Spirulina has demonstrated anticancer properties in in vitro and animal studies, but human clinical trials are scarce.
Spirulina contains several compounds that have individually been found to have anticancer properties, and of these, phycocyanin appears to have the greatest potential. Phycocyanin extracted from spirulina has been shown in pre-clinical research to induce cell death (apoptosis) in a variety of cancer cell lines and prevent the formation of new blood vessels (angiogenesis), effectively inhibiting the proliferation of cancer cells.[1]
Additionally, some research suggests that spirulina may enhance natural killer cell activity, which could have an antitumor effect.[2][3] Several clinical trials suggest that spirulina supplementation may reverse precancerous lesions in the mouth.[4][5][6][7]