Astragalus membranaceus Modulates Inflammatory Markers Without Enhancing Muscle Function Following Intensified Resistance Training

Background: Astragali radix is a traditional herb known for its antioxidant, anti-inflammatory, and immunomodulatory properties and has gained attention for its potential to support post-exercise recovery. However, the effects of long-term supplementation coupled with resistance training are not well understood. Methods: Twenty-four moderately active participants were recruited and randomly assigned to the Astragali radix supplementation (ASTRA, n = 13) or placebo (PLA, n = 11) group. All participants underwent 8 weeks of regular resistance training (3 sessions/week) and 2 weeks of intensified training (6 sessions/week). Results: Before (BAS), after 8 weeks of resistance training (RT), and at the end of the intensified training (IT), knee extensors’ maximal voluntary isometric contraction torque (MVIT), and leg press and leg extension one repetition max (1RM) were measured. Blood samples were collected to analyze inflammatory markers and testosterone. From BAS to after RT, MVIT, 1RM leg press, and 1RM leg extension increased in both ASTRA and PLA, with no differences between groups. After IT, MVIT, 1RM leg press and 1RM leg extension decreased in both ASTRA and PLA. CPK levels and myoglobin concentration increased while cortisol decreased significantly from BAS to IT, but no group differences were detected. TNF-α and IL-6 showed significant time × supplementation interactions, with lower values after IT in ASTRA compared to PLA. Conclusions: Astragali radix supplementation did not lead to additional benefits in muscle during the period of resistance training, nor did it prevent the decline in force following the intensified training period. However, Astragali radix supplementation prevented the increase in some inflammatory biomarkers, specifically TNF-α and IL-6, during the intensified period of training.