Top 20 Cancer Fighting Supplements: Evidence Based Literature Review (2026 Update)
Medically reviewed by Dr. Frank Yap, MD | Written by OneDayMD Editorial Team | Last updated October 2026 Quick Answer No single dietary supplement is established as a universal cancer treatment. Of the 17 supplements reviewed here, the deepest human evidence supports vitamin D3 (with K2 and magnesium) , polysaccharide-K (PSK) from turkey tail as an add-on to chemotherapy in Japanese trials, berberine for preventing colorectal adenoma recurrence, omega-3 fatty acids , curcumin and green tea EGCG . Even these show mixed rather than uniformly positive results. Melatonin looked promising in small trials, but the largest randomized trial found no benefit in early-stage lung cancer. A few supplements, namely high-dose beta-carotene, vitamin E and long-term high-dose B6/B12 , have been linked to higher cancer risk in specific groups. No supplement replaces conventional cancer treatment, and antioxidant pills are generally discouraged during chemo...