Total and free carnitine

The role of carnitine in the body

Carnitine , an amino acid-like compound critical for energy metabolism. , comes in two forms::

• Free carnitine (L-carnitine) is a biologically active form
• Acylcarnitine (associated with fatty acids)

Main functions:

1. Transport of fatty acids to mitochondria for energy production (β-oxidation)
2. Detoxification (elimination of excess organic acids)
3. Heart and muscle support
4. Participation in spermatogenesis

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Norm of carnitine in the blood

Parameter	Reference range (µmol/L)
Total carnitine	40–60
Free carnitine	35–55
Acylcarnitine	5–15
Ratio (acyl/free)	<0.4

Note: In children, the levels are 10-20% higher.

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Carnitine deficiency

Reasons:

• Primary deficiency (genetic defects of transport)
• Secondary deficiency (strict diet, liver/kidney diseases)
• Taking valproate (an anticonvulsant drug)

Symptoms:

• Muscle weakness
• Hypoglycemia
• Cardiomyopathy
• Developmental delay in children
• Increased fatigue

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Excess Carnitine

Reasons:

• Overdose of L-Carnitine supplements
• Kidney failure
• Metabolic disorders

Symptoms:

• Nausea, diarrhea
• Fishy body odor (trimethylaminuria)
• Arrhythmias
• Muscle spasms

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What should I do if there are deviations?

If there is a shortage:

1. Urinalysis for organic acids
2. Genetic testing (for primary forms)
3. L-Carnitine supplements (50-100 mg / kg / day for children)

If there is an excess:

1. Cancellation of supplements
2. Low Carnitine diet (less red meat)
3. Hemodialysis (at critical levels)

Important:

• Vegetarians have 10-25% lower carnitine levels (normal in the absence of symptoms).
• Taking 2500-5000 mg/day supplements may cause side effects

Example of interpretation:

Note for athletes: Additional carnitine supplementation has not been shown to be effective in improving results in healthy individuals!