l-carnitine plays a fundamental biological role in the metabolism of lipids and may positively affect blood pressure by decreasing insulin resistance, although the latter remains less clear. We aimed to assess the effects of l-carnitine supplementation on systolic (SBP) and diastolic blood pressure (DBP). A search was conducted using databases of EMBASE, PubMed, Scopus, Cochrane Library, and ISI web of Science from inception to February 2019 without limitations in language. A meta-analysis was conducted on a total of ten eligible randomized controlled trials using a random-effects model to estimate the pooled effect sizes of l-carnitine supplementation on SBP and DBP levels. Results were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). l-carnitine supplementation decreased DBP (−1.162 mmHg, 95% CI: −2.020, −0.303, p = 0.008) without changing SBP levels (−0.085 mmHg, 95% CI: −1.455, 1.285, p = 0.903). Results of the subgroup analyses revealed l-carnitine supplementation decreased DBP levels in participants with overweight and obesity (−1.232 mmHg, 95% CI: −2.297, −0.167, p = 0.023) and with doses of <2 g/d (−1.639 mmHg, 95% CI: −3.038, −0.240, p = 0.022). No evidence of publication bias was observed about the effects of l-carnitine supplementation on SBP (p = 0.307) and DBP (p = 0.729), as evidenced by the results of the Egger’s test. In conclusion, l-carnitine supplementation decreased DBP without affecting SBP levels. Research is required to determine the molecular mechanism underlying the relationship between of l-carnitine on blood pressure.
Subscribe to Journal
Get full journal access for 1 year
only $33.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Rajasekar P, Palanisamy N, Anuradha C. Increase in nitric oxide and reductions in blood pressure, protein kinase C β II and oxidative stress by l-carnitine: a study in the fructose-fed hypertensive rat. Clin Exp Hypertens. 2007;29:517–30.
Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL,Jr. et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. Jama. 2003;289:2560–72.
MacMahon S, Peto R, Cutler J, Collins R, Sorlie P, Neaton J, et al. Blood pressure, stroke, and coronary heart disease. Part 1, Prolonged differences in blood pressure: prospective observational studies corrected for the regression dilution bias. Lancet. 1990;335:765–74.
Sarnak MJ, Levey AS, Schoolwerth AC, Coresh J, Culleton B, Hamm LL, et al. Kidney disease as a risk factor for development of cardiovascular disease: a statement from the American Heart Association Councils on Kidney in Cardiovascular Disease, High Blood Pressure Research, Clinical Cardiology, and Epidemiology and Prevention. Hypertension. 2003;42:1050–65.
Fagard RH. Resistant hypertension. Heart (British Cardiac Society). 2012;98:254–61.
Serban C, Sahebkar A, Ursoniu S, Andrica F, Banach M. Effect of sour tea (Hibiscus sabdariffa L.) on arterial hypertension: a systematic review and meta-analysis of randomized controlled trials. J Hypertens. 2015;33:1119–27.
Serban MC, Sahebkar A, Zanchetti A, Mikhailidis DP, Howard G, Antal D, et al. Effects of quercetin on blood pressure: a systematic review and meta‐analysis of randomized controlled trials. J Am Heart Assoc. 2016;5:e002713.
Woodworth JC, Minton JE, Tokach MD, Nelssen JL, Goodband RD, Dritz SS, et al. Dietary l-carnitine increases plasma leptin concentrations of gestating sows fed one meal per day. Domest Anim Endocrinol. 2004;26:1–9.
Broad E, Bolger C, Galloway S. Dietary carnitine intake and carnitine status in endurance‐trained males. Nutr Diet. 2006;63:148–54.
Rebouche CJ. Carnitine function and requirements during the life cycle. FASEB J. 1992;6:3379–86.
Stanley CA. Carnitine deficiency disorders in children. Ann NY Acad Sci. 2004;1033:42–51.
Zammit VA. Carnitine acyltransferases: functional significance of subcellular distribution and membrane topology. Prog Lipid Res. 1999;38:199–224.
Xu Y, Jiang W, Chen G, Zhu W, Ding W, Ge Z, et al. L-carnitine treatment of insulin resistance: a systematic review and meta-analysis. Adv Clin Exp Med. 2017;26:333–8.
Sowers JR. Insulin resistance and hypertension. Mol Cell Endocrinol. 1990;74:C87–9.
Duranay M, Akay H, Yilmaz FM, Şeneş M, Tekeli N, Yücel D. Effects of L-carnitine infusions on inflammatory and nutritional markers in haemodialysis patients. Nephrol Dial Transplant. 2006;21:3211–4.
El-sheikh HM, El-Haggar SM, Elbedewy TA. Comparative study to evaluate the effect of l-carnitine plus glimepiride versus glimepiride alone on insulin resistance in type 2 diabetic patients. Diabetes Metab Syndr: Clin Res Rev. 2019;13:167–73.
Higuchi T, Abe M, Yamazaki T, Mizuno M, Okawa E, Ando H. et al. Effects of levocarnitine on brachial-ankle pulse wave velocity in hemodialysis patients: a randomized controlled trial. Nutrients. 2014;6:5992–6004.
Higuchi T, Abe M, Yamazaki T, Okawa E, Ando H, Hotta S, et al. Levocarnitine improves cardiac function in hemodialysis patients with left ventricular hypertrophy: a randomized controlled trial. Am J Kidney Dis. 2016;67:260–70.
Mahdavi AM, Mahdavi R, Kolahi S, Attari VE. Cardiometabolic responses to L-carnitine in obese women with knee osteoarthritis: a randomized, double-blind, placebo-controlled pilot study. Prog Nutr. 2018;20(1-S):337–44.
Malaguarnera M, Cammalleri L, Gargante MP, Vacante M, Colonna V, Motta M. l-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial. Am J Clin Nutr. 2007;86:1738–44.
Maruyama T, Higuchi T, Yamazaki T, Okawa E, Ando H, Oikawa O, et al. Levocarnitine injections decrease the need for erythropoiesis-stimulating agents in hemodialysis patients with renal anemia. Cardiorenal Med. 2017;7:188–97.
Sakurabayashi T, Miyazaki S, Yuasa Y, Sakai S, Suzuki M, Takahashi S. et al. L-carnitine supplementation decreases the left ventricular mass in patients undergoing hemodialysis. Circ J. 2008;72:926–31.
Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JP. et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med. 2009;6:e1000100.
Higgins JP, Green S. Cochrane handbook for systematic reviews of interventions. New York: John Wiley & Sons; 2011.
Borenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis. New York: John Wiley & Sons; 2011.
Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ: Br Med J. 2003;327:557.
Egger M, Smith GD, Schneider M, Minder C. Bias in meta-analysis detected by a simple, graphical test. Bmj . 1997;315:629–34.
Parvanova A, Trillini M, Podestà MA, Iliev IP, Aparicio C, Perna A, et al. Blood pressure and metabolic effects of acetyl-l-carnitine in type 2 diabetes: DIABASI randomized controlled trial. J Endocr Soc. 2018;2:420–36.
Santo SS, Sergio N, Giuseppe M, Margherita F, Gea OC, Roberto F, et al. Effect of PLC on functional parameters and oxidative profile in type 2 diabetes-associated PAD. Diabetes Res Clin Pract. 2006;72:231–7.
American Diabetes A. Standards of medical care in diabetes—2013. Diabetes Care. 2013;36(Suppl 1):S11–S66.
Brunstrom M, Carlberg B. Effect of antihypertensive treatment at different blood pressure levels in patients with diabetes mellitus: systematic review and meta-analyses. BMJ (Clin Res Ed). 2016;352:i717.
Lipworth B, Skinner D, Devereux G, Thomas V, Ling Zhi Jie J, Martin J, et al. Underuse of beta-blockers in heart failure and chronic obstructive pulmonary disease. Heart (British Cariac Society). 2016;102:1909–14.
Kolkhof P, Nowack C, Eitner F. Nonsteroidal antagonists of the mineralocorticoid receptor. Curr Opin Nephrol Hypertens. 2015;24:417–24.
Wang ZY, Liu YY, Liu GH, Lu HB, Mao CY. l-Carnitine and heart disease. Life Sci. 2018;194:88–97.
Sidorenkov G, Navis G. Safety of ACE inhibitor therapies in patients with chronic kidney disease. Expert Opin Drug Saf. 2014;13:1383–95.
McMackin CJ, Widlansky ME, Hamburg NM, Huang AL, Weller S, Holbrook M, et al. Effect of combined treatment with alpha-Lipoic acid and acetyl-L-carnitine on vascular function and blood pressure in patients with coronary artery disease. J Clin Hypertension. 2007;9:249–55.
Poorabbas A, Fallah F, Bagdadchi J, Mahdavi R, Aliasgarzadeh A, Asadi Y, et al. Determination of free L-carnitine levels in type II diabetic women with and without complications. Eur J Clin Nutr. 2007;61:892–5.
Ylitalo K, Vanttinen T, Halmesmaki E, Tyni T. Serious pregnancy complications in a patient with previously undiagnosed carnitine palmitoyltransferase 1 deficiency. Am J Obstet Gynecol. 2005;192:2060–2.
Thiele IG, Niezen-Koning KE, van Gennip AH, Aarnoudse JG. Increased plasma carnitine concentrations in preeclampsia. Obstet Gynecol. 2004;103(5 Pt 1):876–80.
Hart EC, Joyner MJ, Wallin BG, Johnson CP, Curry TB, Eisenach JH. et al. Age-related differences in the sympathetic-hemodynamic balance in men. Hypertension. 2009;54:127–33.
Gonzalez-Ortiz M, Hernandez-Gonzalez SO, Hernandez-Salazar E, Martinez-Abundis E. Effect of oral L-carnitine administration on insulin sensitivity and lipid profile in type 2 diabetes mellitus patients. Ann Nutr Metab. 2008;52:335–8.
Molfino A, Cascino A, Conte C, Ramaccini C, Rossi Fanelli F, Laviano A. Caloric restriction and L-carnitine administration improves insulin sensitivity in patients with impaired glucose metabolism. JPEN J Parenter Enter Nutr. 2010;34:295–9.
Wu X, Han T, Gao J, Zhang Y, Zhao S, Sun R, et al. Association of serum calcium and insulin resistance with hypertension risk: a prospective population-based study. J Am Heart Assoc. 2019;8:e009585.
Guo J, Liu G, Guo G. Association of insulin resistance and autonomic tone in patients with pregnancy-induced hypertension. Clin Exp Hypertens. 2018;40:476–80.
Song X, Qu H, Yang Z, Rong J, Cai W, Zhou H. Efficacy and safety of l-carnitine treatment for chronic heart failure: a meta-analysis of randomized controlled trials. BioMed Res Int. 2017;2017:6274854.
Katz AM. Is the failing heart energy depleted?. Cardiol Clin. 1998;16:633–44.
Khalatbari-Soltani S, Tabibi H. Inflammation and L-carnitine therapy in hemodialysis patients: a review. Clin Exp Nephrol. 2015;19:331–5.
Mohammadi M, Hajhossein Talasaz A, Alidoosti M. Preventive effect of l-carnitine and its derivatives on endothelial dysfunction and platelet aggregation. Clin Nutr ESPEN. 2016;15:1–10.
Lee BJ, Lin JS, Lin YC, Lin PT. Effects of L-carnitine supplementation on lipid profiles in patients with coronary artery disease. Lipids Health Dis. 2016;15:107.
Malek Mahdavi A, Mahdavi R, Kolahi S, Zemestani M, Vatankhah AM. L-Carnitine supplementation improved clinical status without changing oxidative stress and lipid profile in women with knee osteoarthritis. Nutr Res. 2015;35:707–15.
Nazary-vannani A, Ghaedi E, Mousavi SM, Teymouri A, Rahmani J, Varkaneh HK. The effect of L-carnitine supplementation on serum leptin concentrations: a systematic review and meta-analysis of randomized controlled trials. New York: Springer; 2018.
Gokdemir MT, Gokdemir GS, Tas M. The association between mean platelet volume and inflammation in geriatric patients with emergency hypertension. Turk J Emerg Med. 2019;19:16–20.
Chen J, Bundy JD, Hamm LL, Hsu CY, Lash J, Miller ER, 3rd, et al. Inflammation and apparent treatment-resistant hypertension in patients with chronic kidney disease. Hypertension. 2019;73:785–93.
Choudhury KN, Mainuddin AK, Wahiduzzaman M, Islam SM. Serum lipid profile and its association with hypertension in Bangladesh. Vasc Health Risk Manag. 2014;10:327–32.
Adamu UG, Okuku GA, Oladele CO, Abdullahi A, Oduh JI, Fasae AJ. Serum lipid profile and correlates in newly presenting Nigerians with arterial hypertension. Vasc Health Risk Manag. 2013;9:763–8.
Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT. et al. Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013;19:576–85.
Tang WH, Wang Z, Levison BS, Koeth RA, Britt EB, Fu X, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. New Engl J Med. 2013;368:1575–84.
Chen H, Li J, Li N, Liu H, Tang J. Increased circulating trimethylamine N-oxide plays a contributory role in the development of endothelial dysfunction and hypertension in the RUPP rat model of preeclampsia. Hypertens Pregnancy. 2019;38:96–104.
Hathcock JN, Shao A. Risk assessment for carnitine. Regul Toxicol Pharmacol. 2006;46:23–8.
Villani RG, Gannon J, Self M, Rich PA. L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. Int J Sport Nutr Exerc Metab. 2000;10:199–207.
Conflict of interest
The authors declare that they have no conflict of interest.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Askarpour, M., Hadi, A., Dehghani Kari Bozorg, A. et al. Effects of l-carnitine supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials. J Hum Hypertens 33, 725–734 (2019). https://doi.org/10.1038/s41371-019-0248-1
Quantitative efficacy of L-carnitine supplementation on glycemic control in type 2 diabetes mellitus patients
Expert Review of Clinical Pharmacology (2021)
Hellenic Journal of Cardiology (2020)
L-Carnitine supplementation reduces biomarkers of inflammatory and oxidative stress in patients with coronary artery disease: a randomised controlled trial
Archives of Physiology and Biochemistry (2020)
Rational Pharmacotherapy in Cardiology (2020)
L-Carnitine’s Effect on the Biomarkers of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials