Objectives: Carnitine deficiency impairs fatty acid β-oxidation and may partly explain weight gain in valproate-treated patients. The aim of this study was to determine whether l-carnitine supplementation improves weight loss outcomes in bipolar patients taking sodium valproate.
Methods: Sixty bipolar patients with clinically significant weight gain thought to be related to sodium valproate, who had been taking sodium valproate for ≥6 months, were randomized to l-carnitine (15 mg/kg/day) or placebo for 26 weeks, in conjunction with a moderately energy-restricted, low-fat diet. The primary outcome measure was weight change.
Results: l-carnitine had no effect on mean weight loss compared with placebo (−1.9 kg versus − 0.9 kg) (F = 0.778, df = 1,58, p = 0.381). The number of people in each group able to lose any weight was identical ( = 0, p = 1.0); more patients in the carnitine group (nine versus five) achieved a clinically significant weight loss (≥5%) but this was not statistically significant (p = 1.0, Fisher's exact test).
Conclusions: At the dose prescribed in this study carnitine supplementation did not improve weight loss outcomes in valproate-treated bipolar patients consuming an energy-restricted, low-fat diet.