According to the results of a recent systematic review published in Psychosomatic Medicine, acetyl-L-carnitine supplementation reduces depressive symptoms relative to placebo and is well tolerated compared with antidepressants.
In this systematic review and meta-analysis, 12 randomized controlled trials (n=791; mean age 54 years; 65% women) that evaluated the efficacy and safety of acetyl-L-carnitine compared with placebo, no intervention, or antidepressants were analyzed. Studies that evaluated acetyl-L-carnitine either alone (n=11) or in combination with antidepressants (n=1) were included.
According to pooled data from 9 randomized controlled trials, acetyl-L-carnitine reduced depressive symptoms significantly compared with placebo or no intervention (standard mean difference [SMD] -1.10; 95% CI -1.65 to -0.56; I2=86%).
Acetyl-L-carnitine had a larger effect in older participants (SMD -1.52; 95% CI -2.09 to -0.96; P <.001), whereas the effect in younger participants was not statistically significant (SMD -0.35; 95% CI -0.75 to 0.05; P =.093). Similarly, increased acetyl-L-carnitine doses were associated with increased improvements in depressive symptoms (P =.01; R2 0.54).
Compared with antidepressants, acetyl-L-carnitine had a similar effectiveness in reducing depressive symptoms according to the results of 3 randomized controlled trials (SMD 0.06; 95% CI -0.22 to 0.34; I2=31%). Acetyl-L-carnitine, however, was associated with a reduced risk for adverse events compared with antidepressants (odds ratio 0.21; 95% CI, 0.12-0.36; P <.001).
The study investigators concluded that acetyl-L-carnitine “appears to have a similar effect to some common antidepressant agents with significantly fewer side effects.” They noted that “future [randomized controlled trials] with a larger sample size and in healthy participants could be important to see if [acetyl-L-carnitine] is able to prevent depression.”
Veronese N, Stubbs B, Solmi M, Ajnakina O, Carvalho AF, Maggi S. Acetyl-l-carnitine supplementation and the treatment for depressive symptoms: A systematic review and meta-analysis [published online October 25, 2017]. Psychosom Med. doi: 10.1097/PSY.0000000000000537