Alleviation of inflammation requires an optimal balance between pro and anti-inflammatory cytokines, in which IL-10 plays a critical role as a major anti-inflammatory cytokine. Studies about the ability of the active component of Spirulina platensis to promote IL-10 expression still vary. This study aims to analyze the effect of S. platensis on IL-10 mRNA expression in healthy rats of emerging adults and young adults. This study used six groups of male Wistar rats aged 12, 18, and 24 weeks treated with 200 mg/kg BW of S. platensis extract and a control group. Molecular interaction was predicted between three bioactive compounds of S. platensis (α-glucan, β-carotene, phycocyanobilin) and tacrolimus (control ligand) with IL-10 protein. The relative expression ratio of IL-10 mRNA increased in the treatment rats at 12 weeks (1.77) and 24 weeks (2.05). In rats aged 18 weeks, there was no increase in the expression ratio of IL-10 mRNA in treated rats compared to controls (0.91). Tacrolimus, the control ligand, has the best affinity as an IL-10 inhibitor (-6.68 kcal/mol), followed by β-carotene (-5.83 kcal/mol). The ethanolic extract of S. platensis can potentially increase the expression of IL-10 mRNA in the rat spleen at 12 and 24 weeks. © Published under licence by IOP Publishing Ltd.