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Optimum Nutrition Gold Standard vs Dymatize ISO-100 Whey (2026)
Disclosure: We earn commissions on purchases made through our links. This never influences our scores. Editorial policy
The Verdict
Both products score A overall - a true tie at the top. Dymatize ISO-100 has a slight edge for lactose-sensitive users because it is a pure isolate/hydrolysate with virtually zero lactose. Optimum Nutrition wins on value with a lower cost per gram of protein. For most people, ON Gold Standard is the better value. For those who need a pure isolate, Dymatize ISO-100 justifies its premium.
Gold Standard 100% Whey
Optimum Nutrition
ISO100 Hydrolyzed Whey Protein Isolate
Dymatize
Head-to-Head Comparison
| Category | Gold Standard 100% Whey Optimum Nutrition | ISO100 Hydrolyzed Whey Protein Isolate Dymatize |
|---|---|---|
| Overall | A | A |
| Evidence | A | A |
| Quality & Purity | B+ | A |
| Value | A | B |
| Transparency | A | A |
| Cost/Day | $1.08Winner | $1.25 |
| Dose/Serving | 24g | 25g |
| Form | Whey Protein Isolate (primary) / Whey Protein Concentrate / Whey Peptides blend | Hydrolyzed Whey Protein Isolate |
| Third-Party Tested | ✓ Yes | ✓ Yes |
| Proprietary Blend | No | No |
Why This Comparison Matters
Optimum Nutrition Gold Standard and Dymatize ISO-100 are the two best-selling whey protein powders in the world. ON Gold Standard is a blend of whey isolate and concentrate. Dymatize ISO-100 is a pure hydrolyzed whey isolate. The difference matters for people who are lactose-sensitive or who want the highest protein percentage per scoop.
Both products have been around for years and have massive quality control infrastructure. Both are Informed Choice certified. The comparison comes down to protein purity, cost per gram of actual protein, and taste/mixability preferences.
We scored both on our four-factor system, treating protein purity and cost per effective dose (grams of protein) as key metrics.
Detailed Score Breakdown
Gold Standard 100% Whey
Optimum Nutrition
Whey protein isolate as primary ingredient, supported by the full body of protein supplementation research
Informed Choice certified, GMP facility; lists whey isolate as the first protein source followed by concentrate - the blend is slightly less pure than a strict 100% isolate, but isolate leads the formula
$0.90-$1.00/day at 25g protein - strong value for a certified product at this scale; one of the lowest cost-per-gram certified options on the market
Protein sources listed individually (whey isolate, whey concentrate, whey peptides), exact amounts per macro are disclosed; no proprietary blends on protein content
The world's best-selling whey protein for good reason - consistent quality, Informed Choice certified, and a fair price at full-size containers. Note that it is technically an isolate-led blend, not a pure isolate.
ISO100 Hydrolyzed Whey Protein Isolate
Dymatize
Hydrolyzed whey protein isolate - supported by protein synthesis research; hydrolysis provides marginally faster absorption, which is not a clinically meaningful advantage for most users
Informed Choice certified, GMP facility; one of the most consistently tested whey isolate products available at a non-premium price point
$1.15-$1.25/day at 25g protein - slightly above median for an Informed Choice certified isolate; the hydrolysis step adds production cost
100% hydrolyzed whey protein isolate as the sole protein source, exact macros disclosed, no proprietary blends; among the most transparent labels in this category
One of the few mainstream whey isolates that is both Informed Choice certified and uses 100% hydrolyzed isolate with no concentrate filler. The hydrolysis is a real processing distinction, even if the performance advantage over standard isolate is marginal.
How We Compared These Products
Every product in our database is scored on four equally-weighted categories: clinical evidence quality, third-party testing and purity verification, cost per clinically effective dose (not cost per pill), and label transparency. These scores combine into an overall letter grade from A+ through F.
Cost per effective dose is calculated using the clinically studied dose from published research, not the manufacturer's suggested serving. If a product requires multiple servings to reach the dose used in clinical trials, that cost is reflected in the value score.
For a full explanation of our scoring methodology, see our methodology page. Prices were last checked on the dates listed for each product and may have changed.
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FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products discussed on this page are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare professional before starting any supplement regimen.