Optimum Nutrition Gold Standard vs Dymatize ISO100 (2026): Which to Buy

Our pick

Gold Standard

Cost

$1.49 per 25 g protein

Testing

Informed Choice

Check price

 

ISO100

Cost

$2.12 per 25 g protein

Testing

Informed Choice

Check price

Which should you buy?

• You want the most protein for your moneyGold Standard

  Gold Standard: $1.49 per 25 g of protein against $2.12 for ISO100.

• Lactose bothers youISO100

  ISO100 is all whey isolate, part of it hydrolyzed. Isolate typically has much less lactose than the whey concentrate in Gold Standard.

• You want the leaner scoopISO100, by a little

  ISO100 has 1 g of fat and 2 g of carbs a scoop, against 1.5 g and 3 g for Gold Standard.

• You want to build muscleEither

  Both give about 25 g of protein a scoop (24 g in Gold Standard, 25 g in ISO100), so either does the job.

• You want Optimum Nutrition’s own all-isolate powderOptimum Nutrition 100% Isolate

  $2.05 per 25 g of protein on Amazon. Check the price.

• You are drug-testedEither

  Both are on Informed Choice. Check that your sport accepts it. The testing section covers both, including NSF.

• You already have a tub, or you would rather get protein from mealsBuy nothing

  Finish the tub you have; switching changes the price, not the result. Powder is a convenient option, not a requirement; food can cover your protein (ISSN 2017).

Which is leaner, and is it the same protein?

ISO100 is a little leaner, and the protein is close. Both scoops have 120 calories and about the same protein: 24 g in Gold Standard and 25 g in ISO100. The real difference is the kind of whey. ISO100 uses only whey isolate, part of it hydrolyzed (pre-broken into smaller pieces). Gold Standard is a blend of isolate, concentrate and whey peptides.

The protein share is about the same: 78% of ISO100’s scoop is protein and 79% of Gold Standard’s, so Gold Standard is 1 point higher. Being all isolate shows up elsewhere: 0.5 g less fat, 25 mg less cholesterol and 1 g fewer carbs a scoop. In the other direction, ISO100 has more than three times as much sodium in chocolate, 180 mg against 50 mg, so if you watch your sodium, Gold Standard is the better fit.

Which builds more muscle?

Neither, at the same protein: the labels give no reason to expect a different result. Dymatize sells its hydrolyzed whey as faster to absorb. That is the brand’s claim, and our advice does not rest on it. How much you need a day: protein dosage guide.

Are both third-party tested?

Yes. Both powders are on Informed Choice. It screens shop-bought products for banned substances, at least monthly. Informed Choice lists the product line, not a tub size or flavor: Gold Standard as “ON Gold Standard 100% Whey” and ISO100 as “ISO100 Hydrolyzed Protein Powder (USA)”.

ISO100 was not on NSF Certified for Sport when we searched. Gold Standard’s two NSF Certified for Sport listings cover only the 10 lb tubs, not the 5 lb tub compared here. If your sport requires NSF, see which Gold Standard tubs and flavors NSF lists.

Both powders on the Informed Choice list

Every list we searched

Which is better if lactose bothers you?

ISO100, because it is all whey isolate.

Both labels list milk and soy, and neither says how much lactose is in the tub. Only Gold Standard adds lactase, the enzyme that breaks down lactose (milk sugar); only ISO100’s label says “Gluten free” and “Contains a bioengineered food ingredient”.

Gold Standard’s image is the label NSF keeps, from a 10 lb tub; the per-scoop table uses the 5 lb tub’s figures.

If lactose bothers you, look at the kind of whey. Whey isolate has much less lactose than whey concentrate. Typical isolate is about 0.5 to 1% lactose, and typical 80% concentrate is about 4 to 8%, according to the U.S. Dairy Export Council’s spec sheets (isolate, concentrate). Those are typical values, not the amount in these tubs. Whey is a milk protein, so neither powder is lactose-free or safe for a milk allergy.

Which is the better value?

Gold Standard: it costs about 30% less per gram of protein.

Both give about 25 g of protein a scoop (24 g in Gold Standard, 25 g in ISO100), so the price per gram decides. We price the cheapest ISO100 tub Amazon sells (1.3 lb, 20 servings, November 6, 2026). On Amazon (November 6, 2026), Gold Standard costs $1.49 per 25 g of protein and ISO100 costs $2.12. At 25 g of protein a day, that is about $19 a month saved with Gold Standard.

Smaller Gold Standard tubs cost more per gram: the 2 lb tub is $1.77 per 25 g.

Amazon prices move. Every protein powder we price, cheapest per 25 g first, is in protein powder prices.

More: the best protein powder, Ascent vs Gold Standard, Ghost Whey vs Gold Standard and all protein guides.

Questions

How we picked

We searched 5 testing programs’ own lists for each powder, August 25, 2026 to September 22, 2026, and captured both Informed Choice entries (October 1, 2026). Gold Standard’s per-scoop figures are from the 5 lb tub’s Double Rich Chocolate label; ISO100’s are from NIH label record DSLD 302411. We priced both tubs we link on Amazon on November 6, 2026 and pick the one that costs less per gram of protein when both are on the same testing list.

Sources

1. Labels: Gold Standard 100% Whey, Double Rich Chocolate, from the 5 lb tub’s label, with the image NSF keeps with its Certified for Sport listing (10 lb tub); and the NIH Dietary Supplement Label Database record (ISO100, Gourmet Chocolate).
2. Testing: Informed Choice certified products (both powders) and NSF Certified for Sport (Gold Standard). Searched August 25, 2026 to September 22, 2026.
3. Prices: Amazon, checked each night; last check November 6, 2026.
4. U.S. Dairy Export Council spec sheets: Whey Protein Isolate and Whey Protein Concentrate 80% (typical lactose content).
5. Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. PubMed 28642676