Fish oil barely touches testosterone in women with PCOS

Polycystic ovary syndrome is one of the most common hormonal conditions in women, and elevated androgens, the family of hormones that includes testosterone, drive many of its most troublesome features. Omega-3 polyunsaturated fatty acids had recently been proposed as having an anti-androgenic effect in this group, which would make fish oil an appealingly simple intervention. This review set out to test whether the clinical trial evidence actually supports that proposal by pooling every eligible study of omega-3 supplementation and androgen status in adult women with PCOS.

The authors searched PubMed, ISI Web of Science, Google Scholar and Scopus up to December 2015 for clinical investigations of omega-3 supplementation in adult women with PCOS. From each study they extracted the change in three markers of androgen status: serum total testosterone, sex hormone binding globulin, known as SHBG, and dehydroepiandrosterone sulfate, known as DHEAS. Eight clinical trials involving 298 participants were eligible, and compatible results were pooled in a meta-analysis with subgroup analyses by study design and intervention length.

Omega-3 supplementation produced only a marginal reduction in total testosterone, a mean difference of -0.19 nmol/l that just missed statistical significance at p=0.054. There was no significant change in SHBG or in serum DHEAS across the pooled trials. Subgroup analyses found reduced DHEAS only in before-and-after studies, which lack a comparison group, and in interventions lasting longer than six weeks. Tellingly, the majority of those longer trials used a single-group design with no controls, which weakens even those positive signals.

The result dampens the anti-androgen hypothesis for omega-3 in PCOS: the headline markers did not move convincingly, and the encouraging subgroup findings came from the weakest study designs. The authors themselves conclude that omega-3 supplementation does not appear to significantly affect the androgenic profile in this group, and they call for properly blinded, placebo-controlled trials with long follow-up to settle the question. Until those exist, the hormonal case for fish oil in PCOS rests on thin ground.

Fish oil is widely taken for reasons that have nothing to do with hormones, and nothing here speaks against those uses. But for women with PCOS specifically hoping omega-3 will lower androgens, this pooled evidence suggests the effect, if it exists at all, is marginal. It is a useful corrective to supplement marketing that leans on the anti-androgen idea, and a reminder that borderline results from uncontrolled studies are not the same as a demonstrated benefit.