The growing demand for natural alternatives to synthetic compounds has propelled the large-scale production of microalgae and their bioactive constituents. Among these, phycocyanin, a prominent pigment abundant in blue-green algae, has emerged as a subject of intense research interest due to its multifaceted biological activities, which include antioxidative, anti-inflammatory, anticancer, and neuroprotective properties. Its versatility has led to widespread use across various industries, from food and cosmetics to pharmaceuticals, underscoring its economic significance. As a result, efforts have been intensified to refine production processes, enhance purity, and ensure stability to increase its market value. Furthermore, the exploration of secondary metabolites derived from microalgae production holds promise for cross-industry applications, fostering industrial symbiosis and a circular economy. This chapter aims to elucidate the antioxidant capacity of phycocyanin derived from microalgae and delve into its potential for therapeutic approaches.