Abstract-based review · 2012
L-carnitine, metabolism and weight loss in overweight cats
Fat oxidation increased more at higher supplementation. Overall weight loss did not differ significantly between groups.
Review scope
Abstract-based review. Full methods, complete statistical results and product equivalence have not been appraised. This is research context, not an individual feeding or treatment recommendation.
Study question and design
32 neutered adult colony cats made overweight before the experiment. Four diets with 0, 50, 100 or 150 micrograms L-carnitine per gram food; unrestricted feeding followed by energy restriction.
Main findings
Fat oxidation increased more at higher supplementation. Overall weight loss did not differ significantly between groups.
Limitations and applicability
Colony conditions and controlled restriction limit application to household cats. Metabolic changes do not establish greater weight-loss effectiveness.
Ingredients investigated
Direct ingredient investigations
L-carnitine
Direct · cat. 32 neutered adult colony cats made overweight during six months of feeding before the experiment.
Tested form: L-carnitine added to cat food. Dose: 100 micrograms/g food (Micrograms of L-carnitine per gram of food; oral feeding. Dry-matter basis not established in the reviewed abstract). Duration: One month of unrestricted feeding, followed by restricted feeding; restricted-period duration not reported in reviewed abstract. Comparator: Food containing no added L-carnitine.
Measured finding: Overall or cumulative weight loss did not differ between groups. On day 42, the 150 micrograms/g diet group had greater palmitate flux and estimated fat oxidation exceeding 62%, versus 14% in controls. This high-dose result is not an independent estimate for the 50 or 100 micrograms/g arms.
Limitations: Colony cats and controlled feeding restriction. Group weight-loss differences were not demonstrated; commercial-food dose and full-diet equivalence require verification.
L-carnitine
Direct · cat. 32 neutered adult colony cats made overweight during six months of feeding before the experiment.
Tested form: L-carnitine added to cat food. Dose: 150 micrograms/g food (Micrograms of L-carnitine per gram of food; oral feeding. Dry-matter basis not established in the reviewed abstract). Duration: One month of unrestricted feeding, followed by restricted feeding; restricted-period duration not reported in reviewed abstract. Comparator: Food containing no added L-carnitine.
Measured finding: Overall or cumulative weight loss did not differ between groups. On day 42, the 150 micrograms/g diet group had greater palmitate flux and estimated fat oxidation exceeding 62%, versus 14% in controls. This high-dose result is not an independent estimate for the 50 or 100 micrograms/g arms.
Limitations: Colony cats and controlled feeding restriction. Group weight-loss differences were not demonstrated; commercial-food dose and full-diet equivalence require verification.
L-carnitine
Direct · cat. 32 neutered adult colony cats made overweight during six months of feeding before the experiment.
Tested form: L-carnitine added to cat food. Dose: 50 micrograms/g food (Micrograms of L-carnitine per gram of food; oral feeding. Dry-matter basis not established in the reviewed abstract). Duration: One month of unrestricted feeding, followed by restricted feeding; restricted-period duration not reported in reviewed abstract. Comparator: Food containing no added L-carnitine.
Measured finding: Overall or cumulative weight loss did not differ between groups. On day 42, the 150 micrograms/g diet group had greater palmitate flux and estimated fat oxidation exceeding 62%, versus 14% in controls. This high-dose result is not an independent estimate for the 50 or 100 micrograms/g arms.
Limitations: Colony cats and controlled feeding restriction. Group weight-loss differences were not demonstrated; commercial-food dose and full-diet equivalence require verification.
Evidence.pet interpretation
Apply this result only within its species, preparation and study conditions. An ingredient listing alone does not establish that a commercial product reproduces the tested intervention.
Funding and conflicts
Not established from the reviewed abstract.
Ingredient references
These are research references. The tested form, dose and formulation must be matched before using a result to support a product claim.
Source
Center SA; Warner KL; Randolph JF; Sunvold GD; Vickers JR. Influence of dietary supplementation with (L)-carnitine on metabolic rate, fatty acid oxidation, body condition, and weight loss in overweight cats. American Journal of Veterinary Research. 2012. DOI: 10.2460/ajvr.73.7.1002.
Primary source record (PMID 22738052) · Publisher DOI
Reviewed 2 October 2026 · Next review 2 January 2027.