05 Jan 2022 --- Combining over-the-counter iron with Regular Girl, a supplement containing Taiyo’s Sunfiber prebiotic fiber, may improve iron uptake with no known side effects in female athletes, according to a US study.Regular Girl also contains Bifidobacterium lactis probiotics. Last year, Sunfiber received Informed Ingredient certification verifying that products have been regularly screened for a wide variety of substances prohibited in sports nutrition products, ensuring their protection and efficacy in athlete-specific formulations.