Energy drinks contain caffeine, taurine, and B-vitamins, which are purported to enhance muscular performance by blunting fatigue and enhancing muscle fiber recruitment. While their effects on endurance sports are well-studied, their impact on strength, power, and endurance in resistance training remains unclear. This study investigated the effects of a commercially available energy drink (Red Bull) on resistance training performance in healthy, resistance-trained men. Forty participants (age: 23.4 ± 2.2 yr; BMI: 23 ± 1.4 kg/m2) were randomly assigned to receive either Red Bull (ED) or a placebo (PLA) three times per week for five weeks. Muscular strength (one-repetition or 1-RM bench press and hand grip strength), power (vertical jump), and endurance (bench press repetitions at 70% 1-RM) were assessed. Both groups exhibited significant improvements in bench press strength (p = 0.0001), muscular endurance (p = 0.0001), and vertical jump (ED: p = 0.0001, PLA: p = 0.002) following the intervention. However, no significant differences were observed in hand grip strength (p = 0.2) within either group. While the ED group demonstrated a significantly greater improvement in muscular endurance compared to the PLA group (p = 0.005), no significant between-group differences were found for bench press strength (p = 0.3), vertical jump performance (p = 0.3), or hand grip strength (left hand: p = 0.4, right hand: p = 0.7). In conclusion, consuming a commercially available energy drink during a five-week resistance training program did not enhance strength gains in resistance-trained men but may improve upper limb muscular endurance.