PURPOSE: The present study aimed to investigate the effects of 8 weeks spirulina supplementation and circuit resistance training (CRT) on asprosin, appetite, and energy balance in men with obesity and overweight. METHODS: The study comprised a single-blind randomized controlled trial. Sixty men with obesity and overweight (BMI > 25) were selected and randomly divided into four equal groups (n = 15 each) of training plus spirulina, training plus placebo, spirulina, and placebo. The participants of the training groups performed 12 movements with 40-90% maximal repetition (three sessions per week) and the supplemental groups consumed 1000 mg of spirulina per day for 8 weeks. Asprosin, appetite using visual analog scales, calorie intake, energy expenditure, and body composition were measured before and after the intervention. To analyze the data, the paired sample t-test, analysis of covariance, Bonferroni post-hoc, and Pearson correlation tests were employed using SPSS (version 20) at a significance level of p < 0.05. RESULTS: After the intervention, asprosin level (P = 0.015, P = 0.015, and P = 0.020, respectively), weight (P < 0.001, P < 0.001, and P < 0.001, respectively), calorie intake (P = 0.015, P = 0.011, and P = 0.004, respectively), and hunger (P = 0.011, P = 0.015, and P = 0.015, respectively) declined in the training plus spirulina, training plus placebo, and spirulina groups (p < 0.05). In addition, energy expenditure (P = 0.012 and P = 0.015, respectively) and fullness (P = 0.015 and P = 0.011, respectively) increased in the training plus spirulina and training plus placebo groups. The mean changes of the research indicators in the training plus spirulina group were significantly more than those of the other groups (p < 0.001). CONCLUSION: It was shown that 8 weeks of CRT and spirulina supplementation decreases the level of asprosin and improves appetite and energy balance in men with obesity and overweight.