Whey and whey isolate comparison
Optimum Nutrition Gold Standard 100% Whey vs Optimum Nutrition Gold Standard 100% Isolate
ON Gold Standard Whey scores higher on our standard, 78/100 to 71/100. It earns more points for third-party testing (Informed Choice vs none found), while ON Gold Standard Isolate earns more for protein density (81% vs 77% protein by weight). Per 25 g of protein, ON Gold Standard Whey costs $1.86 and ON Gold Standard Isolate $2.35.
Both are scored out of 100 against our published standard: protein density, third-party testing, label transparency, sugar, ingredient simplicity and verified label data. Every number below is from the manufacturer's label; last checked 2026-10-13.
Optimum Nutrition
Gold Standard 100% Whey
Optimum Nutrition
Gold Standard 100% Isolate
Side by side
Per serving, from each label. Bold marks the better score, protein density, sugar and cost where the two differ. How we score
| Compared | ON Gold Standard Whey | ON Gold Standard Isolate |
|---|---|---|
| Our score | 78/100 (better) | 71/100 |
| Protein density | 22 / 3077% of each scoop is protein | 30 / 30 (better)81% of each scoop is protein |
| Third-party testing | 15 / 25 (better)Independently tested for contaminants or label accuracy | 0 / 25No verified independent testing program |
| Label transparency | 20 / 20Fully disclosed formula, no amino spiking | 20 / 20Fully disclosed formula, no amino spiking |
| Sugar | 10 / 101 g sugar per serving | 10 / 100 g sugar per serving |
| Ingredient simplicity | 6 / 10Mix of natural and artificial flavors or sweeteners | 6 / 10Mix of natural and artificial flavors or sweeteners |
| Verified label data | 5 / 57 of 7 label values verified | 5 / 57 of 7 label values verified |
| Type | Whey Blend | Whey Isolate |
| Protein per serving | 24 g | 25 g |
| Serving size | 31g (About 1 Scoop) | About 1 Scoop (31g) |
| Protein by weight | 77% | 81% (better) |
| Sugar | 1 g | 0 g (better) |
| Calories | 120 | 110 |
| Cost per 25 g protein | $1.86 (better) | $2.35 |
| Price per serving | $1.78 | $2.35 |
| Third-party certifications | Informed Choice | None found |
| Sweeteners | Acesulfame Potassium | Sucralose |
| Allergens | Milk, Soy | Milk, Soy |
| Proprietary blend | No | No |
| Added free amino acids (amino spiking) | No | No |
| Last checked | 2026-10-13 | 2026-10-13 |
Which to choose
Only the differences in our records. A value we couldn't verify never counts as a difference.
Choose ON Gold Standard Whey if…
- You want independent testing for contaminants or label accuracy (Informed Choice); we found no third-party testing for ON Gold Standard Isolate.
- You want to pay less per 25 g of protein ($1.86 vs $2.35).
- You want more flavors to choose from (22 vs 2).
Choose ON Gold Standard Isolate if…
- You want more of each scoop to be protein (81% vs 77% by weight).
- You want less sugar (0 g vs 1 g per serving).
The two powders
Good to know
Labels and prices change, so check the package before buying, especially if you have allergies. If you are pregnant, nursing, buying for a child or managing a health condition, ask your doctor before adding a supplement.