Effect of Intermittent Fasting on Reproductive Hormone Levels in Females and Males: A Review of Human Trials.
Level 5 - mechanism / opinion, no new human data
Narrative review of human trials without reported systematic methodology or meta-analysis
PubMed 35684143 · doi:10.3390/nu14112343
What was done
The authors conducted a literature review of human trials to evaluate the effects of intermittent fasting protocols on reproductive hormone levels in females and males.
What was found
The abstract reports directional outcomes without quantitative effect sizes. In premenopausal females with obesity, intermittent fasting decreased testosterone and the free androgen index while increasing sex hormone-binding globulin (SHBG), particularly when eating ended before 4 pm; estrogen, gonadotropins, and prolactin levels remained unchanged. In lean, active young men, intermittent fasting reduced testosterone levels without changing SHBG, muscle mass, or muscle strength.
Why it matters
These hormonal shifts suggest intermittent fasting may help manage hyperandrogenism in polycystic ovary syndrome, but could potentially reduce androgen levels in healthy young men.
Limits
The abstract reports no exact sample sizes, trial counts, or numerical data. The authors explicitly note that very few studies have addressed this question, making conclusions preliminary, and direct clinical outcomes (fertility, libido, metabolic endpoints) were not established.
Cited by
- contradicts Prolonged intermittent fasting, such as 16-hour fasts, in premenopausal women causes hormonal imbalances and downregulates fertility.