Background Coenzyme Q10 (CoQ10), a vital mitochondrial antioxidant, may enhance cardiovascular recovery and delay fatigue in athletes. This double-blind, randomized, placebo-controlled trial investigated CoQ10’s effects on cardiac stress markers and exercise performance in 16 professional soccer players. Methods Participants received either CoQ10 (n = 8) or placebo (n = 8) for 30 days and completed exhaustive aerobic cycling tests pre- and post-supplementation. Blood samples were collected at six time points to analyze GDF-15, NT-proBNP, and hs-TnT levels. Results In the CoQ10 group, GDF-15 rose post-exercise (PreEx1-PostEx1: +8.84%, p = 0.003; PreEx2-PostEx2: +5.37%, p = 0.001) but declined by 24 h post-Ex1 (− 5.28%, p = 0.003) and 24 h post-Ex2 (-6.62%, p = 0.001) compared to post-Ex1 & post-Ex2, respectively. NT-proBNP increased post-Ex1 (19.66%, p = 0.001), post-Ex2 (12.09%, p = 0.001) but decreased in 24 h-Ex1 (− 20.28%, p = 0.001), 24 h-Ex2 (-20.83%, p = 0.001) compared to post-Ex1&Ex2, respectively. Following a 31.18% increase post-Ex1, a smaller 23.65% increase was observed post-Ex2 in hs-TnT levels, however, decreases of -19.57 and − 32.20% were observed 24 h- postEx1&Ex2 compared to post-Ex1&Ex2, (p = 0.001 for all). Time to fatigue (TTF) improved post-supplementation (− 0.5%, p = 0.002), whereas the placebo showed no change (− 0.08%, p = 0.793). Conclusions CoQ10 supplementation significantly reduced post-exercise cardiac stress markers (GDF-15, NT-proBNP, hs-TnT) and improved TTF in athletes. These findings suggest potential associations with reduced cardiac stress responses to exercise, but further studies are required to confirm the clinical significance and long-term effects of CoQ10 supplementation on cardiovascular health in athletes. Trial registration not applicable.
