Which supplements are the most studied for cancer?

Some examples of well-studied herbal supplements in the context of cancer are traditional Eastern herbal medicines, garlic, caffeine, guarana, spearmint and peppermint. A decades-old body of research also points to the use of cannabis and CBD for managing symptoms of cancer treatment. Vitamins and nutrients that have been thoroughly studied include vitamin D, vitamin E, vitamin C, vitamin A and beta-carotene, selenium, zinc, and combinations of these vitamins. Supplements that may improve gut health symptoms caused by cancer treatment include glutamine, probiotics, ginger, short-chain fatty acids, proteolytic enzymes, kefir, honey, and propolis, among many others.