trainResearchers in China performed a meta analysis of nine randomized, controlled clinical studies, looking at the possible effect L-carnitine (LC) and L-acetyl-carnitine (LAC) may have on male fertility. The study, published in the Asia Pacific Journal of Clinical Nutrition (2007; 16 Suppl: 383-90), found that supplementation with LC or LAC improved pregnancy rate, and sperm motility.

There even seems to be some evidence to support that Acetyl-L-carnitine and Propionyl-L-carnitine (PLC) may be of some benefit to men with erectile dysfunction. A placebo controlled study, published in the journal Urology (2005; 66(5): 1080-5) found that PLC and ALC improve the effects of sildenafil (erectile dysfunction drug) on patients with erectile dysfunction.