Long-Term Feeding of DL-α Lipoic Acid to Dogs Is Safe

Alpha-lipoic acid is well known as a covalently bound enzyme cofactor. In addition, lipoic acid has other cellular and molecular functions that have been explored in recent years, including its role as a powerful antioxidant. This study was designed to evaluate the safety of long-term oral exposure to DLα-lipoic acid in dogs. Thirty healthy dogs (≥ 1 year; 15 male, 15 female) were enrolled in this randomized, placebo-controlled study for 12 months. The dogs were randomly assigned to one of five treatment foods with varying target inclusion levels of lipoic acid (0, 150, 1500, 3000, and 4500 ppm). Daily food intake, weekly body weights, monthly physical examinations, and monthly hematology and serum biochemistry were monitored to ensure the safety of the treatments. Twenty-eight dogs completed the study. Food intake was highest for the food with the highest lipoic acid concentration. The average lipoic acid exposure for the different treatments groups were 0.31, 2.53, 26.3, 52.9, and 87.7 mg/kg body weight/ day. Body weights did not differ between the treatment groups over time. There were statistically significant changes in certain blood parameters over time, but none of the trends were biologically significant, and the values stayed within or very close to the normal reference range. This study shows that longterm lipoic acid intake of up to 52.9 mg/kg body/day (3000 ppm diet) does not have any negative effects on the health of adult dogs.