Plant protein vs soy protein: what's different

"Plant protein" isn't one ingredient — soy, pea, rice, hemp and fava bean are separately sourced proteins with their own amino acid profiles and their own (often very different) amounts of trial evidence. Soy protein has the most direct evidence of any of them. Electric Tiger Plant Protein is built on fava bean protein isolate and fermented yeast protein instead, and doesn't contain soy.

What sets soy protein apart

Soy protein isolate is one of the most-studied plant proteins for muscle and strength outcomes, and the trial evidence reflects that. A 2018 meta-analysis of 9 randomized controlled trials (266 adults performing resistance training for at least 6 weeks) found soy protein supplementation produced similar muscle mass and strength gains to whey or other animal proteins. That's the most direct head-to-head result in the plant-protein literature — most other plant sources, fava bean included, don't have a comparable body of trials testing them against animal protein specifically.

Does our fava bean and yeast blend contain soy?

No. Checking the full ingredient list — Fava Bean Protein Isolate, YESTEIN™ Fermented Nutritional Yeast Protein, Nidau Cocoa Powder, Natural Flavor, MCT Oil Powder, Nightfall Black Cocoa Powder, Apple Pectin Powder, Sea Salt, Sunflower Lecithin, Stevia Extract (leaf) — there's no soy protein or soy-derived ingredient on the panel. If you're specifically searching for a soy-free plant protein, that's a straightforward label fact you can verify yourself rather than take our word for. If you have G6PD deficiency or a family history of it, read who should not take fava bean protein before trying any fava-bean-based product — a separate consideration from the soy question above.

Does that mean it works the same as soy?

Not necessarily, and we're not going to imply it does. Soy's muscle-building evidence — the 2018 meta-analysis above — was measured for soy protein specifically, at doses and in trial protocols that didn't include fava bean or fermented yeast protein. No trial we found has tested a fava bean and yeast blend against soy, or against animal protein, under the same conditions. "As good as soy" isn't a claim this label can make, and we're not making it. See how to choose a good plant protein for how to weigh a label's own evidence gap when comparing plant protein sources.

Why someone might want soy or avoid it

Soy is one of the nine major food allergens the FDA requires labeling for in the US, so anyone with a soy allergy needs to check a product's ingredient list regardless of what the front-of-package category label says — "plant protein" alone doesn't tell you whether soy is in the blend. Outside of allergy, some people simply prefer to avoid soy for personal or dietary reasons unrelated to any health claim about it. Either way, checking the actual ingredient list is the reliable way to know — the category name isn't.

Questions people ask

Is soy protein or plant protein better?

Soy protein is a plant protein — the comparison is really soy against other plant sources like pea, rice or fava bean, which vary in how much trial evidence exists behind each one. Soy currently has the most direct comparative evidence for muscle and strength outcomes among the plant proteins we've reviewed.

Does Electric Tiger Plant Protein contain soy?

No. It's made from fava bean protein isolate and YESTEIN™ fermented nutritional yeast protein — no soy protein or soy-derived ingredient appears on the label.

Why do some plant protein brands avoid soy?

Soy is a major food allergen, and some buyers specifically look for a soy-free option for allergy, sensitivity or personal preference reasons. A brand choosing a different plant protein source — pea, fava bean, rice — sidesteps that allergen by ingredient choice rather than through any special processing.

Related reading: what is plant protein? a plain guide, how to choose a good plant protein, and plant protein without fillers.