L-Carnitine: Overview, Uses, Side Effects, Precautions, Interactions, Dosing, and Reviews

Overview

• L-carnitine is a chemical produced in the brain, liver, and kidneys.
• Helps convert fat into energy, playing a crucial role in heart and brain function, muscle movement, and other bodily processes.
• Can be converted to other forms such as acetyl-L-carnitine and propionyl-L-carnitine.
• Used to treat L-carnitine deficiency; also used for heart and blood conditions, but lacks strong scientific evidence for these uses.

Uses & Effectiveness

Effective for:

• L-carnitine deficiency: FDA-approved for use in treating deficiency caused by genetic disorders or other conditions.

Possibly effective for:

• Chest pain (angina): Improves exercise tolerance and reduces pain when used with standard treatment.
• Heart failure: Can improve symptoms and exercise ability.
• High cholesterol or lipids: Slightly improves cholesterol and triglyceride levels.
• Kidney failure: Approved for IV use in kidney failure.
• Male infertility: Improves sperm count and movement, potentially increasing pregnancy chances.
• Myocarditis: Reduces risk in children post-diphtheria.
• Valproic acid toxicity: Prevents liver toxicity in deficiency.

Side Effects

• Oral intake: Likely safe for up to 12 months but can cause stomach upset, heartburn, diarrhea, seizures, and fishy odor in urine, breath, and sweat.
• Avoid D-carnitine and DL-carnitine: May block L-carnitine and mimic deficiency symptoms.

Special Precautions and Warnings

• Pregnancy: Safety unknown; best to avoid.
• Breast-feeding: Possibly safe in recommended amounts.
• Children: Possibly safe for short-term use up to 6 months.
• Hypothyroidism: May worsen symptoms.
• Seizures: Increases risk in those with a history of seizures.

Interactions

Moderate Interaction

• Acenocoumarol (Sintrom): L-carnitine may enhance effects, increasing bleeding risk.
• Thyroid hormone: L-carnitine may decrease effectiveness.
• Warfarin (Coumadin): May enhance effects, increasing bleeding risk.

Dosing

• Adults: Commonly used in doses of 2 grams daily by mouth.
• Children: 50-100 mg/kg daily by mouth, up to one year.
• Consult healthcare provider for specific conditions.

References

• Various studies and trials examining L-carnitine’s effects on conditions such as ADHD, diabetic foot ulcers, male infertility, Alzheimer's disease, and more.