l carnitine role in the body L-Carnitine functions as a cofactor for long-chain fatty acids across Understanding the Benefits and Uses
Description
So as long as youre feeding your dog the correct amount of food a L-carnitine supplement could be beneficial especially in working dogs and Labradors

Endocrinology 154 , 537549 (2013)

Trends Endocrinol Metab 20(7):318324 Martnez-Iglesias O, Garca-Silva S, Regadera J et al (2009) Hypothyroidism enhances tumor invasiveness and metastasis development

PMID 16316746
