Spirulina is a microscopic blue-green algae (cyanobacteria), has gained global recognition as a potent dietary supplement owing to its exceptional nutritional profile. Rich in high-quality protein, essential amino acids, vitamins (especially B-complex and vitamin A), minerals (such as iron, calcium and magnesium), essential fatty acids and powerful antioxidants like phycocyanin, spirulina is increasingly used in both preventive health and complementary medicine. This thematic review synthesizes findings from multiple peer-reviewed studies to present a comprehensive overview of spirulina’s health benefits and physiological effects. Specifically, it examines spirulina's role in enhancing immune function, reducing oxidative stress and inflammation, supporting cardiovascular health through lipid profile modulation and improving glycemic control in individuals with metabolic disorders. The review also explores its potential in alleviating allergy symptoms, enhancing physical performance and contributing to malnutrition recovery programs. In addition, the paper discusses recommended dosage ranges for general wellness and therapeutic use, identifies groups who should exercise caution, and highlights the importance of product quality and safety testing. While current research underscores spirulina’s potential as a valuable functional food, evidence suggests that its benefits are most effective when consumed in appropriate doses and sourced from reputable suppliers. By consolidating available scientific knowledge, this paper aims to guide healthcare professionals, nutritionists and health-conscious individuals toward the informed and safe use of spirulina supplementation in various contexts.