L-Carnitine

L-Carnitine is a quaternary ammonium compound required for the transport of fatty acids into mitochondria for beta-oxidation. It is NOT a peptide. FDA-approved for primary and secondary carnitine deficiency. Popular as a supplement for exercise performance.

PubMed results: 6,591 · Human studies: 3,095 · Animal studies: 5,456

Ranges reflect protocols studied in published research and animal-model extrapolation. Presented for research purposes only, not a recommendation or instruction for human use.

• Oral — standard range 500-2000 mg, 2-3 times daily

2-3 hours (high confidence)

• Mitochondrial fatty acid transport (Strong clinical): L-Carnitine is required for long-chain fatty acid transport into mitochondria for beta-oxidation; clinical use is established for primary and secondary carnitine deficiency.
• Dialysis-related carnitine depletion research (Moderate clinical): Clinical research in end-stage renal disease and hemodialysis populations has examined L-carnitine for effects on carnitine status and selected cardiovascular and muscle-related outcomes.
• Exercise metabolism research (Limited): Sports and metabolic studies have investigated L-carnitine for effects on fat oxidation and recovery markers, with mixed results depending on population and formulation.

• Gastrointestinal discomfort — Mild, Common. Nausea, cramping, diarrhea, and a fishy body odor have been reported in clinical and supplement contexts, especially at higher oral intakes.
• Fishy odor / trimethylamine-related odor — Mild, Uncommon. Metabolism to trimethylamine can produce a characteristic odor in some individuals studied in clinical and consumer research settings.

• Seizure disorders (research caution) (Clinical): Label and clinical literature note possible increased seizure activity in susceptible individuals; research protocols often exclude this population.
• Hypothyroidism under evaluation (Theoretical / Preclinical): Carnitine has been studied for interactions with thyroid hormone pathways; concurrent research use may confound endocrine assessment.

Lyophilized (powder): Refrigerated (2-8°C), Up to 24 months. Light sensitive: yes, store dark

Reconstituted (solution): Refrigerated (2-8°C), Per manufacturer; often multi-dose vials under refrigeration. Solvent: Sterile water or as supplied (injectable solutions are often ready-to-use)

• NCT05501899 — Use of Levocarnitine to Reduce Asparaginase Hepatotoxicity in Patients With Acute Lymphoblastic Leukemia (EARLY_PHASE1), status: RECRUITING. Indications: Acute Lymphoblastic Leukemia, Hepatotoxicity
• NCT00597909 — Efficacy and Safety Study of Ammonul® in Patients With Grade 3 or 4 Hepatic Encephalopathy (PHASE2), status: TERMINATED. Indications: Hepatic Encephalopathy
• NCT00927693 — Early Identification of Subclinical Atherosclerosis Using Non-Invasive Imaging Research (EISNER) (NA), status: COMPLETED. Indications: Atherosclerosis, Coronary Artery Disease
• NCT05948124 — Carnitine Supplementation in Pediatric Hemodialysis Patients (EARLY_PHASE1), status: UNKNOWN. Indications: Carnitine Deficiency Due to Hemodialysis
• NCT04086212 — Ultrafiltration Efficacy of a PD Solution Containing Icodextrin-Xylitol-Carnitine (PHASE2), status: WITHDRAWN. Indications: End Stage Renal Disease (ESRD)
• NCT06120400 — Cardiovascular Effects of a Healthy Dietary Pattern Containing Eggs (PHASE3), status: RECRUITING. Indications: Cardiovascular Diseases
• NCT04573153 — Metabolic Cofactor Supplementation and Hydroxychloroquine Combination in Covid-19 Patients (PHASE2 / PHASE3), status: TERMINATED. Indications: COVID-19
• NCT05905692 — Evaluation of the Impact of L- Carnitine in Intradialytic Hypotension in Pediatric Patients on Regular Hemodialysis (PHASE3), status: UNKNOWN. Indications: Intradialytic Hypotension
• NCT05801159 — [18F]FPIA PET-CT in Glioblastoma Multiforme (GBM), status: COMPLETED. Indications: Glioblastoma Multiforme of Brain
• NCT02635269 — Fat and Sugar Metabolism During Exercise in Patients With Metabolic Myopathy (NA), status: UNKNOWN. Indications: Metabolism, Inborn Errors, Lipid Metabolism, Inborn Errors, Carbohydrate Metabolism, Inborn Errors, Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency, Glycogenin-1 Deficiency (Glycogen Storage Disease Type XV), Carnitine Palmitoyl Transferase 2 Deficiency, VLCAD Deficiency, Medium-chain Acyl-CoA Dehydrogenase Deficiency, Multiple Acyl-CoA Dehydrogenase Deficiency, Carnitine Transporter Deficiency, Neutral Lipid Storage Disease, Glycogen Storage Disease Type II, Glycogen Storage Disease Type III, Glycogen Storage Disease Type IV, Glycogen Storage Disease Type V, Muscle Phosphofructokinase Deficiency, Phosphoglucomutase 1 Deficiency, Phosphoglycerate Mutase Deficiency, Phosphoglycerate Kinase Deficiency, Phosphorylase Kinase Deficiency, Beta Enolase Deficiency, Lactate Dehydrogenase Deficiency, Glycogen Synthase Deficiency
• NCT06175260 — Investigation on the Efficacy of Oral Carnitine Challenge Test Based on a Gut Microbiota Functional Test, status: COMPLETED. Indications: Dysbiosis, Healthy
• NCT04732429 — Study of HST5040 in Subjects With Propionic or Methylmalonic Acidemia (PHASE2), status: TERMINATED. Indications: Methylmalonic Acidemia, Propionic Acidemia
• NCT05539079 — A Prospective Long-term Observational Study in Patients With Monoclonal Gammopathy of Undetermined Significance, status: RECRUITING. Indications: MGUS
• NCT06023082 — A Single-Group Study to Examine the Efficacy of a Gut Health Supplement to Increase Metabolism, Improve Gut Health, and Support Weight Management (NA), status: COMPLETED. Indications: Gut Health, Metabolism, Weight Loss, Energy
• NCT00501956 — Intradialytic Parenteral Nutrition in Hemodialysis Patients (PHASE4), status: COMPLETED. Indications: Malnutrition, Complication of Hemodialysis
• NCT00755456 — Effect of an L-carnitine-containing Peritoneal Dialysis (PD) Solution on Insulin Sensitivity in Patients on Continuous Ambulatory Peritoneal Dialysis (CAPD) (PHASE2), status: COMPLETED. Indications: End Stage Renal Disease, Insulin Resistance
• NCT02645942 — L-carnitine for Reducing Cardio-metabolic Risk in Patients With Obstructive Sleep Apnea (NA), status: WITHDRAWN. Indications: Obstructive Sleep Apnea
• NCT02538146 — Effect of Acetyl-L-carnitine on Chronic Pancreatitis (EARLY_PHASE1), status: TERMINATED. Indications: Chronic Pancreatitis
• NCT06360302 — Plasma Biomarkers of Muscle Metabolism During Exercise to the Assessment of Insulin Resistance in CKD Dialysis Patients (NA), status: RECRUITING. Indications: Metabolic Syndrome, Dialysis; Complications
• NCT06368895 — Fecal Microbiota Transplantation by Oral Capsules for Hepatic Encephalopathy Treatment (PHASE1), status: RECRUITING. Indications: Hepatic Encephalopathy, Dysbiosis