Carnitine

Studies in people

• Open question

  Exercise performance³

  Studies of carnitine do not generally support taking it to boost physical performance, and the science is contradictory.

• Open question

  Heart health⁴

  L-carnitine may help the heart, but scientists still disagree about how well it works and how safe it is.

Study type not stated

• Concern

  Heart health and gut bacteria⁶

  Carnitine in food feeds gut bacteria that make a compound linked to heart risks.

Single cases of misuse or overdose

One person or one incident, such as an accidental overdose or a mistake in a kitchen or factory. They are real, but a single case does not show what happens at normal amounts, so the signal does not count them.

• Mood episodes in bipolar disorder⁵

  A person with bipolar disorder had a manic relapse while taking acetyl-l-carnitine for weight loss, which eased after stopping it.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.