Efficacy of l-carnitine supplementation for management of blood lipids: A systematic review and dose-response meta-analysis of randomized controlled trials

Nutr Metab Cardiovasc Dis. 2019 Nov;29(11):1151-1167. doi: 10.1016/j.numecd.2019.07.012. Epub 2019 Jul 24.


Background and aim: l-carnitine has an important role in fatty acid metabolism and could therefore act as an adjuvant agent in the improvement of dyslipidemia. The purpose of present systematic review and meta-analysis was to critically assess the efficacy of l-carnitine supplementation on lipid profiles.

Methods and results: We performed a systematic search of all available randomized controlled trials (RCTs) in the following databases: Scopus, PubMed, ISI Web of Science, The Cochrane Library. Mean difference (MD) of any effect was calculated using a random-effects model. In total, there were 55 eligible RCTs included with 58 arms, and meta-analysis revealed that l-carnitine supplementation significantly reduced total cholesterol (TC) (56 arms-MD: -8.53 mg/dl, 95% CI: -13.46, -3.6, I2: 93%), low-density lipoprotein-cholesterol (LDL-C) (47 arms-MD: -5.48 mg/dl, 95% CI: -8.49, -2.47, I2: 94.5) and triglyceride (TG) (56 arms-MD: -9.44 mg/dl, 95% CI: -16.02, -2.87, I2: 91.8). It also increased high density lipoprotein-cholesterol (HDL-C) (51 arms-MD:1.64 mg/dl, 95% CI:0.54, 2.75, I2: 92.2). l-carnitine supplementation reduced TC in non-linear fashion based on dosage (r = 21.11). Meta-regression analysis indicated a linear relationship between dose of l-carnitine and absolute change in TC (p = 0.029) and LDL-C (p = 0.013). Subgroup analyses showed that l-carnitine supplementation did not change TC, LDL-C and TG in patients under hemodialysis treatment. Intravenous l-carnitine and lower doses (>2 g/day) had no effect on TC, LDL-C and triglycerides.

Conclusion: l-carnitine supplementation at doses above 2 g/d has favorable effects on patients' lipid profiles, but is modulated on participant health and route of administration.

Keywords: Lipid profile; Meta-analysis; Systematic review; l-carnitine.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Carnitine / adverse effects
  • Carnitine / therapeutic use*
  • Dietary Supplements* / adverse effects
  • Dyslipidemias / blood
  • Dyslipidemias / diagnosis
  • Dyslipidemias / drug therapy*
  • Female
  • Humans
  • Hypolipidemic Agents / adverse effects
  • Hypolipidemic Agents / therapeutic use*
  • Lipids / blood*
  • Male
  • Middle Aged
  • Randomized Controlled Trials as Topic
  • Treatment Outcome
  • Young Adult


  • Biomarkers
  • Hypolipidemic Agents
  • Lipids
  • Carnitine