Role of L-carnitine in exercise training: Anti-inflammatory, antioxidant, and metabolic interactions

• Elucidates L-carnitine's antioxidant and anti-inflammatory roles • Links mitochondrial redox balance to exercise performance • Details carnitine's mechanism in fatty acid oxidation • Explores therapeutic potential in metabolic diseases • Integrates mechanistic insights with clinical outcomes L-carnitine is a mitochondria-targeted compound that plays a pivotal role in lipid metabolism, redox balance, and inflammatory regulation, particularly under conditions of elevated metabolic demands such as exercise. This review explores the multifaceted functions of L-carnitine in modulating oxidative stress and inflammation, emphasizing its relevance to exercise physiology and clinical health. By facilitating the transport of long-chain fatty acids into mitochondria, L-carnitine enhances β-oxidation and energy production while buffering excess acetyl-CoA to maintain metabolic flexibility. Its antioxidant properties, mediated through the upregulation of SOD, GPx, and catalase, help mitigate reactive oxygen species (ROS) and preserve mitochondrial integrity. Concurrently, L-carnitine suppresses cytokines such as TNF-α and IL-6, interrupting the feedback loop between oxidative stress and chronic inflammation. These mechanisms are particularly beneficial during and after exercise, where L-carnitine supplementation has shown potential to improve endurance, reduce muscle damage, and accelerate recovery in some studies, although findings across the literature are not entirely consistent. Clinical evidence also supports its therapeutic potential in conditions like cardiovascular disease, non-alcoholic fatty liver disease, and neuroinflammation. The review integrates mechanistic insights with performance outcomes, highlighting L-carnitine’s role as both a metabolic modulator and an ergogenic aid. Understanding these complex interactions provides a foundation for optimizing L-carnitine use, yet further research is warranted to clarify the optimal form (e.g., LCLT, ALCAR), dosage, duration, and target populations to maximize its therapeutic and ergogenic potential.