Effects of 4-Week Tangeretin Supplementation on Cortisol Stress Response Induced by High-Intensity Resistance Exercise: A Randomized Controlled Trial

Randomized controlled trial in professional soccer players from Chongqing Li-Fan professional football club during the winter training season. The Tangeretin arm included 12 participants (7 men, 5 women).

Participants in the active arm consumed an oral beverage containing 200 mg/day Tangeretin (Qingguoren tangeretin supplement) with 19.8 g whey protein isolate powder daily for 4 weeks. The comparator beverage contained 20 g whey protein isolate powder without Tangeretin.

Four weeks of Tangeretin supplementation attenuated the cortisol stress response to high-intensity resistance exercise and improved antioxidant status. Serum cortisol was lower in the Tangeretin group after intervention at PRE, P10, P20, and P30, with between-group differences at PRE (p = 0.036) and P30 (p = 0.031). ACTH was lower at P10 and P30, including a P30 between-group difference (p = 0.044), and SOD was higher at all time points. WBC was lower in the Tangeretin group at P20 and P30 versus placebo (p = 0.01 and p = 0.003). No adverse events were observed.

The active arm was small (n = 12), the intervention lasted only 4 weeks, and the findings come from a single professional soccer club, which limits generalizability. Outcome reporting was focused on selected biomarkers, and longer-term performance or clinical recovery effects were not established.