Is whey or plant protein powder better?

Whey, for most people. It has more leucine, the amino acid most tied to muscle building (about 11% of its protein, against about 7% for soy and pea), and in Consumer Reports’ 2025 tests plant powders averaged about nine times the lead of dairy ones. If you’re plant-based, soy is the one with the trial record: it matched milk for muscle in 17 trials.

Plant powders often look like the cleaner, more natural choice. Then Consumer Reports put 23 powders and shakes through a lab in 2025, and the plant ones came out with the most lead on average. The protein itself holds up better than that headline suggests, at least for soy.

Soy and pea protein are like a smaller coin of the same currency. They pay the same bill, it just takes more of them: about 40 g of soy protein to match the leucine in 25 g of whey.

How do whey, soy and pea compare?

The leucine numbers come from a 2018 lab analysis of plant protein isolates against whey and milk proteins. Plant proteins averaged 7.1% leucine and animal proteins 8.8%, with whey at about 11%.

Does plant protein build as much muscle?

Soy does. A 2025 review of 43 trials found plant protein gave slightly less muscle mass than animal protein overall. Broken down, soy against milk showed no difference across 17 trials, while the other plant proteins came out lower. Strength didn’t differ, and in people over 60 the gap in muscle mass was too small to be sure of.

That makes a soy shake a fair swap for a dairy one. Pea, rice and blends have less evidence behind them, and you’d want more protein per glass to make up for the lower leucine. protein.guide covers plant protein across the whole day.

How much lead was in the powders?

Consumer Reports measured lead per serving against its level of concern, 0.5 micrograms a day, which is cautious and has a wide safety margin. More than two thirds of the 23 products went over it. Plant-based products averaged about nine times the lead of dairy ones and twice that of beef-based ones. Dairy-based products generally had the lowest amounts, but CR still advised against daily use for half of the products it tested. It also said there’s “no reason to panic,” and that the highest levels were far below what causes immediate harm. There’s no federal limit for lead in protein powder. Our myth page on lead has the details.

What’s the plant-based shake without powder?

A cup of unsweetened soy milk (7 g) and half a cup of firm tofu (about 22 g) gets you to 29 g. Our plant glass adds a cup of frozen blueberries, half a cup of strawberries and a tablespoon of peanut butter, for 33 g of protein and an A on all six meters at 165 lb. How to make a protein shake without powder has the dairy versions too.