biotin

Doctors warn that biotin supplements may interfere with cancer care by distorting blood markers and masking cancer recurrence. Cancer patients often take biotin to restore hair lost during treatment, but there is little evidence it helps. The supplement can delay treatment decisions and do more harm than good.

Cancer cells rely on glutamine but can switch fuels using vitamin B7 (biotin), which acts as a metabolic 'license' via a key enzyme. Without biotin, cancer cells lose this metabolic flexibility and stop growing. Mutations in a cancer-linked gene amplify this vulnerability, offering a potential new therapeutic target.