As a physician, I have spent money on protein powder for years without really understanding why there are so many different blends. It was not until I researched this issue that I learned how to read the label. Every tub in the aisle promises more muscle, and the grams on the back of the bottle make it look simple. It is not. Those grams tell you how much protein you swallow, not how much your body can actually use to build muscle. Two powders can both say 25 grams, and one can still fall short.

Last issue we covered how much protein you actually need. This issue is the buyer's guide: which powder is worth your money, which ones are overhyped, and the point where the choice stops mattering. Let us go through it with the numbers.

Watch the 10-minute whiteboard explainer:

For building muscle, the type matters less than the marketing suggests, but mainly once your total intake is high. In a 10 week study, young adults who trained built the same muscle on a plant based diet as on a meat diet. Read the fine print though: both groups ate about 2 grams of protein per kilogram a day, which is a lot, and the plant diet leaned heavily on mycoprotein, a high quality source. So the type can stop mattering, but only when total protein is being met. If you eat closer to 0.8 to 1.0 grams per kilogram, the source likely matters, because you are only in a small surplus (Monteyne et al., J Nutr 2023; Hevia-Larrain et al., Sports Medicine 2021).

Two things change this. After about 65, the source matters more, because older muscle responds less to protein. And if you lean on only one kind of plant source for your protein, you can fall short on one amino acid. We will come back to both.

Every protein is built from 20 small building blocks called amino acids. Nine of them are essential, which means your body cannot make them and food must supply them. Two things decide how good a protein is for muscle: how many essential amino acids it has, and how much of one in particular, leucine, which is the biggest stimulator of muscle building (Gorissen et al., Amino Acids 2018).

Animal proteins like whey, milk, and egg have all of them in good amounts. Most plant proteins are a little short on one. Beans, pea, and soy tend to be low in methionine. Grains, rice, and hemp tend to be low in lysine. That gap is why plant eaters sometimes mix sources.

Quality is scored by DIAAS, which stands for the Digestible Indispensable Amino Acid Score. It measures how much of a protein your body can actually absorb and use. A score of 1.0 or higher means top quality with nothing missing. Below 1.0 means it falls short on at least one amino acid.

Whey scores 1.09 to 1.38, soy 0.90 to 1.17, pea 0.82 to 0.94, and brown rice only 0.37 to 0.60 (Lee et al., J Nutr 2016; Gorissen et al., Amino Acids 2018). A low score does not mean a protein is useless. It means it is potentially short in one place, which can be fixed by pairing foods.

Whey, from milk, is the best single powder for muscle. It has the most leucine at about 11 percent, the fastest digestion, and the top quality score. Paired with exercise it even trims LDL cholesterol by about 5 mg/dL, an effect seen mainly in adults under 50 and smaller in those who are overweight (Prokopidis et al., Clin Nutr 2025). Casein is its slower digesting cousin, also from milk. At adequate doses it builds a similar amount of muscle overall, though it works slower and gives a weaker signal right after a workout, while its steady release may help overnight (Tang et al., J Appl Physiol 2009).

Soy is the strongest single plant option, nearly complete, and it modestly lowers LDL cholesterol, by about 6 mg/dL, and blood pressure (Zhou et al., Clin Nutr 2024). Pea is the best of the rest, but it is low in methionine, so it can be paired with rice, which is low in lysine. Together they are complete and match whey at adequate doses (West et al., Am J Physiol Endocrinol Metab 2023). A pea and rice blend only matters if pea is your main protein. If your diet is varied, pea on its own is plenty. Keep one thing in perspective: per serving the gaps are real. Matched doses of whey beat soy by about 31 percent and casein by about 122 percent for muscle building right after exercise, and plant proteins usually need a bigger scoop, 25 to 40 grams, to hit the leucine threshold. Those gaps shrink to little once your total daily protein is high (Tang et al., J Appl Physiol 2009; Pinckaers et al., Sports Medicine 2021).

Brown rice, hemp, and chia are weak for building muscle. Hemp and chia are rich in fiber and plant omega 3s, so enjoy them as foods, just not as your main muscle protein. One thing to know: the fiber packed into hemp and chia slightly lowers how much of their protein you absorb. If your main goal is muscle, take your main dose from a low fiber option. However, fiber should also be prioritized in your daily diet.

Mycoprotein, the protein in Quorn, has the single biggest cholesterol effect here, dropping total cholesterol by about 21 mg/dL, though that comes from a handful of small, short trials (Shahid et al., Am J Clin Nutr 2023). Two things to know: it is not a mushroom, it is a separate thread like fungus called Fusarium, so do not confuse it with the mushroom protein powders sold online. And you get it by eating Quorn foods, not by scooping a powder. It simply is not sold as one.

Not really. Two tablespoons of peanut or almond butter give about 7 grams of protein, but both are low quality and your body cannot use all of it. Peanut is very low in lysine, and almond is low in the sulfur amino acids. To match the usable protein in one 25 gram scoop of whey, you would need roughly 5 to 6 servings of peanut butter, around 1,000 calories. That is based on an assumption of about 7 grams of protein per serving and peanut's low digestible score (Gorissen et al., Amino Acids 2018). Enjoy nut butters for their healthy fats and micronutrients, not as your main protein.

If you eat a balanced, varied diet, you do not need to mix proteins on purpose. You are already combining foods across the day. Per serving a better protein does build a little more, but once your total daily intake is high, that difference mostly disappears (Trommelen et al., Sports Medicine 2019).

For an omnivore with meat in the diet, any powder works. For a vegetarian who gets protein from several sources, pea or soy work well. If you cannot say your sources are varied, whey is the safe choice. For a vegan, whey is off the table, so spread your protein across varied sources through the day, with soy the most complete single plant option (Monteyne et al., J Nutr 2023).

Protein does more than build muscle. Adding it to a meal with carbs cuts the after meal blood sugar spike by about half in people without diabetes (Wolever et al., J Nutr 2024). Higher protein diets modestly lower cholesterol and blood pressure, and plant proteins edge out animal ones (Yao et al., Nutrition Reviews 2025). Protein is also the most filling of all the nutrients, nudging the same gut hormones (GLP-1 and Peptide YY) that the new weight loss drugs target, with whey especially good at it (Belza et al., Am J Clin Nutr 2013).

Plant powders carry more heavy metals than dairy based ones, with brown rice protein the worst for arsenic, lead, and cadmium. At one scoop a day, about 30 grams, the risk stays low. Above that, especially with rice protein, it climbs (Chen et al., Environ Res 2026). If you use large daily amounts, pick a product that is third party tested, such as NSF Certified for Sport or Informed Sport, and a doctor can check your actual levels with a urine and blood test.

Two parts. First, your age sets how much. Younger adults can hold muscle near the old 0.8 grams per kilogram a day, but aim for 1.2 to maximize muscle growth and stop at about 1.6. For healthy older adults, guidelines suggest at least 1.0 to 1.2 grams per kilogram a day, and 1.2 to 1.5 if you are ill or frail (Deutz et al., Clin Nutr 2014). The full breakdown is in the last issue.

One caution on that target: it is based on your total body weight, which works fine at a normal weight. If you are overweight and base your protein goal on total weight, you will overestimate how much protein you need, because fat tissue needs very little. In that case base it on your fat free mass or use your ideal or adjusted body weight. The last issue shows how to calculate it.

Second, your diet decides how much the powder matters. Omnivore, any powder works. Vegetarian, pea or soy. Vegan, spread varied sources through the day and consider soy the most complete source of amino acids. One age note: after about 65, muscle responds less to protein and the source starts to matter more. Observational data modestly favor animal protein for older muscle, though the evidence is imprecise, so a fast, high leucine protein like whey is a reasonable pick to clear the higher per meal threshold. A varied diet can still get there (Mendes et al., J Acad Nutr Diet 2026; Campbell et al., J Gerontol A 2023).

Here is the whole field in one place.

You probably know someone agonizing over which expensive tub to buy, or a plant eater who worries they cannot build muscle without meat. Share this, because the choice is simpler than the marketing makes it look, and it is worth a conversation with their doctor. That is how Pareto Life grows.

Catch up on the series

How Much Protein After 40: The Right Amount by Age · VO2 Max by Age: How to Test It at Home, and Add Years to Your Life

Next, I will cover dairy. Milk, yogurt, and cheese. What the evidence supports, what the marketing oversells, and what to skip.

References

Monteyne et al., J Nutr 2023 · Hevia-Larrain et al., Sports Medicine 2021 · Gorissen et al., Amino Acids 2018 · Lee et al., J Nutr 2016 · West et al., Am J Physiol Endocrinol Metab 2023 · Trommelen et al., Sports Medicine 2019 · Tang et al., J Appl Physiol 2009 · Pinckaers et al., Sports Medicine 2021 · Mendes et al., J Acad Nutr Diet 2026 · Prokopidis et al., Clin Nutr 2025 · Zhou et al., Clin Nutr 2024 · Deutz et al. (ESPEN), Clin Nutr 2014 · Campbell et al., J Gerontol A 2023 · Shahid et al., Am J Clin Nutr 2023 · Chen et al., Environ Res 2026 · Wolever et al., J Nutr 2024 · Yao et al., Nutrition Reviews 2025 · Belza et al., Am J Clin Nutr 2013 · 2025 joint advisory on nutrition for obesity management