Time-Restricted Eating and Female Hormones: What the Evidence Actually Shows

Time-restricted eating has become one of the most popular dietary strategies for weight management, but a critical question has remained largely unanswered: what does it do to female reproductive hormones? For women managing conditions like PCOS, or those simply concerned about hormonal health, this gap in knowledge matters enormously.

This systematic review from researchers at the University of Queensland searched four major databases and identified six studies — including randomized controlled trials and non-randomized designs — that examined TRE's effects on reproductive hormones and androgen markers in adult women up to May 2024. Hormones assessed included testosterone, estrogen, progesterone, luteinizing hormone (LH), cortisol, DHEA, and sex hormone-binding globulin (SHBG).

The findings split along population lines. In women with general obesity (BMI over 30), RCTs consistently showed no significant changes in any of the measured hormones during TRE. This is largely reassuring — it suggests that adopting TRE for weight loss is unlikely to disrupt the hormonal milieu in otherwise healthy obese women. In contrast, non-randomized studies focused on women with PCOS reported meaningful improvements, including decreased testosterone and LH levels — hormonal shifts that would be clinically beneficial for this condition.

However, the PCOS findings come with an important asterisk. Because these were non-randomized studies and weight loss occurred alongside TRE, it is impossible to determine whether hormonal improvements resulted from TRE specifically or simply from the caloric deficit and accompanying weight reduction. The confounding effect of weight loss looms large.

With only six eligible studies — varying widely in design, duration, and population — the evidence base is too thin to support definitive conclusions. The authors call for longer, well-controlled RCTs specifically designed to isolate TRE's hormonal effects, particularly in women with PCOS, where the therapeutic potential appears most promising.