per container | 1 scoop (34 g)53 servings per container |
| Testing & certifications | Informed Choice | None verified |
| Dietary | Gluten-free | Gluten-free |
| Key ingredients |
|
|
| Flavors | 8 (Gourmet Chocolate, Gourmet Vanilla, Fruity Pebbles…) | 4 (Chocolate Supreme, Creamy Vanilla, Chocolate Peanut Butter…) |
| Creator video reviews | 5 | 3 |
Pros and cons
ISO100 Hydrolyzed Whey Protein Isolate
- 25 g of protein and about 2.7 g of leucine per 120-calorie scoop, all from whey isolate
- Informed Choice banned-substance mark on the label
- Only 2 g of carbohydrate and 1 g of sugar in Gourmet Chocolate
- Dymatize publishes a full amino acid profile for the flavor
- buyers frequently praise fast, clump-free mixing
- About $1.55 per serving for the 5 lb tub, pricier than whey blends
- Contains soy lecithin and is sweetened with sucralose (plus stevia in the current formula)
- Some buyers still report bloating despite the isolate base
- Evidence for a real-world benefit from hydrolysis is thin, so part of the premium is marketing
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
ISO100 Hydrolyzed Whey Protein Isolate
ISO100 is one of the most complete whey isolates you can buy: 25 g of protein per scoop with a published amino acid profile, minimal carbs and fat, and banned-substance certification. You pay a premium over whey blends, and the hydrolyzed angle is more marketing than proven performance edge, but for a lean, well-tested isolate that mixes easily it is a safe pick.
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 Dymatize better than Optimum Nutrition?
Are Dymatize and Optimum Nutrition third-party tested?
Who should choose Dymatize over Optimum Nutrition?
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