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Evidence-Based Supplement Research
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Big effect

L-carnitine linked to 1.1 kg weight loss in umbrella meta-analysis, but high heterogeneity throws cold water on the finding

This analysis of 3 meta-analyses found a statistically significant average weight loss of about 1.1 kg with L-carnitine, but the extreme variability (I²=90.6%) and low overall evidence strength mean the true effect could be much smaller or even zero.

An umbrella meta-analysis of L-carnitine supplements found a statistically significant average reduction in body weight of about 1.1 kg compared to placebo. However, the results across individual studies were highly inconsistent, with an I² value of 90.6% indicating almost all the variation is due to true differences between studies rather than chance. This weakens the overall confidence in the finding, and the evidence is considered low strength.

Where this fits in the evidence

Pillser has synthesized 4 studies on L-Carnitine for Reduced Body Weight — overall evidence strength: Moderate.

Across 4 studies, all reported beneficial effects of L-carnitine supplementation on reducing body weight, with effect sizes ranging from small to large and a predominant moderate effect. The most-studied dose was 3000 mg/day, and effects were typically observed in clinical populations such as women with PCOS or individuals with overweight/obesity. Median study duration was 49 days (7 weeks), suggesting effects may appear within 6-8 weeks of supplementation.

The study

The Effect of the L-Carnitine Supplementation on Obesity Indices: An Umbrella Meta-Analysis.

  • Meta-Analysis
  • n = 352
  • 2025-04-28
  • International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition
More on L-CarnitineMore on Reduced Body Weight

This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.

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