Astaxanthin (AST), a marine xanthophyll with antioxidant, anti-inflammatory and immunomodulatory activity, is constrained by hydrophobicity, photo-oxidative instability and a vehicle- and prandial-state-dependent oral bioavailability of ≈10–50%. We critically appraise nanodelivery systems (NDSs) for AST — primarily oral liposomes, nanoemulsions, solid lipid nanoparticles, nanostructured lipid carriers, polymeric nanoparticles, Pickering emulsions and layer-by-layer microcapsules, with emerging exosome and electrospun-nanofibre platforms and selected parenteral examples — that improve solubility, gastrointestinal stability, intestinal targeting and controlled release. Where head-to-head data exist, nano-AST achieves 2- to 10-fold gains in peak plasma concentration (C max ) and area under the curve (AUC) over oil-based references. Nano-AST reshapes the gut microbiome–host metabolic axis through short-chain fatty acids, bile acids and tryptophan-derived aryl hydrocarbon receptor (AhR) ligands, attenuating inflammaging, improving glucolipid homeostasis and supporting neuroprotection. We summarize regulatory positioning, the global market and representative human studies, and identify multi-omics integration, scalable manufacture and head-to-head clinical trials as translational priorities.
Feng et al. (2026) studied this question.