Astaxanthin in metabolic control: From regulatory mechanisms to therapeutic prospects

Astaxanthin, a naturally occurring exogenous antioxidant, possesses a unique molecular structure defined by conjugated double bonds and polar end groups, giving it unparalleled antioxidant capacity - exceeding β-carotene and α-tocopherol by orders of magnitude. Notably, astaxanthin surpasses traditional antioxidants not only in radical scavenging potency, but also in multiple metabolic modulating effects. Accumulating evidence confirms that dietary astaxanthin accumulates in intestinal tissues and the systemic circulation, where it orchestrates cellular signaling pathways to restore homeostasis under pathophysiological stress. Despite the well-established broad-spectrum bioactivities of astaxanthin, the multi-target regulatory mechanisms underlying its metabolic modulation remain incompletely elucidated. This review systematically unravels the structure-activity relationships that govern astaxanthin's biological potency, focusing on the mechanisms by which astaxanthin regulates oxidative stress, inflammation, autophagy, apoptosis, ferroptosis and gut microbiota-host interactions via metabolically activated molecular signaling during critical windows of health development in humans and animals. A deeper understanding of astaxanthin's mechanisms may pave the way for improved astaxanthin-based interventions in the future, ultimately advancing health management and prevention strategies. © 2025 The Author(s).