Yeast-Whey Protein Blend Cut Average Soreness 1.43 Points in Male Athletes

A three-arm trial in competitive Chinese athletes tested a yeast protein and whey blend against whey alone and against water after a deliberate bout of muscle damage. The yeast protein blend beat water on several recovery measures in the men, but it did not clearly beat whey.

Yeast protein is moving from an ingredient question into a recovery question, and a randomized controlled trial published online on October 14, 2026 in Nutrients is one of the first to put it against whey in trained athletes. Across 48 analyzed participants, the blend was associated with smaller immediate strength losses and lower average soreness than a water-only control in male athletes.

The work came from Chunyan Xu, Lijing Gong, Zhen Ni and corresponding author Xintang Wang at Beijing Sport University and the China Institute of Sport and Health Science in Beijing. The trial was registered as ChiCTR2400090476 and carried ethics approval number 2024089H, dated March 20, 2024.

Fifty-four first-class or master-level athletes were recruited, 18 to each of three arms and randomized by sex. Six withdrew for scheduling reasons before any outcome data were collected after randomization, leaving 48 for analysis: 7 women and 8 men on the yeast protein blend, 8 and 9 on whey, and 8 and 8 on water.

Disciplines included basketball, football, volleyball, martial arts, track and field and ice sports, with volleyball the largest single group. Habitual protein intake averaged about 1.2 grams per kilogram of body mass a day, rising to roughly 2.1 grams per kilogram in the supplemented arms.

How the Yeast Protein Trial Was Built

The blend arm received a product that was 40% yeast protein ingredient and 40% whey protein isolate. The whey arm received 80% whey protein isolate. Both delivered 0.9 grams of supplemental protein per kilogram of body mass a day, matched so the two arms took in the same nitrogen.

Athletes supplemented for seven days first. On day 8 they completed a bilateral isokinetic knee-extension protocol designed to produce exercise-induced muscle damage, then continued supplementing through the 48-hour assessment. A final measurement came at 72 hours, on day 11.

Outcomes were taken before the damage protocol, immediately afterwards, and again at 24, 48 and 72 hours. The battery covered creatine kinase, interleukin-6, perceived soreness, countermovement jump, maximal voluntary isometric contraction and eccentric peak torque in both legs.

Men and women were analyzed separately. That decision is important for reading the results, because the sample was not powered to compare the sexes directly, and almost every significant signal landed on the male side.

Strength Loss Was Smaller in the Men Who Took the Blend

The clearest finding sits in the immediate strength drop after the damage protocol. Compared with water, men on the yeast protein blend lost 40.75 newton-metres less in left-leg maximal voluntary isometric contraction, confidence interval 11.38 to 70.12, p = 0.009, Hedges g = 1.36.

On the right leg the equivalent gap was 46.09 newton-metres, confidence interval 9.99 to 82.20, p = 0.015, g = 1.25. Right-leg eccentric peak torque showed the largest separation of all: 71.03 newton-metres, confidence interval 28.88 to 113.19, p = 0.002, g = 1.65.

That eccentric torque result was the only functional outcome to survive the authors broader false-discovery-rate correction, at q = 0.037. Everything else in the functional battery is best read as exploratory.

Women were not left out entirely. In the right-leg isometric measure, the acute decline was smaller than control by 29.38 newton-metres on the yeast protein blend, p = 0.016, g = 1.28, and by a nearly identical 28.88 newton-metres on whey, p = 0.015, g = 1.26.

Creatine Kinase Moved in Two Directions

Creatine kinase, a blood marker that rises as muscle fibres are stressed, did not behave in a single direction. Immediately after the damage protocol, men on the yeast protein blend had higher creatine kinase than controls, a geometric mean ratio of 1.800, confidence interval 1.238 to 2.617, p = 0.029.

By 48 hours the relationship had reversed. The same comparison produced a ratio of 0.524, confidence interval 0.360 to 0.761, p = 0.011, meaning roughly half the control level at the point where damage markers usually peak.

In the women, creatine kinase was lower on the blend at 24 hours, ratio 0.509, confidence interval 0.350 to 0.741, with a Holm-adjusted p of 0.006. The authors label this exploratory because the underlying interaction did not clear their correction, at q = 0.071.

Soreness and Interleukin-6 Favored the Blend in Men

Averaged across all assessment points, male athletes on the yeast protein blend reported soreness 1.43 points lower than controls on the visual analogue scale, confidence interval -2.47 to -0.39, adjusted p = 0.021. Whey alone came to -1.15 against control and fell just short of significance at p = 0.051.

Interleukin-6, an inflammatory signalling molecule, was lower immediately after the protocol in the blend group, ratio 0.510, confidence interval 0.327 to 0.795, Holm-adjusted p = 0.044. Whey alone did not differ significantly from control on that measure.

Neither pattern appeared in the women after adjustment. Previous FLM coverage of essential amino acids and soreness after eccentric exercise found similarly modest soreness effects from a different supplement class.

Jump Height Held Up Better, With a Caveat

Countermovement jump told a consistent story in the men. Against water, the yeast protein blend was associated with 12.63 percentage points better performance immediately after the protocol, p less than 0.001, then 10.13 points at 48 hours, p = 0.006, and 12.88 points at 72 hours, p less than 0.001.

Those are large separations, but they became exploratory under the broader correction, at q = 0.072. Whey alone showed an advantage only at the 72-hour point.

Jump testing is a common fatigue proxy precisely because it is quick and repeatable, though as our report on how countermovement jump tests are used to track fatigue noted, protocols vary so widely between labs that cross-study comparison is difficult. The damage protocol here leaned on eccentric knee-extension work, the same stimulus examined in research on eccentric training and countermovement jump gains.

What Yeast Protein Did Not Beat

The comparison most readers will care about is the blend against whey, and that is where the trial is quiet. Those contrasts were largely nonsignificant, which means the data cannot show the yeast protein blend outperforming a conventional whey protein isolate at the same protein dose.

The authors describe their pattern of results as an outcome-specific response rather than a uniform effect. Some markers moved, others did not, and the ones that moved did not all move at the same time points.

That framing is the honest one for a trial of this size. It also means the practical claim available from this work is narrow: a yeast protein and whey blend can sit alongside whey rather than replace it, on this evidence.

How to Read a Yeast Protein Result in Practice

Nothing here changes a basic protein target. The supplemented athletes were already eating about 1.2 grams per kilogram a day before the trial added 0.9 more, which puts them well above common training recommendations rather than at the edge of a deficit.

Two cautions are worth holding. The first is design: a water control tells you whether protein helps, not whether this protein helps more than the protein most athletes already use. The second is scale, because 15 men in a blend arm cannot settle a question like this.

• If you already use a whey product and recover adequately, this trial gives no reason to switch to a yeast protein blend.
• If you are interested in plant and fermentation-derived protein sources for other reasons, the trial is mildly reassuring on recovery, not conclusive.

Supplement decisions also sit downstream of training and sleep, and individual needs vary; anyone with a medical condition or on medication should speak to a clinician before adding a product. For context on how single-ingredient supplement trials usually read, see our report on creatine and lean tissue in middle-aged adults.