Schlie et al. 2025, Menstrual cycle phases and athletic performance — hormone-verified systematic review

A systematic review restricted to studies that verified cycle phase using 17β-estradiol, progesterone, and luteinising hormone measurement — a higher bar than most prior syntheses. Covering 19 studies and 279 participants, the review found heterogeneous and often contradictory results across performance outcomes; even with hormone-confirmed phases, there is no consensus on which phase is best for performance. The results reinforce the methodological critique of the field while demonstrating that rigorous verification alone does not resolve the inconsistency. Moderate evidence.