A meta-analysis is considered the highest level of evidence because it synthesizes data from multiple randomized controlled trials (RCTs). Talenezhad et al. (2020) conducted a meta-analysis to evaluate the effects of L-carnitine supplementation on body weight and composition. The study included 37 RCTs involving 2292 participants.
Key Findings:
• Body weight reduction: -1.21 kg (95% CI: -1.73, -0.68; P < 0.001)
• Fat mass reduction: -2.08 kg (95% CI: -3.44, -0.72; P = 0.003)
• A non-linear dose-response analysis indicated that 2000 mg per day is the optimal dose for maximum effect in adults.
• No significant effect was observed for waist circumference, suggesting that L-carnitine may preferentially enhance fat oxidation in the lower extremities rather than abdominal fat.
Study link: https://pubmed.ncbi.nlm.nih.gov/32359762/