L-Carnitine
Endogenous zwitterion required for mitochondrial long-chain fatty-acid transport and acyl-group buffering. Supplemental L-carnitine has low, saturable oral bioavailability, active tissue transport, saturable renal reabsorption, and a deep muscle pool; a single exponential is therefore only an effective plasma approximation. Meta-analyses suggest small average weight and recovery-marker effects in selected populations, not a general fat-burning or performance guarantee. Gut microbes can convert supplemental carnitine to trimethylamine and then TMAO.
Projected serum levels — 2k mg, once daily
Maintenance schedule: 2k mg once daily (oral).
Loading schedule: 6k mg on day 1, then 2k mg once daily — reaching therapeutic levels sooner.
Modeled steady state after ~7 days: peak ≈ 1.2k mg, trough ≈ 989 mg body load. Population-based estimate over 20 days for a 2k mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Amino Acid Derivative
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 2.5 days
- Common dose
- 2k mg
- Suggested maximum
- 6k mg/day
- Reference dose range
- 500–6k mg (single dose)
- Suggested cadence
- once daily
- Validated against
- 2k mg oral — Cmax 13.7 mg/L at 3.4 h
Research behind this entry
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Comparison of pharmacokinetics of L-carnitine, acetyl-L-carnitine and propionyl-L-carnitine after single oral administration of L-carnitine in healthy volunteers
Twelve healthy adults received 2 g liquid L-carnitine. Total plasma Cmax averaged 84.7 micromol/L at 3.4 hours, the reported terminal half-life was 60.3 hours, and urinary carnitine plus acylcarnitines demonstrated…
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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
Meta-analysis of 37 trials and 2,292 participants estimated a small 1.21 kg mean weight reduction, with smaller BMI and fat-mass changes but no significant waist or body-fat-percentage effect. Heterogeneous populations…
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L-Carnitine supplementation in recovery after exercise
Narrative review reports reduced soreness and biochemical damage markers in several supplementation studies, but it is not a new trial and three authors were employees of the ingredient manufacturer or its contractor.…
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Effect of acute and chronic oral L-carnitine supplementation on exercise performance based on the exercise intensity - a systematic review
Systematic review included 11 heterogeneous trials. Some high-intensity outcomes favored acute or chronic carnitine formulations, while moderate-intensity performance did not improve. Different chemical forms, doses,…
7 published studies referenced in the app, each with a plain-language summary.