L-Carnitine: what it is and what to expect

What it is

L-carnitine is a compound your body makes and also gets from meat, fish and dairy. It carries fatty acids into the mitochondria, the parts of cells that turn fat into energy. Most healthy people make enough on their own.

What research says

The NIH Office of Dietary Supplements notes that research on carnitine for exercise performance has given mixed results. Some studies report small effects on body weight when it is combined with a calorie deficit and training, but it is not a replacement for either. Set realistic expectations: diet and training do most of the work.

Forms

• L-carnitine (liquid or capsules): the most common form in sports supplements.
• L-carnitine L-tartrate: often used in exercise studies.
• Acetyl-L-carnitine: usually marketed for focus rather than training.

How people use it

Follow the serving on the label. Many people take it before training or with a meal. Liquid forms are convenient but check the sugar and calories per serving.

Who should be careful

Speak to a doctor first if you take thyroid medication or blood thinners, or have kidney disease or a seizure disorder. Large amounts can cause stomach upset and a fishy body odour.

Getting the basics right

For cutting, start with a calorie target and enough protein. Our calculator gives you both.