L-Carnitine Dosage Calculator
The mitochondrial fatty acid transporter. L-carnitine facilitates fat oxidation, reduces exercise-induced muscle damage, and accelerates post-exercise recovery — with distinct effects depending on the form used.
What is L-Carnitine?
L-carnitine (β-hydroxy-γ-trimethylammonium butyrate) is a quaternary ammonium compound synthesised from lysine and methionine in the liver and kidneys. Its primary role is transporting long-chain fatty acids across the inner mitochondrial membrane for beta-oxidation, making it the rate-limiting step in lipid energy metabolism during prolonged exercise. Beyond fat transport, carnitine also removes toxic acyl groups from mitochondria (as acylcarnitines), preventing CoA sequestration and maintaining metabolic flexibility. Three forms dominate clinical research: L-carnitine tartrate (LCT) for muscle recovery; ALCAR (acetyl-L-carnitine) for cognitive and neuroprotective effects; and GPLC (glycine propionyl-L-carnitine) for nitric oxide and blood flow. A 2011 meta-analysis (Orer & Guzel) confirmed that carnitine supplementation significantly reduces muscle soreness markers (CK, LDH) and accelerates recovery from eccentric damage, particularly relevant for high-volume training blocks.
How to Take L-Carnitine
**Muscle recovery (L-carnitine tartrate):** 0.03–0.05 g/kg body weight (2–4 g for most adults), taken immediately post-workout with carbohydrate (insulin spike enhances muscle carnitine uptake — a critical co-factor often overlooked). **Fat oxidation / endurance:** 1.5–2 g/day with a carbohydrate-containing meal. **Cognitive / neuroprotective (ALCAR):** 500–1,500 mg/day in 1–2 doses, which can be taken without food. Daily carnitine supplementation requires 12–24 weeks to fully elevate muscle carnitine stores — acute performance benefits are modest; long-term tissue saturation is the goal.
Timing Recommendations
**Post-workout is optimal for muscle recovery** — carnitine uptake into skeletal muscle is insulin-dependent, so consuming with 30–50 g of carbohydrates (and ideally 20–40 g protein) immediately after training maximises muscle uptake. For fat oxidation goals, take 30–60 minutes before fasted morning cardio. ALCAR for cognitive effects can be taken in the morning without food for maximum CNS availability.
Potential Side Effects & Safety
GI discomfort (nausea, cramps, fishy body odour from TMAO conversion) at doses > 3 g/day in sensitive individuals. A 2013 observational study (Koeth et al., Nature Medicine) raised concern about TMAO (trimethylamine N-oxide) production from carnitine gut bacteria fermentation being atherogenic — this remains debated. At standard supplemental doses (1–3 g/day), clinical evidence of cardiovascular harm is absent and the benefit-risk ratio appears favourable in athletes. Hypothyroidism reduces carnitine uptake into tissue — thyroid function should be optimised for maximal carnitine efficacy.
Who should avoid L-Carnitine?
Individuals with trimethylaminuria (fish odour syndrome) — carnitine is converted to TMA, worsening symptoms. Seizure disorders: ALCAR (acetyl-L-carnitine) may lower seizure threshold at high doses. Hypothyroidism: severely impairs carnitine tissue uptake. Peripheral vascular disease patients on anticoagulants should monitor carefully as carnitine may modestly enhance anticoagulant effects.
Best Stacks with L-Carnitine
L-carnitine tartrate + whey protein + fast carbohydrate (banana, white rice) as an immediate post-workout recovery meal maximises insulin-mediated muscle carnitine uptake. ALCAR + alpha-GPC + lion's mane for a cognitive-longevity stack. L-carnitine + CoQ10 for mitochondrial function optimisation in endurance athletes.
Scientific References
All dosage recommendations are grounded in peer-reviewed research.
- 1L-carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women
International Journal of Sport Nutrition and Exercise Metabolism · 2011
- 2Carnitine supplementation and exercise performance: an updated meta-analysis
European Journal of Sport Science · 2020
L-Carnitine Dosage Calculator
Personalized to your body weight
Enter your weight above to see your personalized dosage
Safety notes
- Take post-workout with 30–50 g carbohydrates — insulin is required for muscle carnitine uptake.
- Fishy body odour at doses > 3 g/day — reduce dose or switch to ALCAR form.
- Muscle carnitine saturation takes 12–24 weeks of daily supplementation.
- Hypothyroidism severely reduces carnitine tissue uptake — optimise thyroid function first.
This calculator provides general guidance only. Always consult a qualified healthcare professional before starting any supplement.