The science
peer reviewed protein
Wondering if yeast protein actually works? Fair question. It's new to most people. Researchers have spent the last few years measuring it against the leading proteins. Everything they published is below, summarized plainly and linked in full.
Matched whey,
head to head.
Does yeast protein build muscle like whey? Researchers ran the gold-standard test to find out: randomized, double-blind, placebo-controlled, nobody knew who was drinking what. Eight weeks later, the yeast group had gained as much lean muscle and strength as the whey group. And the men who weren't eating enough protein? They gained the most of anyone, while the placebo group lost muscle.
Lean mass gained · all participants
+828gabout 1.8 lb of lean muscle · yeast · 8 weeks
- Placebo
- Whey
- Yeast protein
| Group | grams of lean mass gained |
|---|---|
| Placebo | +448g |
| Whey | +741g* |
| Yeast Protein | +828g* |
Lean mass gained · men eating too little protein
+867gabout 1.9 lb · yeast — while placebo lost muscle
- Placebo
- Whey
- Yeast protein
| Group | grams of lean mass gained |
|---|---|
| Placebo | -99g |
| Whey | +440g* |
| Yeast Protein | +867g* |
*Statistically significant (p < 0.05). Left panel: significant vs own baseline; the yeast-vs-placebo difference across all participants was not statistically significant. Right panel: men eating under 1.2g protein/kg/day (48 of 79 participants) — here the yeast group's gain was significant vs placebo. Total-body lean mass by DEXA. All groups performed the same resistance-training program.
Briskey et al., 2024. Journal of Food and Nutrition Research, 12(5), 292–300.
Six months later,
still moving forward.
Protein matters more as you get older, but does yeast protein hold up in real life? In a 6-month trial, adults in their 70s took 20g a day. They walked faster and scored higher on physical-performance tests, while the group that took nothing declined. Only the yeast group improved enough for researchers to call it clinically meaningful.
Physical performance · SPPB score change
+0.9yeast — the clinically meaningful threshold · p=0.002
- No supplement
- Whey
- Yeast protein
| Group | SPPB points, change from baseline |
|---|---|
| Yeast protein | +0.9 |
| Whey | +0.3 |
| No supplement | -1.7 |
Walking speed change · m/s
+0.2m/s yeast · both proteins beat control · p=0.003
- No supplement
- Whey
- Yeast protein
| Group | metres per second, change from baseline |
|---|---|
| Yeast protein | +0.2 |
| Whey | +0.1 |
| No supplement | -0.1 |
SPPB = Short Physical Performance Battery, a standard 12-point test of balance, walking, and standing up from a chair. Between-group differences significant for SPPB (p=0.002) and walking speed (p=0.003); researchers generally consider a +0.1 m/s change in walking speed meaningful — the yeast group doubled that. Muscle mass and grip strength did not differ significantly between groups — the measured benefit was function. The control group received no supplement (not a placebo).
Bai et al., 2026. Food Science & Nutrition, 14(3), e71552.
Whey-level essentials.
No animal required.
Your body can't make nine of the amino acids it needs, they have to come from food. So researchers measured six proteins side by side: how much of the essential stuff does each one actually deliver? Yeast protein landed right next to whey, and far ahead of every plant protein tested.
| Group | mg indispensable amino acids / g protein |
|---|---|
| Whey isolate | 528 |
| Whey concentrate | 511 |
| Yeast protein | 508 |
| Soy | 398 |
| Pea | 384 |
| Wheat | 303 |
Same study · leucine — the amino acid that flips the muscle-building switch
98.6mg per g protein — nine-tenths of whey, 22–44% more than any plant
| Group | mg leucine / g protein |
|---|---|
| Whey isolate | 116.7 |
| Whey concentrate | 110.7 |
| Yeast protein | 98.6 |
| Soy | 80.5 |
| Pea | 77.3 |
| Wheat | 68.6 |
Same study · in-vivo PDCAAS (protein quality, 1.00 is the ceiling)
| Group | |
|---|---|
| Yeast protein | 1.00 |
| Whey | 1.00 |
| Soy | 0.98 |
| Pea | 0.89 |
Indispensable (essential) amino acid content per gram of protein, measured across six commercial protein isolates/concentrates. Yeast protein also recorded the highest indispensable-to-dispensable amino acid ratio (0.91) of the six, the highest valine content of all six proteins, and total BCAAs on par with whey concentrate (236 vs 239 mg/g, calculated from the paper's amino-acid table). PDCAAS measured in vivo; 1.00 is the maximum score.
Cao et al., 2025. Food Chemistry, 463, 141178.
Absorbed like whey.
The oldest knock on a non-dairy protein: "sure, but does your body actually use it?" Researchers ran yeast protein through a five-hour simulation of the human gut, the same kind of model used to study medicines, and measured how much protein was ready to absorb. The answer: the same amount as whey, down to a tenth of a percent.
One-tenth of a percent apart. Statistically, that's a tie. (And no — the other half isn't wasted. Digestion keeps going past the five-hour mark; what the test shows is that both proteins move at the same pace.)
| Group | % of protein bio-accessible after 5 hours |
|---|---|
| Yeast protein | 48.6% |
| Whey | 48.7% |
Cumulative bio-accessible protein after 5 hours of simulated gastric + small-intestine digestion (TIM-1 model). The two values were statistically comparable.
Caron et al., 2025. Food Research International, 208, 116098.
Less gas than
whey or soy.
The reason many people quit whey isn't the taste, it's how it makes them feel. Researchers fed all three proteins to real human gut microbes in a lab model (no stomachs were harmed) and measured the gas produced as each one fermented. Yeast protein made the least: 27% less than whey, 19% less than soy.
Gas produced during fermentation · indexed, whey = 100
27%vs whey · −19% vs soy — and the strongest gut-barrier support of the three
| Group | vs whey · −19% vs soy — and the strongest gut-barrier support of the three |
|---|---|
| Whey | 100 |
| Soy | 90 |
| Yeast protein | 73 |
Gas normalized per unit of beneficial short-chain fatty acids produced; index calculated from the paper's reported differences (−27% vs whey, −19% vs soy; whey set to 100). Ex-vivo model using gut microbiomes from six men aged 50–65 — not a human feeding trial. The same study found yeast protein gave the gut lining's barrier the strongest reinforcement of the three proteins.
Van den Abbeele et al., 2026. Frontiers in Microbiology, 16:1697734.
The research behind yeast protein.
Every study, strongest evidence first: what kind of study it was and what it found. No cherry-picking.
-
Human · RCT · Double-blind
Matched whey for lean muscle and strength over 8 weeks
79 men 40+, 40g/day, placebo-controlled. Yeast and whey groups both gained significant lean mass; yeast led among under-fueled eaters.
Briskey et al., 2024 · J Food Nutr Res
-
Human · RCT · 6 months
Improved physical function in adults 60+ while controls declined
92 older adults, 20g/day, 24 weeks. Walking speed and SPPB improved vs an unsupplemented control; yeast's gain met the clinical threshold.
Bai et al., 2026 · Food Science & Nutrition
-
Lab model of the human gut · 11 donors
Absorption on par with whey
48.6% vs 48.7% bio-accessible protein after 5h simulated digestion; distinct fermentation fingerprint in human microbiota.
Caron et al., 2025 · Food Research International
-
Lab study · human gut microbes
Supported gut-barrier integrity via short-chain fatty acids
In a colon model using gut microbes from older men, yeast protein produced the least gas of the three proteins tested and gave the strongest reinforcement of gut-barrier integrity.
Van den Abbeele et al., 2026 · Frontiers in Microbiology
-
Animal + lab digestion model · 6 proteins
Whey-level essential amino acids, no animal source
508 mg indispensable amino acids per g protein against whey isolate's 528, leucine at 98.6 mg/g, and an in-vivo PDCAAS of 1.00 — the ceiling.
Cao et al., 2025 · Food Chemistry
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