Vitamin E, specifically in the form of alpha-tocopherol (not alpha-tocopheryl hydrochloride, which is not a standard form), has been investigated for its role in reducing certain side effects of chemotherapy, particularly chemotherapy-induced peripheral neuropathy (CIPN). Several clinical studies and meta-analyses have looked at vitamin E supplementation as a neuroprotective agent during chemotherapy regimens that include agents like cisplatin, paclitaxel, or oxaliplatin, which are known to cause neuropathy in some patients.

Some randomized controlled trials have shown that vitamin E supplementation (usually at doses of 300-600 mg/day) can reduce the incidence and severity of CIPN. For example, a 2011 meta-analysis found a modest benefit of vitamin E in preventing neurotoxicity without significant adverse effects. However, other studies have failed to confirm these findings, and concerns remain regarding the potential for antioxidants like vitamin E to interfere with the therapeutic efficacy of chemotherapy. There is little evidence to support vitamin E for other chemotherapy side effects such as nausea or mucositis.

Major guidelines (such as those from the American Society of Clinical Oncology) do not recommend routine vitamin E supplementation for chemotherapy patients due to inconsistent efficacy data and unresolved safety concerns. Thus, scientific evidence exists, but it is limited and not definitive, supporting a rating of 2 on the evidence scale.