Bauer · Reproductive sciences (Thousand Oaks, Calif.) 2019 · pre-post interventional study · n=17

Reduction in FSH Throughout the Menstrual Cycle After Omega-3 Fatty Acid Supplementation in Young Normal Weight but not Obese Women.

Cited 10 times in the scientific literature.

Level 4 - case-series / case-control

Uncontrolled before-and-after interventional study with no parallel control group.

PubMed 30773100 · doi:10.1177/1933719119828099 · record verified 2026-08-26

What was done

Seventeen eumenorrheic women aged 24 to 41 years participated in a pre-post interventional trial. Participants collected daily morning urine for one menstrual cycle before and one cycle after taking 4 g/day of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for one month. Researchers measured urinary follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen metabolites, progesterone metabolites, plasma fatty acid profiles, and endoplasmic reticulum stress markers.

What was found

Omega-3 compliance was confirmed by a significant reduction in the plasma omega-6 to omega-3 ratio across all participants (P < .01). In normal-weight women, urinary FSH significantly decreased after supplementation during both the follicular phase (-28.4%, P = .04) and the luteal phase (-12.6%, P = .04). No significant changes in FSH occurred in obese women, and no significant changes were observed in LH or sex steroid metabolites in either group.

Why it matters

High-dose omega-3 fatty acids selectively suppress FSH secretion across the menstrual cycle in normal-weight women, pointing to a potential non-hormonal nutritional modulator for conditions involving elevated FSH or ovarian reserve issues.

Limits

The sample size was very small (n = 17) and lacked a parallel placebo control group to rule out cycle-to-cycle variation. The duration was limited to one month, and clinical reproductive outcomes (such as ovulation rates or pregnancy) were not evaluated.

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