Research synthesisModerate evidenceSmall effect6 studies · 4 beneficial · 2 neutral · 0 harmful
Across 6 studies (4 meta-analyses, 1 systematic review, 1 review), 4 reported a beneficial small effect of L-carnitine on reducing body mass index, while 2 found no significant effect. The most studied dose range was 1–2 g/day, and effects were typically observed in clinical populations (e.g., type 2 diabetes, overweight/obesity) over a median duration of 56 days (8 weeks). The predominant effect size is small, with one study reporting a moderate effect.
- Effective dose range: 1–2 g/day
- Studied populations: clinical populations (type 2 diabetes, overweight/obesity, impaired glucose tolerance)
Caveats: The evidence includes meta-analyses with high heterogeneity (I² > 80%), and the small effect size may limit clinical relevance. Two studies in hemodialysis patients and type 2 diabetes patients showed neutral findings, suggesting the effect may not extend to all subgroups. Most studies focused on standard L-carnitine; one neutral study used acetyl-L-carnitine, hinting that form may influence outcomes. Publication bias is not strongly suggested, but the evidence base is moderately sized (6 studies) with mixed signals across populations.
Generated Jun 12, 2026