Years may have passed since Arnold Schwarzenegger stepped away from competitive bodybuilding, but the six-time Mr. Olympia still keeps a close eye on the sport. Through his newsletter, he often busts myths, and this time, he got real about soy protein, calling it one of the best.

In his latest edition of Arnold’s Pump Club, Arnold examined 43 randomized studies and expressed that the myth of dairy protein being better than soy protein might have very little truth to it.

A 2025 meta-analysis of 43 randomized controlled trials found that soy protein produces comparable muscle gains to dairy protein. If you’ve been avoiding soy because someone told you it’s a poor muscle-building protein, the evidence says otherwise,” He wrote in his Newsletter.

Is Arnold right? Well, it appears he might be. According to 30 randomized studies published on PubMed, animal protein performed slightly better in people under 60, but the difference is insignificant. In adults over 60, the effects are virtually the same.

However, Arnold Schwarzenegger cautioned that by plant protein, he meant taking soy protein and not other sources of protein such as Tofu, Chia seeds, and others, “It’s worth noting that the research tested soy protein supplements, not specifically foods like tofu, edamame, or tempeh.”

But that doesn’t mean you need to completely stay away from them. “That said, whole-food soy-based foods have meaningful protein quality on their own. Soy is a complete protein, containing all nine essential amino acids.” Now, the question is, how to make plant-based protein more powerful? Arnold has the answer to that as well.

How To Make Plant-Based Protein More Powerful By Arnold Schwarzenegger

Plant-based protein works on equal terms with animal protein, but what it lacks is leucine, which plays a key role in stimulating muscle protein synthesis. “To be clear, plant-based proteins are perfectly healthy, but because they contain fewer amino acids (leucine in particular),” Arnold writes in his Newsletter.

So, how do you make the best of it? Well, according to Arnold, adding leucine to plant-based protein creates the perfect balance, “When participants consumed 20 grams of plant protein with an additional 1.5 grams of leucine, muscle protein synthesis was similar to that of 20 grams of whey protein.”

Another simple approach would be to increase total plant-based protein consumption, but that would also increase overall caloric intake.

What do you think? Would Soy Protein be a thing?

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Written by

Suryakant Das

Edited by

Joyita Das