How to choose a protein powder
Read one number before anything else: protein per 100 g of powder. Across real tubs in our data it runs from 70 g to 84 g, and that spread decides what you actually get for your money. A 1 kg tub at 84% delivers 840 g of protein; the same size tub at 70% delivers 700 g. If the cheaper tub is more than 20% cheaper, it wins, and if it is not, it does not. Everything else on the label, the flavour, the isolate-versus-concentrate argument, the amino acid chart on the side, matters far less than that one division.
| Dietly label, per 100 g | Protein | Energy | Fat | Sugars | Sodium |
|---|---|---|---|---|---|
| Whey isolate | 82.0 g | 346 kcal | 1.0 g | 1.4 g | 142 mg |
| Whey isolate, another brand | 80.2 g | 372 kcal | 2.9 g | 2.9 g | 602 mg |
| Whey concentrate, vanilla | 80.0 g | 397 kcal | 6.3 g | 5.0 g | 173 mg |
| Whey concentrate, another brand | 71.4 g | 393 kcal | 8.9 g | 0 g | 0 mg |
| Whey concentrate blend | 70.0 g | 400 kcal | 5.0 g | 6.7 g | 250 mg |
| Pea protein | 77.1 g | 400 kcal | 8.6 g | 0 g | 743 mg |
| Pea protein, another brand | 80.8 g | 420 kcal | 9.2 g | 4.0 g | 912 mg |
| Organic pea protein | 75.0 g | 350 kcal | 0 g | 0 g | 900 mg |
Step 1: convert the price into price per 20 g of protein
Tub weights and scoop sizes are chosen to make comparison hard. The fix is one line of arithmetic. Multiply the tub weight in grams by the protein percentage to get grams of protein in the tub, then divide the price by that number and multiply by 20. A 1 kg tub at 80 g per 100 g holds 800 g of protein, so a 30 euro tub costs 0.75 euro per 20 g dose. A 1 kg tub at 70 g per 100 g holds 700 g, so the same 30 euro is 0.86 euro per dose, 14% more for the identical product. Do this once per candidate and the decision usually makes itself. Our protein cost calculator runs the same maths against ordinary food, which is worth doing before you buy anything, because powder is frequently not the cheapest protein on the shelf.
Step 2: decide whether you need isolate
Whey concentrate and whey isolate come from the same source; isolate is filtered further, which removes most of the fat and lactose and pushes protein per 100 g up. Our labels show the gap honestly: concentrates land at 70 to 80 g of protein with 5 to 9 g of fat, isolates at 80 to 82 g with 1 to 3 g of fat. That is a real difference and a small one, and isolate typically costs noticeably more per gram. Isolate is worth it if lactose gives you trouble, or if you are on a tight cut where 6 g of fat per 100 g of powder is genuinely part of the calculation. For everyone else, concentrate is the better purchase and the difference in outcome is not measurable.
Step 3: watch for the word blend
A blend is not automatically bad, but it is where protein percentage quietly drops. The concentrate blend in our data reads 70 g of protein and 16.7 g of carbohydrate per 100 g, against 80 g and 5.7 g for a straight concentrate. If a tub lists several protein sources plus creamers, gums and flavour systems, the protein line is where that shows up. Read it before the marketing copy about absorption curves.
Step 4: if you buy plant protein, check the sodium
Pea protein is competitive on protein content, landing at 75 to 81 g per 100 g, which is squarely in whey territory. The number that differs is sodium, because the isolation process is salt-heavy: our pea powders read 743 mg, 900 mg and 912 mg per 100 g against 0 to 602 mg for the whey products. A 30 g scoop of the highest is 274 mg of sodium, which is not alarming on its own but is worth knowing if you take two scoops a day and are also working on sodium for other reasons. Protein quality is the other consideration: pea protein is lower in methionine, which is why plant powders are often sold as blends with rice protein, and why the blend in that case is a genuine improvement rather than a dilution.
Step 5: be realistic about what powder does
Protein supplementation has a real, measured, modest effect. The best-known meta-analysis of supplementation during resistance training found a small additional gain in lean mass and strength, and it also found that the benefit shrinks as habitual protein intake rises, disappearing once total intake is already adequate. Powder is a delivery mechanism for protein you were not otherwise going to eat. If you already hit your target from food, a tub will not add anything. If you are 30 g short every day because of how your schedule works, it solves that cheaply and without cooking. Set the target first with the protein calculator, then decide whether you have a gap to fill. The protein needs explainer covers where the target comes from, and protein timing covers why the window matters less than the total.
Things the label will not tell you
- Amino spiking. Cheap tubs can inflate measured protein with added free amino acids such as glycine and taurine. A suspiciously cheap powder whose ingredient list carries several free amino acids deserves scepticism.
- Scoop drift. The per-serving panel assumes a level scoop of a stated weight. A heaped scoop is routinely 20% more powder than the label assumes.
- Sweeteners. Most flavoured powders are sweetened with sucralose or stevia rather than sugar, which is why sugars read 0 to 6.7 g per 100 g. That is a taste preference, not a health decision, for most people.
- Third-party testing. Certification schemes for banned substances matter if you compete under drug-testing rules and are irrelevant otherwise.
Once you know the protein percentage and the price, the rest is flavour preference. Look up any tub and read the protein line first.
Sources
- National Library of Medicine: protein supplementation and resistance training, 2018 systematic review and meta-analysis
- National Library of Medicine: whey protein supplementation during resistance training, 2023 review
- European Food Safety Authority: dietary reference values for protein
Common questions
How much protein should a good powder have per 100 g?
Look for 75 g or more. Real tubs in our data run from 70 g to 82 g per 100 g, and that spread changes what a tub is worth by around 20%. Anything well under 70 g is carrying a lot of something else.
Is whey isolate better than concentrate?
Only for specific reasons. Isolate reads 80 to 82 g of protein and 1 to 3 g of fat per 100 g against 70 to 80 g and 5 to 9 g for concentrate. That is worth paying for if lactose bothers you or your calories are tight, and not otherwise.
Is plant protein as good as whey?
On quantity, yes: pea powders in our data reach 75 to 81 g of protein per 100 g. On quality, pea protein is lower in methionine, which is why rice and pea blends exist. The bigger practical difference is sodium, at 743 to 912 mg per 100 g against 0 to 602 mg for whey.
Do I need protein powder at all?
Only if you have a gap. Meta-analysis of supplementation during resistance training shows a modest additional gain that shrinks to nothing once habitual protein intake is already adequate. Powder is convenience, not a requirement.