Vitamins and Supplements — During Chemotherapy

A standard multivitamin at normal levels is unlikely to cause a significant interaction, but this depends on what is in it and what chemotherapy you are receiving. Products such as Supradyn, Becosules, and Revital all have different compositions. Bring the packet to your next appointment and let your team confirm whether to continue, hold, or switch.

Several chemotherapy drugs work by generating oxidative damage inside cancer cells. High-dose antioxidants are designed to neutralise exactly that kind of damage — the concern is that, at megadose levels, they may reduce the treatment's effect at the same time. The degree of risk varies by drug and dose. ASCO and ESMO both advise against high-dose antioxidant supplements during active treatment until your oncologist has been consulted.

Cooking with turmeric is not the concern — high-dose curcumin capsules are, because they affect how the liver processes certain drugs. Ashwagandha has effects on drug metabolism and on certain hormone-sensitive pathways. Both are worth discussing with your oncologist before continuing, particularly if you have recently increased the dose or started them during your current treatment.

Your oncologist prescribed it at a level matched to your blood test result. Prescription forms such as Calcirol sachets or Uprise-D capsules deliver a defined amount. Over-the-counter products vary in strength. Do not switch brands or adjust what you are taking without checking first. If you have been buying a different form alongside the prescription, bring both to your next appointment.

Iron supplementation during chemotherapy is decided based on blood tests, not on how tired you feel. The right approach depends on the cause of any anaemia, which your team can determine from results. If your team has prescribed iron — brands such as Feronia, Dexorange, or Livogen — continue as instructed. If you have bought iron tablets yourself, tell your team before your next cycle.

Do not stop or start anything on your own before chemotherapy begins. Bring everything you are currently taking to your first or next appointment — supplements, vitamins, herbal products, and anything from an ayurvedic practitioner or health store. Your oncologist will tell you what to continue, hold, or stop. The answer is specific to your regimen, not a blanket rule.

Tell your team at your next appointment, or call today if that is more than a week away. This is common and your team will not judge you. Bring the actual packets so they can see exactly what each one contains. If you are worried about a specific supplement you have taken throughout your treatment, that is a reason to call sooner rather than later.

Food and a standard multivitamin are not the concern. High-dose Vitamin C tablets or effervescent sachets taken specifically for immune boosting are what ASCO and ESMO flag during active chemotherapy. The evidence does not support them for strengthening immunity during treatment, and the concern about interfering with chemotherapy's mechanism is enough for most oncologists to recommend holding them until treatment is complete. Tell your team what you have been taking.