Across 3 studies, all reported beneficial effects of L-carnitine on reducing HOMA-IR, with effect sizes predominantly small to moderate. The most consistent evidence comes from two meta-analyses and one systematic review, all of which found statistically significant reductions. The most studied dose range was ≥2 g/day, and effects were observed primarily in adults with overweight/obesity.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Available evidence is overwhelmingly positive, but clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Additionally, dose and form were not consistently reported, and study durations varied, limiting the ability to pinpoint optimal use.
significant effects of L-carnitine on ... HOMA-IR (MD = -0.58, 95% CI: -0.77 to -0.38)
L-carnitine emerged as the most effective and consistent intervention, producing significant reductions in body weight, body mass index (BMI), waist circumference, fasting blood glucose, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and LDL-Cholesterol (LDL-C), along with a significant increase in HDL-Cholesterol (HDL-C).
L-carnitine supplementation had a significant effect on ... homeostasis model assessment-estimate insulin resistance (HOMA-IR) [WMD = -0.73; 95% CI, -1.21 to -0.25; p = 0.003]