Lepidium Meyenii Walp. (Maca) and Blood Biomarkers of Muscle Damage and Post-Exertion Protein Degradation: A Systematic Review and Meta-Analysis of Preclinical Studies.

Background: Lepidium meyenii Walp (L. meyenii), traditionally known as maca, is widely recognized for its health-promoting properties, including potential protection against exercise-induced muscle damage (EIMD). However, its precise effect on post-exercise blood biomarkers remains unclear. Objective: This study aimed to qualitatively review research published until April 2026 examining L. meyenii supplementation to reduce blood markers of muscle damage and protein degradation post-exertion in animal studies. Specifically, the effect size (ES) of L. meyenii supplementation on post-exercise levels of creatine kinase (CK), lactate dehydrogenase (LDH), and blood urea nitrogen (BUN) was estimated. Methods: This systematic review and meta-analysis were conducted in accordance with the PRISMA guidelines. The certainty of the evidence was assessed using the GRADE framework. Relevant studies were identified through Web of Science, Scopus, SPORTDiscus, PubMed, and MEDLINE. Eligible studies included in vivo experiments in animals with controlled designs and pre-/post-intervention assessments. Methodological quality and risk of bias were evaluated using the CAMARADES tool. Statistical analysis involved standardized mean differences (SMD) using Hedges' g with 95% confidence intervals. Results: 15 studies were included in the systematic review, and 14 studies in animals in the meta-analysis. The CAMARADES scores ranged from 5 to 7 points, indicating moderate methodological quality. Supplementation with L. meyenii was not associated with statistically significant changes in LDH (SMD = -1.37; 95% CI -3.34 to 0.59), BUN (SMD = -0.37; 95% CI -2.16 to 1.42) nor CK (SMD = 0.29; 95% CI -5.45 to 6.03), with very high heterogeneity (I2 > 97%). Exploratory subgroup analyses and meta-regression analyses by formulation type and dose did not identify any moderators that could robustly explain this heterogeneity. Conclusions: The available evidence does not support a robust overall effect of L. meyenii supplementation on blood biomarkers of muscle damage or protein catabolism in animals subjected to physical stress. The high degree of heterogeneity could not be robustly explained by either the type of formulation or the dose. These findings, which are exploratory and hypothesis-generating in nature, highlight the need for standardized, well-characterized formulations and trials with adequate statistical power.