Important limitations
- Individual claims and source links have not yet completed editorial verification.
- Evidence level, applicable study model, formulation, route and population remain unassigned.
L Carnitine
L-carnitine (levocarnitine) is a small quaternary ammonium compound that the body makes from lysine and methionine and also takes in from meat and dairy.
Reported protocols for L Carnitine
What published studies and recent community write-ups report about amounts, timing and course length. 5 clinical and 3 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.
| Context | Dose | Frequency | Route | Course | Source |
|---|---|---|---|---|---|
| Clinical5 rows | |||||
| FDA label, intravenous use in metabolic disordersPatients with inborn errors of metabolism and secondary carnitine deficiency | 50 mg/kg per dose (highest reported 300 mg/kg) | Every 3 or 4 hours, never less often than every 6 hours; a loading dose is often followed by the same amount spread over the next 24 hours | Slow 2-3 minute intravenous bolus or infusion | Continued as therapy requires, with weekly and monthly monitoringNone described | DailyMed, National Library of Medicine2023 |
| The label asks for a plasma carnitine level before parenteral therapy starts and for free carnitine to be kept between 35 and 60 micromol/L, with blood chemistry and vital signs checked weekly and monthly. Carnitor Injection is labelled for intravenous use only; it carries no intramuscular or subcutaneous dosing. | |||||
| FDA label, intravenous use in dialysis patientsAdults with end-stage renal disease on maintenance hemodialysis | 10-20 mg/kg dry body weight to start; may be lowered to 5 mg/kg from week 3 or 4 | After each dialysis session (three times weekly in the 9-week label study at 20 mg/kg) | Slow 2-3 minute bolus into the venous return line of the dialysis circuit | Ongoing; dose adjusted to pre-dialysis trough levelsNone described | DailyMed, National Library of Medicine2023 |
| Therapy is started when the pre-dialysis plasma level falls below the normal 40-50 micromol/L range, and the dose is adjusted to trough levels rather than to symptoms. In the label's 9-week study of 12 patients, pre-dialysis levels of about 20 micromol/L rose to about 190 micromol/L after 8 weeks of 20 mg/kg three times a week, well above the 40-50 micromol/L threshold, which is why the label allows dose reductions from the third week. | |||||
| FDA label, oral tablets and solutionAdults with primary or secondary carnitine deficiency | 990 mg (three 330 mg tablets); or 1-3 g per day of oral solution for a 50 kg adult, starting at 1 g per day | Two or three times daily (tablets); solution spaced every 3-4 hours with or after meals | Oral | Ongoing, with periodic blood chemistry and plasma carnitine checksNone described | DailyMed, National Library of Medicine2024 |
| The oral label starts the solution at 1 g per day and raises it slowly while tolerance and response are assessed, warning that higher doses need a clear biochemical reason. Oral carnitine is poorly absorbed compared with the intravenous product, which is the usual argument made for injectable use. | |||||
| Meta-analysis of 37 randomized trials for weight loss2,292 adults across 37 randomized controlled trials, mostly with overweight or obesity | Varied by trial; the dose-response curve peaked at 2,000 mg per day | Daily | Oral in the pooled trials | Trial lengths varied; the review searched studies to January 2019Not applicable | Clinical Nutrition ESPEN (PubMed)2020 |
| Pooled weight change was 1.21 kg lower than control, BMI 0.24 kg/m2 lower and fat mass 2.08 kg lower, with no effect on waist circumference or body fat percentage; only the weight effect survived when the analysis was limited to high-quality trials. The dose-response relationship was non-linear, with no extra benefit above 2 g per day. | |||||
| Muscle carnitine loading trial with carbohydrate14 healthy men, mean age 26 | 2 g L-carnitine L-tartrate with 80 g carbohydrate per dose | Twice daily | Oral | 24 weeksNone | The Journal of Physiology (PubMed)2011 |
| Muscle total carnitine rose 21% only in the carnitine group and only after 24 weeks, with 55% less glycogen use during low-intensity cycling and 11% more work in a 30-minute performance test. The carbohydrate was there to raise insulin, which is what drives carnitine into muscle; the result does not show what happens with injected carnitine alone. | |||||
| Community-reported3 rows | |||||
| Telehealth body-composition protocol | 1,000-2,000 mg per injection | Two or three times per week, 30-60 minutes before a 30-45 minute aerobic session | Intramuscular (deltoid or outer thigh) or subcutaneous, rotating sites; more than 2 mL per intramuscular site described as avoided | 8-12 weeks4-week washout to recheck labs before any repeat | Community resource2025 |
| A telehealth site's 2025 guide pairs injections with a verified calorie deficit, resistance training and protein targets, and schedules plasma carnitine and liver enzymes at 6 weeks and a full panel with DEXA at 12 weeks. It states that no single accepted protocol exists for body composition and that these figures reflect clinic practice rather than trial dosing. | |||||
| Research-vial dosing guide | 200-600 mg for fat metabolism; 500-1,000 mg pre-workout | Three to five times per week; pre-workout doses 30-60 minutes before training | Intramuscular or subcutaneous; volumes above 3 mL split across two sites | OngoingNone; the guide says cycling is not needed | Community resource2026 |
| This 2026 guide works from a 600 mg per 10 mL vial (60 mg/mL), so a 200 mg dose is 3.3 mL and a full dose empties the vial across two or three sites. It describes injection-site pain as the main complaint, suggests warming the vial, and gives 28 days as the in-use limit after first puncture. | |||||
| Vendor listing for a 500 mg/mL vial | 1,000-2,000 mg per day (2-4 mL at 500 mg/mL) | Daily, pre-workout or fasted in the morning; 2,000 mg post-workout in its androgen-receptor protocol | Intramuscular preferred over subcutaneous at 2-4 mL volumes; 2 mL per site limit, daily site rotation | Not stated; a 10 mL vial covers 2.5-5 days at these dosesNone described | Community resource2026 |
| A steroid vendor's product page lists daily 1-2 g injections and frames them around anabolic-steroid cycles, citing resistance-training studies of oral L-carnitine L-tartrate on androgen receptor content. The daily doses are far above the 2-3 weekly injections most clinic protocols describe, and the page is a sales listing rather than a protocol with outcomes. | |||||
How a course is commonly described
- BaselineCommunity-reported
The telehealth protocol starts with plasma free and total carnitine, a metabolic panel, fasting glucose and insulin, lipids, thyroid tests and a blood count, and reserves injections for people whose fat loss has stalled despite a documented calorie deficit.
- Weeks 1-6Community-reported
1,000-2,000 mg is injected two or three times a week, 30-60 minutes before an aerobic session, alongside resistance training and a protein target. A plasma free carnitine check at week 6 is used to confirm loading, with liver enzymes drawn at the same time.
- Weeks 7-12Community-reported
Injections continue at the same rhythm to the end of an 8-12 week block, which closes with a repeat of the baseline panel and a DEXA scan. Guides built around smaller 200-600 mg doses describe no end point at all and treat use as continuous.
- WashoutCommunity-reported
The telehealth protocol pauses for 4 weeks after each block so that lab values can be reassessed before any repeat. No source gives a biological reason for the pause, and the research-vial guides say cycling is unnecessary.
- Clinical comparisonClinical
The only trial to show a rise in muscle carnitine took 24 weeks of twice-daily oral carnitine with carbohydrate, and nothing had changed at 12 weeks. The approved injectable is dosed continuously after every dialysis session or several times a day in metabolic crises, with no cycle structure.
- The 8-12 week block with a 4-week washout is a telehealth convention. No trial has tested intermittent intramuscular or subcutaneous L-carnitine for body composition, and the approved product is labelled for intravenous use only.
- Weight-loss evidence comes from oral trials and amounts to roughly 1 kg over the control group, with no added benefit above 2 g per day. Muscle carnitine rose in the one loading trial only after 24 weeks and only with carbohydrate to raise insulin.
- Vendor solutions range from 60 mg/mL to 500 mg/mL, so the same millilitre volume can deliver very different doses. Injection-site pain and large volumes are the most consistent complaints in community guides.
Sources for this section (7)
- CARNITOR (levocarnitine) Injection: Prescribing Information
- CARNITOR (levocarnitine) Tablets and Oral Solution: Prescribing Information
- 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
- Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans
Plus 3 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.
Overview
L-carnitine (levocarnitine) is a small quaternary ammonium compound that the body makes from lysine and methionine and also takes in from meat and dairy. Its job is to carry long-chain fatty acids across the inner mitochondrial membrane through the carnitine shuttle so they can be burned for energy, and skeletal and heart muscle hold most of the body's supply. Injectable levocarnitine is an FDA-approved prescription drug (Carnitor) for carnitine deficiency in inborn metabolic disorders and in dialysis patients, labelled for intravenous use only; the ready-to-use vials sold by research vendors for intramuscular or subcutaneous fat-loss and workout protocols are an off-label use with no label of their own. Human data on body weight come from oral trials, where meta-analyses find about 1 kg of extra weight loss, and one 24-week trial showed that muscle carnitine can be raised when carnitine is taken with carbohydrate.
What researchers are exploring
These themes organize the educational information currently available. Individual claims remain under source review and are not treatment claims.
- 1
Methionine
Sulfur-containing amino acid and precursor to S-adenosylmethionine (SAMe); important for methylation and detoxification. Molecular Formula: C 5 H 11 NO 2 Molecular Weight: 149.21 g/mol
- 2
Inositol
Involved in lipid signaling and studied for roles in mood regulation and metabolic health. Molecular Formula: C 6 H 12 O 6 Molecular Weight: 180.16 g/mol
- 3
CDP-Choline
Involved in acetylcholine synthesis and brain membrane repair. Molecular Formula: C 14 H 26 N 4 O 11 P 2 Molecular Weight: 488.32 g/mol
- 4
Vitamin B12 (Methylcobalamin)
Coenzyme in DNA synthesis, methylation, and red blood cell formation. Molecular Formula: C 63 H 91 CoN 13 O 14 P Molecular Weight: 1344.4 g/mol PubChem CID: 10898559
- 5
L-Carnitine
Facilitates the transport of long-chain fatty acids into mitochondria for β-oxidation. Molecular Formula: C 7 H 15 NO 3 Molecular Weight: 161.20 g/mol
- 6
L-Arginine
Precursor for nitric oxide synthesis; supports blood flow and vascular tone. Molecular Formula: C 6 H 14 N 4 O 2 Molecular Weight: 174.20 g/mol
What is known and what still needs verification
Available context is organized without assigning unsupported study models or evidence grades.
- Not graded
Methionine
Sulfur-containing amino acid and precursor to S-adenosylmethionine (SAMe); important for methylation and detoxification. Molecular Formula: C 5 H 11 NO 2 Molecular Weight: 149.21 g/mol
- Not graded
Inositol
Involved in lipid signaling and studied for roles in mood regulation and metabolic health. Molecular Formula: C 6 H 12 O 6 Molecular Weight: 180.16 g/mol
Chemistry identifiers
Sequence, synonyms and registry identifiers as recorded in PubChem, the National Library of Medicine's open chemistry database. Formula, mass and CAS number are summarized at the top of the page.
Also listed as
Levocarnitine, Carnitor, (R)-Carnitine, Vitamin BT, L-Carnitine inner salt, UNII 0G389FZZ9M, DrugBank DB00583, CHEBI:16347
InChIKey
PHIQHXFUZVPYII-ZCFIWIBFSA-N
IUPAC name
(3R)-3-hydroxy-4-(trimethylazaniumyl)butanoate
Limitations and unknowns
Sources
1 link carried over from the earlier page, awaiting verification.