Nanoparticle formulation is very important for broadening the bioavailability of astaxanthin (AXT) in biomedical fields. In this study, glycol chitosan (GC)-decorated AXT nanoparticles (GC-AXT nanoparticles) self-organized in aqueous environment by ionic interaction between GC and AXT exhibited good long-term colloidal stability in distilled water at 25 °C for 28 days. After treatment with GC-AXT nanoparticles, the viability of L929 fibroblast cells did not show a significant change compared to that of normal cells. In lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, GC-AXT nanoparticles showed higher inhibition effects on nitric oxide (NO) production and prostaglandin E2 (PGE2) secretion than AXT. Furthermore, GC-AXT nanoparticles improved cell migration and proliferation of L292 cells in scratched cell studies. Therefore, bioavailability of AXT could be broadened by preparing AXT nanoparticles self-organized with GC. Considering these characteristics, GC-AXT nanoparticles can be potentially used for cell and tissue regeneration.