Whey, casein and plant proteins compared on dose, testing, taste and value
Top picks
Transparent Labs
A grass-fed whey isolate with 28 g of protein per scoop, stevia instead of artificial sweeteners, and NSF Certified for Sport status.
Optimum Nutrition
The benchmark whey blend: 24 g of protein per 120-calorie scoop, Informed Choice certified, and a flavor lineup few rivals can match.
An all-isolate whey with a hydrolyzed fraction: 25 g protein and about 2.7 g leucine per 120-calorie scoop, with Informed Choice testing.
The essentials
Protein powder is a concentrated, convenient source of protein, usually made from milk (whey or casein) or from plants such as pea, rice and pumpkin seed. It does nothing that food cannot do, but it makes a daily protein target easier to hit, especially for people who train hard, eat on the go or follow plant-based diets.
The evidence behind it is solid. A 2018 meta-analysis of 49 randomized trials found that protein supplementation modestly increased gains in strength and fat-free mass during resistance training, with little extra benefit once total intake passed about 1.6 g per kilogram of body weight per day. The International Society of Sports Nutrition recommends 1.4 to 2.0 g/kg/day for most exercising people, in doses of roughly 20 to 40 g spread every three to four hours, and notes that 30 to 40 g of casein before sleep can raise overnight muscle protein synthesis.
What separates a good powder from a mediocre one is rarely the marketing. It comes down to protein and leucine per scoop, third-party testing, sweeteners and additives, and price per serving, which are the factors our reviews focus on.
Every product
13 products
Transparent Labs
A grass-fed whey isolate with 28 g of protein per scoop, stevia instead of artificial sweeteners, and NSF Certified for Sport status.
Optimum Nutrition
The benchmark whey blend: 24 g of protein per 120-calorie scoop, Informed Choice certified, and a flavor lineup few rivals can match.
An all-isolate whey with a hydrolyzed fraction: 25 g protein and about 2.7 g leucine per 120-calorie scoop, with Informed Choice testing.
A naturally sweetened whey isolate from Truly Grass Fed-certified Irish milk, with Labdoor certification and batch lab reports linked online.
Optimum Nutrition
A slow-digesting micellar casein with 24 g of protein per scoop for bedtime or long gaps between meals; thick, filling and fairly priced.
Vega's sport protein, formerly Vega Sport Premium Protein: 30 g plant protein, tart cherry and a probiotic per scoop, NSF Certified for Sport.
Garden of Life
A 30 g vegan protein built for athletes: organic pea and bean proteins, NSF Certified for Sport, plus recovery botanicals and a probiotic.
Myprotein
Juice-style clear whey: 20 g protein in an 80-calorie, sugar-free scoop with Informed Choice certification, though foaming and flavor split reviews.
Momentous
A premium grass-fed whey isolate with 20 g of protein per 90-calorie scoop, NSF Certified for Sport status and a short, gum-free ingredient list.
Naked Nutrition
A one-ingredient grass-fed whey concentrate: 25 g protein per 30 g serving with no sweeteners or additives; plain-tasting and best blended.
GHOST
The cereal-and-dessert flavor king: a fully disclosed whey blend with 25 g protein per scoop, but no third-party certification and a premium price.
A true zero-carb whey isolate: 25 g of protein plus a broad vitamin and mineral blend in a 110-calorie scoop, at a price above most rivals.
A budget USDA Organic vegan blend with 21 g protein and 7 g fiber per serving; a 2026 heavy-metals lawsuit against Costco is a key caveat.
Buying guide
The five things we look at first — and what they mean for you.
Whey concentrate is the most affordable and contains a little lactose; whey isolate is filtered to remove most lactose, fat and carbohydrate; hydrolyzed whey is partially pre-digested. Casein digests slowly and suits bedtime or long gaps between meals. Plant blends such as pea with rice or pumpkin seed work for vegans and dairy-sensitive people, and combining sources helps cover every essential amino acid, since some single plant proteins run low in one.
Look at grams of protein per serving, not per tub, and check the serving weight: a 34 g scoop with 24 g of protein is about 70% protein, while some plant powders need two scoops to reach 21 g. Divide the price by the number of servings, then by grams of protein, to compare fairly. Serving counts can also differ between flavors of the same tub size, so check the exact flavor you plan to buy.
Independent testing is the best way to know a tub contains what the label says. NSF Certified for Sport and Informed Choice or Informed Sport screen for substances banned in sport, while NSF contents certification checks that label amounts are accurate and contaminants stay within limits. Look the product up in the certifier's online database rather than trusting a logo, because certification is granted by product and flavor, and sometimes by lot.
Avoid proprietary blends that hide amounts, and favor brands that publish an amino acid profile. Some products have been criticized for amino spiking, adding cheap free amino acids that inflate the protein figure without supplying complete protein. A disclosed leucine content of roughly 2 to 3 g per serving and an ingredient list without added glycine, taurine or similar amino acids are good signs.
Many flavored powders use sucralose or acesulfame potassium; others rely on stevia or monk fruit, and unflavored versions skip sweeteners entirely. Gums and lecithin improve texture but bother some stomachs. Heavy metals are a growing concern: Consumer Reports' 2025 testing, as cited by the Texas attorney general, found lead in plant-based powders averaged about nine times the level in dairy-based ones. Rotating products and choosing brands that publish contaminant testing reduces risk.
Head to head
Ingredients
Video reviews
Key sources
Learn
From the 0.8 g/kg RDA to the new 1.2–1.6 g/kg guideline: daily protein targets by goal, grams by body weight, per-meal timing, and advice for aging, dieting and vegans.
Nutrition Reviews Editorial Team · Sep 28, 2026
What USP, NSF and Informed Sport seals actually test, how to verify a certification in two minutes, how to read a certificate of analysis, and where testing stops.
Nutrition Reviews Editorial Team · Sep 28, 2026
Protein %, lactose, leucine, digestion speed and cost per 25 g of protein: what separates whey concentrate, isolate and hydrolysate, and how to spot spiked labels.
Nutrition Reviews Editorial Team · Sep 28, 2026
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