Dose-Dependent Effects of Astaxanthin on Exercise-Induced Muscle Damage in Exercising Males

Astaxanthin (AX) is a potent antioxidant and an anti-inflammatory carotenoid. Research examining whether AX could counteract exercise-induced muscle damage and improve exercise capacity has reported inconsistent results. The aim of this study was to test the efficacy of high-dose versus low-dose AX supplementation for four weeks on muscle damage markers, total antioxidant status, and a subjective marker of muscle pain following exhaustive exercise. A total of 24 active males were randomly assigned to one of the three groups: an AX12 group (12 mg·day⁻¹; n = 8), an AX36 group (36 mg·day⁻¹; n = 9) or a placebo group (PLC, n = 7). After four weeks of supplementation, blood samples were collected at rest, and at 2, 24, 48, and 72 h following eccentric arm exercise performed at 85% of the predetermined one-repetition maximum to assess muscle damage markers and total antioxidant status, and muscle pain levels were evaluated using a Numerical Visual Pain Scale0–10. Creatine kinase activity was significantly lower in AX groups compared to the PLC group at 24, 48, and 72 h post-exercise (p < 0.05), with no difference between both AX groups (p > 0.05). At 24, 48, and 72 h post-exercise, lactate dehydrogenase activity in the PLC group was higher than in AX12 and AX36 groups, averaging 2.2 and 2.8 times higher, respectively; however, these differences were not statistically significant (p > 0.05). A significant time effect of the muscle pain score was noted at 2, 24, 48, and 72 h post-exercise (p < 0.001), with no significant differences among the supplementation protocols (p > 0.05). In conclusion, four-week AX supplementation at a dose of 12 or 36 mg·day⁻¹ similarly reduces plasma creatine kinase activity following exhaustive exercise, yet its impact on muscle pain and antioxidant status remains limited.