L-Carnitine

Its effect against fatty liver is being studied, but the results are not yet consistent.

L-carnitine is a compound the body makes from the amino acids lysine and methionine, and meat is a natural source. It is added to many weight control cat foods. A study in overweight cats examined its effects on fat burning and weight loss. If your cat has liver or kidney disease or is on a weight loss plan, its veterinarian should set the diet.

Source: pubmed.ncbi.nlm.nih.gov

L-carnitine helps cells move fat into the mitochondria, where it is burned for energy. Makers add it to weight control and indoor cat foods on the idea that it helps a cat use fat rather than store it. It appears mostly in recipes for overweight or neutered cats.

A study in overweight cats on a weight reduction diet found that cats given L-carnitine burned more fat for energy than cats on the control diet, but overall weight loss did not differ between the groups. Weight loss itself depends on eating fewer calories than the cat burns, and L-carnitine does not replace that. Your veterinarian can set a target weight and pace.

Source: pubmed.ncbi.nlm.nih.gov

Not exactly. L-carnitine is made in the body from two amino acids, lysine and methionine, and it is often grouped with amino acids on labels and in supplements. It is not used to build proteins. Its job is moving fatty acids into cells' energy factories, the mitochondria.

Pettings gives L-carnitine 4 out of 5 and lists it as an amino acid. It appears on 31 of the 149 dry cat foods we list. The score is for the ingredient and says nothing about a food's calorie content. Each food's page shows how it scores overall.