Muscle strength and fatigue resistance increases with resistance training. Resistance training adaptations can be enhanced with single-ingredient or dual-ingredient supplementation but less is known about resistance training adaptations by multi-ingredient supplementation. We examined the effects of a commercial multi-ingredient supplement on resistance training adaptations for training-specific and non-training-specific tasks in young males. Male participants (n = 16, age 21±2 years, body mass 74.5±5.9 kg, body height 177±5 cm) had at least 1 year experience with resistance training exercises. Training (7 muscle groups, 4 sessions/week, weekly adjustments) consisted of two 6 weeks blocks with 4 weeks between blocks. During training, participants consumed placebo (i.e. maltodextrin, n = 7) or the sports nutritional supplement Cyclone (Maximuscle Ltd, UK, n = 9) (main ingredients creatine monohydrate, whey protein, glutamine and HMB) twice daily with one intake <15 min following a training session. Unpaired Student's ttest was used for placebo and Cyclone group comparison of percentage changes with p < 0.05. Effect sizes (Cohen's d) were calculated for the Cyclone group. Cyclone did not enhance maximal voluntary isometric force (MVIF) (p = 0.56), time to fatigue at 70% MVIF (p = 0.41) and peak concentric strength (60°·s-1) (p = 0.66) of m.quadriceps femoris (i.e. the non-specific training tasks). For the specific-training tasks, Cyclone did not enhance one-repetition maximum (1-RM) of lateral pull (p = 0.48) but there was a trend and large effect size for 1-RM of bench press (p = 0.07, d = 0.98) and 45° leg press (p = 0.07, d = 1.41). Cyclone resulted in an increase in number of repetitions for 80% pre-training 1-RM for lateral pull (p = 0.02, d = 1.30), bench press (p = 0.03, d = 1.20) with a trend for 45° leg press (p = 0.08, d = 0.96). Cyclone during resistance training enhanced the performance of 1-RM and number of repetitions at 80% of pretraining 1RM of some training-specific tasks, all with large effect sizes. Our observations suggest that Cyclone during resistance training substantially improves the ability to perform training-related tasks.