Protein & Nutrition Blog – Marmels

Bar chart of protein quality score by source: whey protein isolate 1.09, soy protein concentrate 0.90, pea protein isolate 0.82 and rice protein concentrate 0.37

Protein & Nutrition Blog – Marmels

Whey Protein vs Plant Protein: Which Is Better for Muscle?

by Mo Mandegar, PhD on Sep 10 2026
Ask a supplement aisle whether whey beats plant protein and you get a verdict. Ask a nutrition department and you get a range. Whey isolate does score 1.09 on the Digestible Indispensable Amino Acid Score against 0.82 for pea protein, but a 2025 meta-analysis of 30 randomized controlled trials found no difference in strength or physical performance. Here is where the gap is real, and where it quietly closes.