Astaxanthin supplementation and cardiometabolic risk factors in overweight and obese adults: a GRADE-assessed systematic review and meta-analysis

Astaxanthin, a marine-derived carotenoid, has shown antioxidant and anti-inflammatory properties in studies. However, its effects on cardiometabolic risk factors in overweight and obese populations remain inconclusive. Therefore, this systematic review and meta-analysis aimed to evaluate the efficacy of astaxanthin on cardiometabolic risk factors in overweight and obese adults. A comprehensive literature search was conducted to identify relevant studies published up to May 2026, using databases including PubMed, Scopus, Embase, Cochrane, and Web of Science. Standard mean differences (SMDs) or weighted mean differences (WMDs) were analyzed using a random-effects model. Risk of bias was assessed using RoB 2.0, and the certainty of evidence was rated using the GRADE approach. A total of 16 trials comprising 694 participants (346 in the intervention group and 348 in the control group) were included in this meta-analysis. Astaxanthin supplementation was associated with a significant reduction in MDA (SMD: -1.75), CRP (SMD: -0.35), IL-6 (SMD: -0.69), TG (WMD: -2.90 mg/dL), TC (WMD: -2.73 mg/dL), and LDL-C (WMD: -1.09 mg/dL), while increasing SOD (SMD: 1.37) TAC (SMD: 2.31), and HDL-C (1.04 mg/dL). No significant changes were observed in weight, BMI, TNF-α or blood pressure. Subgroup analyses revealed that longer intervention durations (≥ 12 weeks) and higher dosages (≥ 12 mg/day) yielded more pronounced lipid improvements. Astaxanthin supplementation improves oxidative stress, inflammation, and lipid profile in overweight and obese adults, supporting its potential as an adjunctive nutritional strategy for managing cardiometabolic risk factors. However, the low to very low certainty of evidence for several outcomes underscores the need for larger, well-designed trials with standardized formulations.