Effect of L-carnitine supplementation on fertility outcomes among patients with polycystic ovary syndrome: a systematic review and dose-response meta-analysis of randomized clinical trials

Abu-Zaid, Ahmed; Alghamdi, Ghadeer Adel; Alharbi, Alaa Saleh; Baradwan, Saeed; Saleh, Saleh A K; Adly, Heba M; Alzayed, Mooza M; Abuzaid, Mohammed; Sindi, Raghad; Alsabban, Mohannad; Alomar, Osama

doi:.0..

Review Article

DOI: https://doi.org/10.5468/ogs.24272 [Accepted]
Published online May 28, 2025.

Effect of L-carnitine supplementation on fertility outcomes among patients with polycystic ovary syndrome: a systematic review and dose-response meta-analysis of randomized clinical trials

Ahmed Abu-Zaid¹

, Ghadeer Adel Alghamdi², Alaa Saleh Alharbi², Saeed Baradwan³, Saleh A K Saleh⁴, Heba M Adly⁴, Mooza M Alzayed⁵, Mohammed Abuzaid⁶, Raghad Sindi⁷, Mohannad Alsabban³, Osama Alomar³

¹Department of Obstetrics and Gynecology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
²Department of Obstetrics and Gynecology, Care Hospital, Riyadh, Saudi Arabia
³Department of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia
⁴Department of Biochemistry, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
⁵College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
⁶Department of Obstetrics and Gynecology, Al Birk General Hospital, Al Birk, Saudi Arabia
⁷Faculty of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia

Correspondence: Ahmed Abu-Zaid,
Email: amabuzaid@alfaisal.edu

Received: 5 October 2024 • Revised: 5 January 2025 • Accepted: 23 April 2025

Abstract

This systematic review and meta-analysis of randomized controlled trials (RCTs) assessed the effect of L-carnitine (LC) supplementation on the fertility outcomes of patients with polycystic ovary syndrome (PCOS). Online databases (Scopus, Web of Science, Cochrane Library, EMBASE, and PubMed) were searched to identify eligible RCTs published until March 2024. A dose-response meta-analysis was performed using a random-effects model. Meta-regression was also performed to investigate the source of heterogeneity based on the LC dose and duration of treatment. The pooled analysis included eight RCTs with 1,046 participants. The LC-treated group had significantly increased chemical and clinical pregnancy rates, ovulation rate, progesterone levels, number of preovulatory follicles >17 mm in diameter, and endometrial thickness compared to the untreated groups. The meta-analysis model indicated that LC supplementation did not change the serum levels of estrogen and testosterone; however, the dose-response meta-analysis indicated that prolonged LC intake significantly increased estrogen levels. LC supplementation has significant effects on fertility outcomes of women with PCOS. Additional large-scale longer RCTs are required to confirm the findings of this study.

Key Words: L-carnitine, Polycystic ovary syndrome, Fertility, Ovulation