Intermittent fasting disrupts the menstrual cycle and hormonal health in women

This study found that time-restricted eating (limiting eating to a 4–6 hour window each day) did not meaningfully disrupt most sex hormones over 8 weeks in women with obesity. One hormone, DHEA, did decrease slightly in both pre- and postmenopausal women, but stayed within normal ranges.

• The study never measured menstrual cycle regularity, which is the core of the claim — it only measured blood hormone levels
• Only 23 women participated — too few to draw firm conclusions
• The single significant finding (DHEA decrease) does not hold up when corrected for the number of hormones tested simultaneously
• The 8-week duration and only 3–4% weight loss may be too mild to show effects that longer or more intensive fasting might produce