Effect of Lactiplantibacillus plantarum GKK1 Supplementation on Exercise-Induced Fatigue, Muscle Damage, and Recovery in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled Trial.
Four weeks of Lactiplantibacillus plantarum GKK1 supplementation (1.0 × 10¹¹ CFU daily) was associated with attenuated post-exercise decrements in neuromuscular performance, reduced markers of muscle damage and inflammation, and more favorable endocrine and sympathoadrenal responses following exercise-induced muscle damage in healthy men.
Key Findings
Results
GKK1 supplementation was associated with smaller post-exercise decrements in countermovement jump (CMJ) performance metrics compared to placebo.
Outcomes assessed included CMJ rate of force development, relative peak force, and jump height
Measurements were taken before EIMD and at 3, 24, and 48 hours post-EIMD
Differences between groups were statistically significant (p < 0.05)
The EIMD protocol consisted of 100 maximal plyometric jumps
Participants were healthy men with no regular exercise habits
Results
GKK1 supplementation was associated with smaller post-exercise decrements in isometric mid-thigh pull (IMTP) performance compared to placebo.
Metrics assessed included IMTP relative peak force and peak rate of force development (RFD)
Differences between groups were statistically significant (p < 0.05)
Assessments occurred before EIMD and at 3, 24, and 48 hours post-EIMD
IMTP is a measure of maximal isometric strength
Results
GKK1 supplementation was associated with preserved Wingate anaerobic performance following the EIMD protocol compared to placebo.
Wingate anaerobic performance showed smaller decrements in the GKK1 group versus placebo (p < 0.05)
Wingate testing was conducted before EIMD and at 3, 24, and 48 hours post-EIMD
The Wingate test assesses short-duration maximal anaerobic power output
Results
GKK1 supplementation attenuated post-exercise increases in blood biomarkers of muscle damage, including creatine kinase (CK) and myoglobin.
Both CK and myoglobin increases following EIMD were smaller in the GKK1 group compared to placebo
CK and myoglobin are established markers of skeletal muscle damage
Blood biomarkers were analyzed following the 28-day supplementation period and EIMD protocol
Differences were statistically significant (p < 0.05)
Results
GKK1 supplementation attenuated post-exercise increases in markers of inflammation and oxidative stress, specifically hs-CRP and TBARS.
High-sensitivity C-reactive protein (hs-CRP) increases were smaller in the GKK1 group versus placebo
Thiobarbituric acid reactive substances (TBARS), a marker of lipid peroxidation and oxidative stress, were also attenuated
Differences were statistically significant (p < 0.05)
These findings suggest modulation of secondary inflammatory and oxidative stress responses following muscle-damaging exercise
Results
GKK1 supplementation was associated with more favorable endocrine and sympathoadrenal responses following EIMD, including testosterone, human growth hormone (HGH), catecholamines, and dopamine.
Testosterone, HGH, catecholamine, and dopamine responses were characterized as 'more favorable' in the GKK1 group compared to placebo
These hormones and neurotransmitters are associated with anabolic signaling and stress response to exercise
Differences were statistically significant (p < 0.05)
Results
At 24 hours post-EIMD, urinary 3-methylhistidine and the 3-methylhistidine/urinary creatinine ratio were lower in the GKK1 group than in the placebo group.
Urinary 3-methylhistidine is a biomarker associated with myofibrillar protein breakdown (muscle catabolism)
Both absolute 3-methylhistidine levels and the 3-methylhistidine/creatinine ratio were lower in the GKK1 group at 24 hours post-EIMD
This finding suggests reduced muscle protein breakdown in the GKK1 group following EIMD
Differences were statistically significant (p < 0.05)
Results
No adverse changes were observed in clinical safety biomarkers following 28 days of GKK1 supplementation at 1.0 × 10¹¹ CFU per day.
Participants received two capsules daily totaling 1.0 × 10¹¹ CFU of L. plantarum GKK1
Supplementation duration was 28 consecutive days
Clinical safety biomarkers were monitored and showed no adverse changes
The trial was registered at ClinicalTrials.gov (NCT06893549)
The study design was randomized, double-blind, and placebo-controlled with 48 healthy men (n = 24 per group)
Methods
The study enrolled 48 healthy men with no regular exercise habits who were randomly assigned to placebo or GKK1 supplementation for 28 days prior to an EIMD protocol.
Participants were randomized 1:1 to placebo (n = 24) or GKK1 (n = 24)
Supplementation was two capsules daily totaling 1.0 × 10¹¹ CFU
All participants completed 100 maximal plyometric jumps as the EIMD protocol after supplementation
Outcome assessments were performed before EIMD and at 3, 24, and 48 hours post-EIMD
Both functional performance (CMJ, IMTP, Wingate) and blood/urine biomarkers were assessed
What This Means
This research suggests that taking a specific probiotic strain called Lactiplantibacillus plantarum GKK1 for four weeks may help healthy young men recover faster from intense exercise that causes muscle damage. In this study, 48 men who did not exercise regularly were given either a high-dose probiotic supplement (about 100 billion bacteria per day) or a placebo for 28 days, after which they performed 100 maximal jumps designed to cause muscle soreness and damage. The men who took the probiotic showed less decline in measures of explosive power, strength, and anaerobic performance in the hours after the exercise compared to those taking placebo, and also had lower blood levels of proteins released by damaged muscle cells and lower levels of inflammation and oxidative stress markers.
The probiotic group also showed lower levels of a urine marker called 3-methylhistidine at 24 hours after exercise, which is associated with the breakdown of muscle protein. Additionally, hormones and chemicals related to muscle building and stress response — including testosterone, human growth hormone, and dopamine — showed patterns that were considered more favorable in the probiotic group. No safety concerns were identified over the course of the supplementation period.
This research suggests that L. plantarum GKK1 may be a safe nutritional strategy to support muscle recovery after strenuous exercise, potentially by reducing muscle breakdown, dampening inflammation and oxidative damage, and supporting a more favorable hormonal environment. These findings are relevant to athletes, coaches, and anyone interested in recovery nutrition, though further research in different populations and exercise conditions would be needed to generalize these results.
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Lee M, Chen C, Shih Y, Tsai Y, Lin S, Chen Y, et al.. (2026). Effect of Lactiplantibacillus plantarum GKK1 Supplementation on Exercise-Induced Fatigue, Muscle Damage, and Recovery in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled Trial.. Nutrients. https://doi.org/10.3390/nu18172782