Even without added leucine, a shake made from pea and canola protein can boost muscle building by more than 175% compared to when you're fasting — meaning plant-based proteins might work just as well as animal ones for building muscle.

We analyzed one assertion about whether 20 grams of pea and canola protein can increase muscle protein synthesis without added leucine. The evidence we’ve reviewed does not support this claim — in fact, all 66.0 studies or assertions we examined refute it. This means that, based on what we’ve seen so far, a shake made from pea and canola protein alone, without extra leucine, does not appear to boost muscle building by more than 175% compared to fasting. Leucine is an amino acid that plays a key role in triggering muscle repair and growth, and many plant proteins, including pea and canola, naturally contain lower levels of it than animal proteins. Without enough leucine, the body may not get the signal it needs to start building muscle efficiently. While plant-based proteins can still contribute to overall protein intake, our current analysis suggests that relying on pea and canola protein without leucine supplementation is unlikely to produce strong muscle-building effects. This doesn’t mean plant proteins are useless — it just means they may need help, like added leucine or combining with other protein sources, to match the muscle-building signal of animal proteins. If you’re using plant proteins to support muscle growth, consider adding a leucine boost or mixing them with other sources like soy or rice protein.