Weight loss & metabolic health
L-Carnitine
An amino-acid derivative that carries fatty acids into the mitochondria to be burned. The injectable form is approved for carnitine deficiency.
Not a peptide. The approved medicine is used for carnitine deficiency, at 10–20 mg/kg after each dialysis session, given by a clinician. The protocol shown is the most common clinic regimen for fat loss. Evidence for fat loss is weak.
How it works
It carries long-chain fatty acids into the mitochondria, where they are burned for energy. The body makes it, and it also comes from meat.
What it is used for
Approved for carnitine deficiency, including in people on dialysis. Also used for fat loss and exercise performance.
What the evidence says
It works well for real deficiency. In healthy people, the effects on fat loss and performance are small and inconsistent.
Side effects and cautions
Nausea, stomach upset and a fishy body odor. It raises TMAO, a compound linked to heart risk in some studies. Use caution with a history of seizures.
Half-life
About 17 hours (label)
Makes sense for
- People with a diagnosed carnitine deficiency
- Active adults supporting fat metabolism
Does not make sense for
- People with a seizure disorder
- Anyone expecting large fat loss
Boost the effect
- Carbohydrates with the injection (about 80 g): insulin increases how much carnitine the muscles take up
- Aerobic exercise: gives the muscles fat to burn