This study evaluated whether a dietary supplement called acetyl-l-carnitine (ALC) improves chemotherapy-induced peripheral neuropathy or CIPN (nerve damage caused by chemotherapy drugs) in breast cancer patients.

Many chemotherapy agents have undesirable side effects. Taxane (such as paclitaxel or docetaxel) chemotherapy, commonly used to treat patients with breast cancer, is often associated with CIPN. Because CIPN is both unpleasant for patients and can lead to discontinuation (stopping) of chemotherapy, it is important to find ways to minimize this side effect. Animal studies and small clinical trials suggested that ALC, a protein compound that naturally occurs in the body, could reduce CIPN because of its nerve-protecting effects. This clinical aimed to assess whether ALC can in fact reduce or prevent CIPN in breast cancer patients.

This study included 409 breast cancer patients who were treated with taxane chemotherapy (paclitaxel or docetaxel). 208 patients also received ALC and 201 received a placebo (a substance with no medical effect used as a control when testing new drugs). After 12 weeks, ALC and placebo patients did not have different levels of CIPN. However, after 24 weeks, ALC patients had significantly worse CIPN than placebo patients. Furthermore, ALC patients reported worse functional status, or ability to perform everyday tasks, after 24 weeks compared to patients receiving placebo. These results are opposite to earlier research on ALC and CIPN.

In summary, ALC worsened, rather than improved, CIPN symptoms in breast cancer patients treated with taxane-based chemotherapy.

Talk to your doctor before taking any supplements, such as ALC.