HormeL-carnitine
It is not a reliable fat burner for healthy athletes. Modest weight-loss signals exist in other populations, which do not justify routine recommendations.
What it is for
Marketed as a 'fat burner' and fatty acid transporter.
How it works
It transports fatty acids into the mitochondria, but supplementing does not reliably increase fat oxidation.
Dosing
— (no consistent ergogenic effect).
When to take it
—
Safety
Safe; at high doses it may raise TMAO (cardiovascular relevance under study).
Side effects
Digestive discomfort, body odor at high doses.
Interactions
None relevant at normal doses.
Contraindications
Check with your doctor if you have cardiovascular disease.
Who it has been studied in
Treatment for deficiency is a clinical indication. A 2025 review found modest weight reductions in varied populations, with high heterogeneity; it does not establish routine usefulness in healthy athletes.
Frequently asked
Does it burn fat?
Not reliably in healthy people. A calorie deficit is what burns fat.
- Evidence tier
- D
- Quality
- Adequate
- Studies
- Mostly negative RCTs
- Consensus
- Consensus on its lack of ergogenic effect
- Controversy
- The TMAO/cardiovascular risk signal is under debate
- Reviewed
- 2026
Strength of evidence out of 5.