L-Carnitine and Reduced Fasting Blood Glucose Levels

Research synthesisModerate evidenceSmall effect3 studies · 3 beneficial · 0 neutral · 0 harmful

Across 3 studies, all reported beneficial small-sized effects of L-carnitine supplementation on reducing fasting blood glucose levels. Studies included populations with PCOS, diabetes, and impaired glucose tolerance, with a median study duration of 42 days (based on one study).

Studied populations: adults with PCOS, diabetes, or impaired glucose tolerance

Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Evidence base is small (only 3 studies) — conclusions should be considered preliminary.

Generated May 13, 2026

Doses used in studies

L-Carnitine · mg/day: 3,000 (median 3,000, IQR 3,000–3,000) — 1 study

Time to effect

Median: 6 weeks · IQR 6 weeks–6 weeks · Range 6 weeks–6 weeks — Reported in 1 of 3 studies

3 of 3 papersPopulation:

Adding L-carnitine to antagonist ovarian stimulation doesn't improve the outcomes of IVF/ ICSI cycle in patients with polycystic ovarian syndrome: a double-blind randomized clinical trial.
- 2024-01-09
- RCT · n = 110
- Journal of ovarian research 17(1)
- - Maryam Hafezi
  - Arezoo Arabipoor
  - Firouzeh Ghaffari
  - Samira Vesali
  - Maryam Zareei
  - Zahra Hajinaghibali Hessari
- PubMed: 38191449
- DOI: 10.1186/s13048-023-01319-7
13 Insights on
- Reduced Fasting Blood Glucose Levels
- High evidence
- Large Human Trial
- Clinical
serum levels of fasting blood sugar (P = 0.021) … have significantly decreased in women after consuming L-carnitine supplementation
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
3000 mg/day (3 tablets daily of 1000 mg L-carnitine)
Effects of L-carnitine supplementation on glucolipid metabolism: a systematic review and meta-analysis.
- 2023
- Meta-Analysis
- Food & function 14(5)
- - Yanfei Li
  - Yuchen Xie
  - Chensheng Qiu
  - Bowen Yu
  - Fangzheng Yang
  - Yuanchao Cheng
  - Weizhen Zhong
  - Junhua Yuan
- PubMed: 36815696
- DOI: 10.1039/d2fo02930h
9 Insights on
- Reduced Fasting Blood Glucose Levels
- High evidence
- Rigorous Journal
- Adults
significant effects of L-carnitine on FBG (MD = -4.94 mg dL-1, 95% CI: -7.07 to -2.82)
Effect
Beneficial
Effect size
Small
Significant
Yes
The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis.
- 2024-07-31
- Review · n = 2,900
- Diabetology & metabolic syndrome 16(1)
- - Rezvan Gheysari
  - Mahlagha Nikbaf-Shandiz
  - Amir Mehdi Hosseini
  - Niloufar Rasaei
  - Shabnam Hosseini
  - Hossein Bahari
  - Omid Asbaghi
  - Samira Rastgoo
  - Kian Goudarzi
  - Farideh Shiraseb
  - Reza Behmadi
- PubMed: 39085907
- DOI: 10.1186/s13098-024-01415-8
11 Insights on
- Reduced Fasting Blood Glucose Levels
- High evidence
L-carnitine supplementation had a significant effect on FBG (WMD = - 6.24 mg/dl, p = 0.001)
Effect
Beneficial
Effect size
Small
Significant
Yes

L-Carnitine and Reduced Fasting Blood Glucose Levels

Adding L-carnitine to antagonist ovarian stimulation doesn't improve the outcomes of IVF/ ICSI cycle in patients with polycystic ovarian syndrome: a double-blind randomized clinical trial.

Effects of L-carnitine supplementation on glucolipid metabolism: a systematic review and meta-analysis.

The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis.