Peptide Price Finder

Home · Research · GLP-1 & metabolic

L-Carnitine research

What published studies found for L-Carnitine: 8 papers, 7 in humans, with sample sizes and key results, plus 202 registered clinical trials.

A
Strong human evidence
Why: Several meta-analyses of RCTs (37-43 trials, over 2,000 people) agree on a small extra weight loss of about 1 kg, mainly in overweight adults.

Several meta-analyses of randomized human trials agree that oral L-carnitine produces a small extra weight loss (roughly 1 kg on average), mainly in people with overweight or obesity, with no consistent effect on waist size or body-fat percentage. Trials are heterogeneous and most used oral supplements, not injections.

✓ 6 positive✗ 1 negative~ 1 mixed

Abstracts describe oral L-carnitine as generally well tolerated; long-term cardiovascular relevance of the TMAO rise is unknown, and injectable L-carnitine for weight loss was not studied in these papers.

US compounding: FDA-approved drug. FDA-approved as levocarnitine (Carnitor). Status for every peptide.

Browse and filter these papersL-Carnitine prices and vendors

Reported side effects

Registered clinical trials

202 trials of L-Carnitine on ClinicalTrials.gov: 24 active, 113 completed, 20 with posted results. Registered trials include ones that haven't published yet.

TrialStatusPhasePeopleSponsor
Studying the Effect of Levocarnitine in Protecting the Liver From Chemotherapy for Leukemia or LymphomaNCT05602194 · started 2023-08-24Active, not recruitingPhase 3440Children's Oncology Group
Trial on the Biological and Clinical Effects of Acetyl-L-carnitine in ALSNCT06126315 · started 2025-03-26RecruitingPhase 2, Phase 3246Mario Negri Institute for Pharmacological Research
Using Gut Microbial Gbu Gene Testing to Estimate Host TMAO Production CapacityNCT05980884 · started 2023-07-24Active, not recruiting–230National Taiwan University Hospital
Effect of L-carnitine Supplementation on Phenylalanine and Brain-derived Neurotrophic Factor Levels in Infants and Children With PhenylketonuriaNCT06901323 · started 2025-02-01Active, not recruitingPhase 4176Mansoura University
Effect of L-Carnitine Supplementation in Preterm NeonatesNCT07437391 · started 2026-01-01Recruiting–160Muhammad Aamir Latif
Enteral Nutrition With L-Carnitine for Cachexia in Non-Small Cell Lung CancerNCT07035444 · started 2025-06-30Not yet recruiting–126Daping Hospital and the Research Institute of Surgery of the Third Military Medical University
CARNIVAL Study: Gut Flora Dependent Metabolism of Dietary CARNItine and Phosphatidylcholine and cardioVAscuLar DiseaseNCT01731236 · started 2011-02-11Active, not recruitingEarly phase 1100The Cleveland Clinic
Levocarnitine for Reducing ESA Requirements in Hemodialysis Patients With Renal AnemiaNCT07160452 · started 2025-09-15Not yet recruitingPhase 494Shaikh Zayed Hospital, Lahore
Effect of Magnesium and Levocarnitine on Metabolic and Clinical Outcomes in Women With Polycystic Ovarian Syndrome (PCOS)NCT07298564 · started 2026-01-30Recruiting–84Behnood Abbasi
Peritoneal Ultrafiltration in Cardio Renal Syndrome.NCT03994874 · started 2025-04-16RecruitingPhase 1, Phase 284Iperboreal Pharma Srl
Effect of L-Carnitine on Biomarkers of Myocardial Reperfusion Injury in Patients With STEMINCT06564909 · started 2025-06-01Active, not recruitingPhase 276Ain Shams University
Effect of Levocarnitine Plus Myoinositol Versus Myoinositol Alone on Hormonal and Insulin Resistance in PCOS WomenNCT07266259 · started 2025-09-19Recruiting–72Mst.Sumyara Khatun

All 202 L-Carnitine trials, with countries and recruiting status

Meta-analyses & systematic reviews

✓ Positivemeta-analysisInt J Vitam Nutr Res · 2025

The Effect of the L-Carnitine Supplementation on Obesity Indices: An Umbrella Meta-Analysis.

n = 16,352 humansUmbrella meta-analysis (random-effects)Interventions of 8 to 30 weeks

Umbrella meta-analysis of 8 meta-analyses (16,352 participants): L-carnitine reduced body weight (effect size -1.11), BMI and waist circumference, though heterogeneity was high.

Key resultL-carnitine decreased weight (ES = -1.11; 95% CI -1.90, -0.33, p = 0.005), BMI (ES = -0.33; p = 0.026) and WC (ES = -1.34; p < 0.001)
Studied
Participants in trials of L-carnitine supplementation pooled by eight meta-analyses
Compared with
Placebo or control
Main outcome
Body weight, BMI and waist circumference
Sample
8 meta-analyses, 16,352 participants
Authors' conclusion
L-carnitine supplementation can manage weight, BMI and waist circumference reduction and might help treat obesity.
Limitations
High heterogeneity (I2 = 90.6% for weight); concerns L-carnitine alone, one possible ingredient of lipotropic blends.
PubMed 40298161DOI
✓ Positivemeta-analysisClin Nutr ESPEN · 2020

Effects of l-carnitine supplementation on weight loss and body composition: A systematic review and meta-analysis of 37 randomized controlled clinical trials with dose-response analysis.

n = 2,292 humansSystematic review and meta-analysis of RCTs with dose-response analysis

Meta-analysis of 37 RCTs (2,292 adults): L-carnitine lowered body weight by 1.21 kg and fat mass by 2.08 kg versus control; no significant effect on waist circumference or body-fat percent.

Key resultBody weight WMD -1.21 kg (95% CI -1.73, -0.68; P < 0.001); BMI WMD -0.24 kg/m2 (P = 0.001); fat mass WMD -2.08 kg (P = 0.003); no significant effect on waist circumference or body fat percent
Studied
Participants in 37 randomized controlled trials of l-carnitine supplementation
Compared with
Control
Main outcome
Body weight, BMI, fat mass, waist circumference, body fat percent
Sample
37 RCTs, 2292 participants
Authors' conclusion
L-carnitine provides a modest reducing effect on body weight, BMI and fat mass, especially among adults with overweight/obesity; 2000 mg/day gave the maximum effect on weight.
Limitations
Only body weight effect confirmed in high-quality RCTs alone.
PubMed 32359762DOI
✓ Positivemeta-analysisClin Ther · 2024

The Effects of L-Carnitine Supplementation on Weight Loss, Glycemic Control, and Cardiovascular Risk Factors in Patients With Type 2 Diabetes: A Systematic Review and Dose-response Meta-Analysis of Randomized Controlled Trials.

n = 2,041 humansSystematic review and dose-response meta-analysis of RCTs (GRADE rated)

Meta-analysis of 21 RCTs in 2,041 people with type 2 diabetes: small reductions in BMI, HbA1c, LDL cholesterol and fasting glucose; authors urge caution because of very high heterogeneity.

Key resultPer 1 g/d: BMI MD -0.37 kg/m2 (95% CI -0.59, -0.15); HbA1c MD -0.16% (95% CI -0.32, -0.01); LDL-C MD -0.11 mmol/L (95% CI -0.16, -0.05)
Studied
Adults with type 2 diabetes in 21 randomized trials
Compared with
Control
Main outcome
BMI, HbA1c, LDL cholesterol and other cardiometabolic markers
Sample
21 RCTs, 2041 patients with type 2 diabetes
Authors' conclusion
L-carnitine produced a small reduction in serum lipids and plasma glucose in type 2 diabetes, but given high heterogeneity the results should be interpreted very cautiously.
Limitations
High statistical heterogeneity (I2 91 to 94%).
PubMed 38594107DOI
✓ Positivemeta-analysisObes Rev · 2016

The effect of (L-)carnitine on weight loss in adults: a systematic review and meta-analysis of randomized controlled trials.

n = 911 humansSystematic review and meta-analysis of RCTs (random effects)

Meta-analysis of 9 RCTs (911 adults): carnitine groups lost 1.33 kg more than controls, but the effect shrank the longer supplementation continued.

Key resultWeight MD -1.33 kg (95% CI -2.09 to -0.57); BMI MD -0.47 kg/m2 (95% CI -0.88 to -0.05)
Studied
Adults in nine randomized controlled trials of carnitine
Compared with
Control group
Main outcome
Weight loss and BMI
Sample
9 RCTs, total n = 911
Authors' conclusion
Carnitine resulted in weight loss; the magnitude of weight loss decreased significantly over time of consumption (p = 0.002).
Limitations
Only nine trials pooled.
PubMed 27335245DOI
✓ Positivemeta-analysisPharmacol Res · 2020

Beneficial effects of l-carnitine supplementation for weight management in overweight and obese adults: An updated systematic review and dose-response meta-analysis of randomized controlled trials.

43 RCTsSystematic review and dose-response meta-analysis of RCTs

Meta-analysis of 43 RCTs: weight fell 1.13 kg and BMI 0.36 kg/m2 versus control, with effects seen only in overweight/obese adults; body-fat percentage and waist circumference did not change significantly.

Key resultWeight WMD -1.129 kg (95% CI -1.590, -0.669); BMI WMD -0.359 kg/m2 (95% CI -0.552, -0.167); fat mass WMD -1.158 kg; no change in body fat percentage or waist circumference
Studied
Participants in 43 randomized controlled trials of l-carnitine supplementation
Compared with
Control
Main outcome
Weight, BMI, fat mass, body fat percentage, waist circumference
Authors' conclusion
L-carnitine might have positive effects on body weight and BMI, especially in overweight and obese subjects; no anthropometric change in hemodialysis patients.
Limitations
High heterogeneity for BMI (I2 85.2) and body fat percentage (I2 98.2).
PubMed 31743774DOI
~ Mixedsystematic reviewJ Int Soc Sports Nutr · 2020

The bright and the dark sides of L-carnitine supplementation: a systematic review.

11 studies in healthy humansSystematic review12 or 24 weeks

Review of 11 studies of 12-24 weeks of oral L-carnitine in healthy people: some gains in muscle carnitine and function in specific groups, but supplementation raised fasting plasma TMAO, a compound suspected to be pro-atherogenic.

Studied
Healthy humans supplemented orally with L-carnitine for at least 12 weeks (1 to 4 g/day)
Main outcome
Metabolism and metabolic modifications
Authors' conclusion
Prolonged LC supplementation may affect physical performance in specific conditions, but raises fasting plasma TMAO, a supposedly pro-atherogenic compound; long-term cardiovascular studies are needed.
Limitations
Small set of studies; long-term cardiovascular effects unstudied.
PubMed 32958033DOIFree full text
Fig. 2: The association between LC supplementation and the regulation of metabolic pathways involved in muscle protein balance. L-carnitine (LC); in
Fig. 2. From PMC7507632, CC BY (terms); resized.

Human studies

✗ Negativehuman RCTJ Nutr · 2024

Effects of L-Carnitine Supplementation on the Rate of Weight Gain and Biomarkers of Environmental Enteric Dysfunction in Children with Severe Acute Malnutrition: A Double-Blind Randomized Controlled Clinical Trial.

n = 98 humansDouble-blind placebo-controlled randomized clinical trial15 days

Double-blind RCT in 98 children with severe acute malnutrition: L-carnitine syrup did not change rate of weight gain or gut-dysfunction biomarkers versus placebo.

Key resultRate of weight gain 2.09 ± 2.23 vs 2.07 ± 2.70 (P = 0.973) for L-carnitine vs placebo
Studied
Children aged 9-24 months with severe acute malnutrition, Dhaka, Bangladesh
Compared with
Placebo
Main outcome
Rate of weight gain; enteric dysfunction biomarkers
Sample
98 children with severe acute malnutrition
Authors' conclusion
L-carnitine (100 mg/kg/d) had no additional effect on severe acute malnutrition; longer trials, possibly with other combinations, are recommended.
Limitations
Short supplementation (15 days).
PubMed 38331348DOI

Reviews

✓ PositivereviewRegul Toxicol Pharmacol · 2006

Risk assessment for carnitine.

No new dataRisk assessment review

Safety risk assessment of supplementation trials: found strong evidence of safety for chronic intake at commonly studied levels, with insufficient data to judge long-term safety at higher intakes.

Main outcome
Safety of carnitine supplementation
Authors' conclusion
Using the observed safe level method, evidence of safety is strong up to 2000 mg/day l-carnitine for chronic supplementation; data above that are insufficient for a confident conclusion of long-term safety.
PubMed 16901595DOI

Verdicts are judged on each paper's own main outcome; grades run from A (strong human evidence) to D (little or none). Details are read from the abstracts, and figures are reproduced only from openly licensed full texts. Not medical advice.