Spirulina a multicellular, blue-green alga has drawn attention as a viable food supplement due to its suitable nutrient composition, however, there is a dearth of information regarding its safety. This study aimed to measure the heavy metal concentrations in commercially available Spirulina products and evaluate the safety using the in vivo method. A total of 54 mice were randomly divided into three groups; Group 1 (n = 18) served as a control and received a basal diet. Group 2 (n = 20) served as a test and received Spirulina powder (15%) blended with a basal diet. Group 3 (n = 16) serves as a standard and received a basal diet supplemented with nutritional supplements. The findings showed that the concentration of serum aspartate aminotransferase, alanine aminotransferase, cystatin C, and troponin I after consuming the experimental diets was not statistically different between groups (p > 0.05). The concentrations of mercury (0.000036 mg/kg), lead (0.0047 mg/kg), cadmium (0.00048 mg/kg), and arsenic (0.0046 mg/kg) was very little to cause toxic effect and the levels were below the European Communities Commission (EC) recommended maximum heavy metal levels in foodstuffs. Therefore, consumption of Spirulina at a proportion of 15% does not exert any hepatic, renal, and cardiac toxicities in the mice. However, evaluating the safety of higher doses (> 15%) is required.