Spirulina as a sustainable functional ingredient: nutrient density, bioactives, and food applications

), with its high protein content and rich micronutrient profile, has emerged as a promising candidate for this purpose. This review systematically evaluates the chemical composition, bioactive components, and potential health benefits relevant to food applications, drawing on peer-reviewed studies from 2015-2025. Spirulina biomass is characterized by a rich content of protein, complex carbohydrates, polyunsaturated fatty acids, vitamins, and minerals, while compounds such as C-phycocyanin, chlorophyll, β-carotene, and phenolics contribute significantly to antioxidant activity. Preclinical and limited clinical evidence indicate benefits, including reductions in oxidative stress and inflammation, improved glycemic control, improved lipid profile, and modulation of immune responses. Despite variations due to production conditions and potential contamination with heavy metals, Spirulina's low land and water requirements, along with high biomass yield, make it a sustainable protein source. Its incorporation into foods such as bakery and dairy products demonstrates potential for functional food development. Future research should concentrate on standardizing processing and encapsulation approaches to enhance sensory acceptance, and strategies such as taste masking, fermentation, and optimized product design will be key to achieving consumer-friendly, bioactive-rich products. This study emphasizes Spirulina's promise as a sustainable, functional food ingredient, and provides guidance for scalable application in the food industry.