L-Carnitine
amino acids
L-Carnitine is a naturally occurring amino acid derivative that plays a crucial role in transporting long-chain fatty acids into mitochondria for energy production. It is synthesised in the body from lysine and methionine, and is also found in animal products, making deficiency rare in those consuming adequate protein.
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Benefits
Dosage
Typical Dose
2-4 grams per day
Upper Limit
6 grams per day
Timing
With meals, or pre-workout for performance benefits
Forms & Bioavailability
L-Carnitine L-Tartrate
High absorption, rapidly absorbed, preferred for acute performance benefits
Acetyl-L-Carnitine (ALCAR)
Highly bioavailable, crosses blood-brain barrier, better for cognitive support
Propionyl-L-Carnitine
Good absorption, supports vascular function
Side Effects
Interactions
Research Summary
Research demonstrates that L-Carnitine supplementation can improve aerobic exercise performance and fat oxidation, particularly in those with low baseline levels. Studies on cognitive function, particularly with ALCAR, show promise for age-related cognitive decline and neurological health. However, evidence for fat loss is mixed and most effective when combined with exercise and caloric restriction.
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The Bottom Line on L-Carnitine
L-Carnitine is moderately researched with promising but sometimes mixed evidence.It is most commonly used for enhanced fat oxidation and energy production and improved exercise performance and endurance. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.
About Our Research
This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.
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Goal Guides for L-Carnitine
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