Study Warns NAD Boosting Supplements May Make Chemotherapy Less Effective

Millions of Americans take supplements such as nicotinamide mononucleotide, nicotinamide riboside, and nicotinamide to increase energy, support healthy aging, and protect the heart and brain. Some cancer patients also use them to help manage the harsh side effects of chemotherapy. But a new study from Case Western Reserve University’s School of Medicine, published in Cancer Letters, suggests these vitamin B3 derivatives may have an unintended effect in people with active cancer by helping cancer cells survive and resist treatment.

The researchers focused on pancreatic cancer, one of the deadliest cancers, with a five-year survival rate of just 13%. Because every cell in the body needs NAD+ to function, supplementing with its precursors can flood cells with fuel. In healthy people, that may be beneficial. In cancer, however, the same fuel can be used by tumor cells to strengthen their energy systems, repair chemotherapy-related DNA damage, and avoid cell death.

In both laboratory experiments and mouse models, the supplements, especially nicotinamide mononucleotide, protected pancreatic cancer cells from three standard chemotherapy drugs: oxaliplatin, 5-flurorouacil, and gemcitabine. The study found that the supplements worked against treatment in three main ways. They boosted cancer cell energy, making tumors more resilient. They also reduced oxidative stress inside tumors, weakening one of chemotherapy’s key cancer-killing mechanisms. In addition, they suppressed DNA damage and cell death, interfering with the process chemotherapy relies on to destroy cancer cells.

Study lead Jordan Winter said the findings point to a potentially concerning role for NAD+-boosting supplements when used during active cancer treatment, especially alongside chemotherapy. He called the discovery a “call to action for the medical community.”

The study does not indicate that these supplements are dangerous for healthy people. However, for patients with active cancer, particularly those receiving chemotherapy, the researchers say the risks warrant immediate attention. Winter also noted that “natural” does not always mean safe, especially in the context of cancer treatment.

The researchers are urging routine screening of supplement use among cancer patients and more clinical research on how NAD+ supplements interact with cancer therapies. For now, they advise patients to discuss possible risks with their oncologist and medical team right away.