Author(s): CHAHAR, A., KUMAWAT, K.R., DHAKA, A., PAREEK, A., PUROHIT, S.G., SINGH, N., Institution: CENTRAL UNIVERSITY OF RAJASTHAN, Country: INDIA, Abstract-ID: 1825

INTRODUCTION:
Creatine and caffeine are widely utilized ergogenic aids in sports, yet their individual and combined effects on anabolic-catabolic hormonal balance remain inadequately characterized. This study examined the effects of creatine monohydrate, caffeine, and combined supplementation on testosterone, cortisol, and aerobic performance markers in combat sport athletes.
METHODS:
Thirty-six trained combat athletes (age: 22.2±1.3 years; BMI: 21.1±2.4 kg/m²) were allocated to control(n=10), creatine (n=10), caffeine (n=10), or combined creatine-caffeine (n=6) groups. Hormonal markers (testosterone and cortisol) and physiological–metabolic indicators (VO₂max, RHR, RER, and VT₂) were assessed using
Cardiopulmonary Exercise Testing (CPET) K5 COSMED, Rome, Italy. Statistical analysis: one-way ANOVA with post-hoc independent t-tests comparing each supplementation group to baseline control. Effect sizes calculated using Cohen's d. Significance set at α=0.05.
RESULTS:
Testosterone concentrations differed significantly across groups (F₃,₃₂=13.03, p<0.001). Compared to baseline control (4.92±0.94 ng/mL, n=10), all supplementation groups exhibited marked testosterone elevation: creatine 7.41±2.41 ng/mL (+50.6%, p=0.007, d=1.36); caffeine 9.65±1.94 ng/mL (+96.2%, p<0.001, d=3.11); combined 11.19±3.43 ng/mL (+127.4%, p<0.001, d=2.50). All effect sizes were large (d>0.8), with caffeine demonstrating the most robust statistical effect (d=3.11). RHR showed significant group differences (F₃,₃₂=8.51, p<0.001), with caffeine producing elevated values (85.6±11.0 bpm, +18.9% vs. baseline, p=0.007, d=1.37) while combined supplementation yielded the lowest RHR (66.5±5.5 bpm, -7.6% vs. baseline). Caffeine significantly reduced RER (1.01±0.13 vs. baseline 1.14±0.10, -11.2%, p=0.023, d=-1.11), indicating altered substrate oxidation. VO₂max (p=0.431), VT₂ (p=0.711), and cortisol (p=0.129) showed no significant differences. Testosterone/cortisol ratios were most favourable in caffeine (0.124) and combined (0.123) groups.
CONCLUSION:
Combined creatine–caffeine supplementation produced the greatest absolute increase in testosterone (+127.4%, d = 2.50), while caffeine alone showed the strongest statistical effect (d = 3.11), indicating it may be the main driver of the hormonal response. All supplementation strategies demonstrated statistically significant, large effect sizes. Notably, hormonal changes occurred independently of aerobic capacity (VO₂max unchanged, p = 0.431), suggesting separate mechanisms. These findings support creatine–caffeine co-supplementation for hormonal optimization in athletes, though long-term safety and performance effects require further study.