Systematic review reports inconsistent effects of polyphenol supplementation on skeletal muscle health in older adults

A systematic review of completed clinical trials indicates that polyphenol supplementation provides inconsistent benefits for older adults' muscle mass and strength, meaning the current evidence base is insufficient to support therapeutic recommendations.

A systematic review published in Geroscience evaluated the efficacy of polyphenol supplementation on skeletal muscle health in adults aged 55 and older across six identified randomized controlled trials.

Of the six trials, five completed studies ranging from 4 to 24 weeks in duration were synthesized, while the sixth remains an ongoing registered protocol with no results.

The evaluated interventions included quercetin, epicatechin-rich extracts, tea catechins, cocoa flavonoids, and marine-derived polyphenols.

The review reported that muscle strength improved significantly on between-group comparison in two of the five completed trials, and functional and balance outcomes improved in two of three trials assessing them.

Effects on muscle mass were inconsistent, with only one trial showing a significant group-by-time interaction under a combined polyphenol, amino-acid, and exercise intervention, while others showed null or less clearly attributable effects.

Sarcopenia is driven by underlying mechanisms such as mitochondrial dysfunction, oxidative stress, and chronic low-grade inflammation.

Although polyphenols are considered mechanistically plausible candidate modulators of these pathways in preclinical models, this review highlights a persistent gap in translating that plausibility into reproducible clinical outcomes.

Due to clinical heterogeneity and the small number of trials, a formal quantitative meta-analysis was not feasible, indicating that the current evidence base remains too small and methodologically limited to guide clinical recommendations.

The findings highlight the difficulties of establishing therapeutic efficacy within the highly heterogeneous nutraceutical and dietary supplement markets targeting sarcopenia and physical frailty.

This clinical translation barrier may reinforce the need for highly regulated, precisely targeted clinical candidates over generic antioxidant or polyphenol formulations to successfully address age-related muscle decline.

The release of outcome data from the sixth registered clinical trial protocol identified in the systematic review.

The design and initiation of larger, standardized randomized trials specifically enrolling populations with confirmed sarcopenia and utilizing direct neuromuscular assessments.