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Amino Acid

L-Carnitine Fumarate

Also known as: L-carnitine, LCAF, carnitine fumarate, levocarnitine fumarate

B
Evidence

L-carnitine is a compound synthesized from amino acids that facilitates the transport of long-chain fatty acids into mitochondria for energy production. L-carnitine fumarate is a salt form that may have improved bioavailability compared to base L-carnitine.

Primary uses

  • Energy metabolism and endurance performance
  • Fatty acid oxidation support
  • Exercise recovery
  • Cardiovascular health

How it works

  • Transports long-chain fatty acids across the inner mitochondrial membrane (CPT I system) for β-oxidation
  • Enhances cellular energy production from fat metabolism
  • May improve exercise capacity and reduce fatigue

Dosage

Typical range
2,000–4,000 mg daily
Timing
Split into 2–3 doses; pre-workout timing may be beneficial for performance studies
With food
Can be taken with or without food; may improve absorption with carbohydrates and protein
Duration
Studies typically assess benefits after 2–4 weeks of consistent use; effects may increase with longer duration
Special populations
Vegetarians and vegans may benefit most as carnitine is primarily dietary in origin. Dose adjustments may be needed in renal disease; consult healthcare provider.

Forms

  • Powder· 70/100
  • Capsule· 70/100
  • Liquid· 70/100
  • Tablet· 70/100

Safety

Common side effects

  • Fishy body odor (due to TMAO production)
  • Nausea
  • Abdominal discomfort
  • Diarrhea

Contraindications

  • Seizure disorders (historical concern; current evidence is inconclusive)
  • Advanced kidney disease (risk of carnitine accumulation)
  • Hypersensitivity to carnitine or fumaric acid components

Evidence notes

L-carnitine has moderate-to-good evidence for improving endurance performance and fatty acid oxidation in trained athletes and certain clinical populations. The fumarate form offers no additional advantage over standard L-carnitine based on current evidence, but the salt may improve absorption.

Grade B: Some human trials support key claims; further confirmation needed.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.