**Abstract**

In order to meet the ever-growing global demands for food, healthcare, and energy, among other sources, the twenty-first century has seen a significant surge in the use of microalgae. They have seen applications in varied industries ranging from pharmaceuticals to energy to even the food industry, where its role as a source of proteins shines the most among other bioactive compounds. The microalgal biomass has the innate ability to grow in varied ecological conditions and has diverse compositions. While not economically competitive with fossil fuels or other renewable energy sources such as solar and wind, microalgal sources are technically viable, and a multitude of resources and time have been poured into the research of microalgal renewable fuels (biodiesel, ethanol, hydrogen, etc.). The rich diversity of microalgae, which is still underutilized, provides a variety of physiologically active metabolites of economic importance. These bioactive metabolites have antioxidant, antibacterial, antifungal, antiviral, anti-inflammatory, and anticancer properties. The microalgal biomass is a rich source of various compounds such as fatty acids, carotenoids, polysterols, and phenolics that can be utilized to synthesize pharmaceutical compounds and other nutraceuticals. Considering microalgae as a superfood, space food, functional food, strong agent for detoxification with high content of micro and macronutrients has found potential application in occupational, systematic, and life style disorders subsequently enhancing immunity. The path from algal research to the launching of new food products or dietary supplements is strongly affected by industrial, regulatory, and nutritional considerations. Our purpose is to review and assess what is known about different food components (i.e., proteins, polysaccharides, lipids, vitamins, minerals, and antioxidants, potential toxicants) in the context of improving knowledge about the efficacy of algal foods as nutraceuticals. This review will add be an asset for food, pharma, nutra, and cosmetic sector.

**Keywords:** microalgae, nutraceutical, bioactive, food, immunity
