Optimum Nutrition Gold Standard vs Applied Nutrition ISO-XP.

How the numbers stack up against the price

Optimum Nutrition Gold Standard 100% Whey Protein and Applied Nutrition ISO XP sit at the premium end of the UK protein market, but they take fundamentally different approaches. Optimum Nutrition Gold Standard 100% Whey Protein is the world's best-selling protein powder - a whey blend of isolate, concentrate, and hydrolysed whey delivering 79g of protein per 100g with a taste profile that has been the industry benchmark for over a decade. Applied Nutrition ISO XP is a pure whey isolate from a fast-growing UK brand, delivering a remarkable 90g of protein per 100g with near-zero carbs and fat.

Applied Nutrition ISO XP wins on the numbers.

With 90g of protein per 100g versus 79g, you get significantly more protein per scoop - and per pound spent. The macro profile is cleaner, the ingredient list is shorter, and it typically costs less per 100g than Gold Standard. Optimum Nutrition Gold Standard 100% Whey Protein fights back with the best taste consistency in the industry (Double Rich Chocolate is genuinely hard to beat) and the trust that comes with decades of independent testing. For buyers who prioritise protein density and value, Applied Nutrition ISO XP is the better investment. For those who prioritise taste and brand heritage, Optimum Nutrition Gold Standard 100% Whey Protein remains the gold standard.