Whey Protein Powder

Food · Protein · Food, Typed Supps

Eighty-five per cent protein, and the most-studied protein supplement there is.

Stage by stage

Soluble (Stomach): Stays soluble at stomach pH, so it empties fast rather than curdling.
Rapid absorption (Small intestine): Produces a quick, short-lived rise in blood amino acids.
Leucine trigger (Muscle): High leucine content activates the pathway that switches on protein synthesis.
Iodine (Thyroid): 240 mcg per 100 g from the dairy source — a substantial load for heavy users.

What the evidence supports

Augmenting muscle gain alongside resistance training — strong evidence. Meta-analysis supports protein supplementation for hypertrophy, with benefit plateauing around 1.6 g/kg/day of total protein — so the operative variable is daily total, not the supplement.
Requiring intake within 30 minutes of training — insufficient evidence. The anabolic window was oversold. Once total daily protein is controlled, timing effects are small.

Timing

The anabolic window was oversold. Total daily protein is what the trials actually show, and the timing effects are small beside it.

Time to effect

Weeks–months: Hypertrophy from training plus adequate protein.
~1.6 g/kg/day: Where the benefit of additional protein plateaus.

Allergens

Contains: Milk. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegetarian, Pescatarian, Halal, Kosher, Keto, Gluten-free. Depends on the product: Low-FODMAP.

Satiety

Not scored: the satiety index is measured on 240 kcal servings, and nobody eats a 240 kcal serving of this. The question does not apply rather than the answer being unknown.

Cost band

Pricey — roughly £25 per kg, as a band midpoint rather than a price.

Key nutrients

Protein
Iodine
Selenium

Nutrition per 100g

Calories: 375
Protein: 85g
Carbohydrate: 1.6g
of which sugars: 1.3g
Fat: 2.2g
of which saturated: 1.2g
Fibre: 1.8g
Sodium: 200mg

Food vs. supplement

Whey is the rare supplement where the evidence is good and the conclusion is still "you probably do not need it": the benefit tracks total daily protein, so it only helps if it is how you reach your target rather than an addition on top of it.

Kitchen tip

Work out your daily protein target first. If food already gets you there, the powder is convenience and nothing more.

Common myth

“You have to get your protein in within 30 minutes of training.” In reality: That window was much narrower in the marketing than in the evidence. Once total daily protein is accounted for, timing effects are small — meta-analyses consistently find the daily total is what drives the result. Around 1.6 g per kilogram of body weight a day is where additional protein stops adding anything measurable, whatever form it arrives in.