Introduction: Creatine is a highly researched supplement that shows highly positive potentials. There are studies that have linked the positive effects of creatine supplementation to different types of pain. The aim of this study was to determine the effects of creatine + GAA supplementation on the level of menstrual pain in the female population. Materials and methods: Statistical analysis was performed in 20 subjects (age 23.7 ± 2.8, BMI 21.5 ± 2, BW 61.8 ± 8.1). Subjects were divided into an intervention group (n = 10) and a placebo group (n = 10). The intervention group used 2.5 g creatine monohydrate + 2.5 g guanidinoacetic acid, while the placebo group used 5 g maltodextrin, a white creatine-like powder. Body composition was altered by bioelectrical impedance. Other measurements included: heart rate, blood pressure, body girth, skin folds, height and body weight. The questionnaires used for this study were in the short form of the IPAQ, the VAS pain scale ranging from 1 to 10, the compiled questionnaires for menstruation and the menstrual cycle. Results: The results showed a significant reduction in pain levels (VAS scale) between the initial measurement (6.5 ± 2.1) and the first menstrual period (4.0 ± 2.6) and the second menstrual period (4.0 ± 2.7) during supplementation although there were no statistically significant differences compared to the placebo group either for the first measurement (creatine + GAA 3.8 ± 2.4; maltodextrin 4.1 ± 2.9) or for the second measurement (creatine + GAA 4.1 ± 2.5, maltodextrin 3.9 ± 3). There were also no statistically significant differences in pain levels between first and second menstrual periods during supplementation. Conclusion: Creatine monohydrate combined with guanidinoacetic acid can potentialy reduce pain levels during menstruation.