Aquatic organisms are rapidly gaining recognition as functional food components that enrich food and serve as sustainable resources. The most commonly consumed microalgae species as food are Dunaliella, Schizochytrium, Spirulina, Chlorella, and Haematococcus, all of which have been certified as "Generally Recognized as Safe" (GRAS). Research into the potential use of bioactive substances derived from microalgae as functional components has begun to create new products. The cultivation of microalgae represents a sustainable approach in many areas. Microalgae supplements are highly valuable in terms of nutrient concentration and bioavailability, particularly in omega-3 fatty acids, protein, and antioxidants. Recent research offers a broad perspective on the use of microalgae polysaccharides as prebiotics for cancer and irritable bowel syndrome prevention. While efforts continue to develop industrially significant biological products from microalgae, several successful laboratory-scale initiatives have been undertaken to increase the production of microalgae-based bioactive compounds using food and genetic engineering approaches. Consequently, microalgae are increasing their functional properties for sustainable food production and nutritional supplement innovation.