Effects of resistance training combined with creatine hydrochloride or creatine monohydrate supplementation on oxidative stress-antioxidant markers in trained women: a double-blind randomized placebo-controlled trial

Abstract This study evaluated the effects of resistance training (RT) combined with creatine hydrochloride (CrHCL) and creatine monohydrate (CrM) supplementation on oxidative stress-antioxidant markers in trained women. In this study, 48 young trained women were selected and randomly assigned to four groups via a double-blind method: Group 1: RT + Creatine hydrochloride (Cr-HCL) supplementation (n = 12), Group 2: RT + Creatine monohydrate-loading phase (CrM-LP) supplementation (n = 12), Group 3: RT + CrM-without loading phase (CrM-WLP) supplementation (n = 12), and Group 4: RT + Placebo (PL) supplementation (n = 12). The RT program was performed for eight weeks with three sessions per week. Blood samples were obtained before and after training to evaluate serum levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) activity. Statistical analyses were performed using the Mixed ANOVA and Bonferroni post-hoc tests at a significance level of 0.05. Following the intervention, the RT + Cr-HCL, RT + CrM-LP, and RT + CrM-WLP supplementation groups indicated significant decreases and increases in the blood levels of MDA and SOD, respectively, compared to the RT + PL supplementation group ( ). Likewise, compared with the RT + PL supplementation group, the RT + Cr-HCL, RT + CrM-LP, and RT + CrM-WLP supplementation groups showed a greater decrease and increase in the levels of serum 8-OHdG (effect size [ES] = 1.11, 0.75, 0.66 vs 0.40) and serum GPX (ES = 0.46, 0.71, 0.56 vs 0.08), respectively ( ). However, CAT did not change significantly after eight weeks of training in any group. In general, the results showed that Cr-HCl and CrM, along with RT can positively affect oxidative stress-antioxidant indices in trained women. According to the results, Cr-HCl does not cause more effects than CrM. The study was conducted based on the Declaration of Helsinki and was approved by the ethics committee of the Sport Sciences Research Institute (IR.SSRC.REC.1399.138).