A New Study Finds that Ginkgo May Impair Reproductive Function

Reproduction is a complicated process controlled by extra- and intracellular regulators of brain chemistry and gonadotropins. And plant molecules can affect these processes at every level. A recent study examined the effects of ginkgo (Ginkgo biloba) on female reproductive processes.

Why is gingko still so popular?

Many internet ads claim that extracts of the gingko plant can improve blood circulation, reduce the symptoms of old age and improve memory. At least 35 unique human interventional studies have evaluated these three claimed health effects for G. biloba during the past decade. Without exception, none of these health claims are supported by the available evidence.

In general, ginkgo is well tolerated, although many users report gastrointestinal disturbances, headaches, dizziness, tinnitus, peripheral visual shimmering, allergic and hypersensitivity reactions, such as skin rash, increased bleeding after surgery, and lowered seizure threshold. Raw ginkgo seeds contain highly toxic cyanide-containing molecules. Some ginkgo extracts are carcinogenic.

Effects on female reproductive processes

A recent report documented the reproductive toxicity of ginkgo extracts, including disrupted menstrual cycles, reduced ovarian follicle counts, embryo resorption as well as failed implantation in the uterine wall and impaired viability. Other experiments have reported that ginkgo flavonoids significantly increased the weight of the ovaries; the consequence of this on reproductive function is currently unknown.

Overall, the literature on ginkgo is confusing. Gingko extracts can both up- and down-regulate female reproductive processes. The effect of gingko depends upon the specific contents of each extract, which can vary substantially. Some ginkgo extracts were toxic to both healthy and cancerous ovarian cells. The ginkgolide B extract increased the death of fertilized embryos in mouse studies. Other extracts had the opposite effect on proliferation. The ginkgolide B extract also suppressed oocyte maturation, fertilization, and embryonic development by decreasing the number of cells in the embryo.

Ginkgo extracts often contain natural phytoestrogens that negatively affect reproductive steroid hormones and/or their receptors. Giving menopausal women Ginkgo biloba extracts increased testosterone and decreased sex hormone levels in plasma. Experiments have demonstrated a direct action of ginkgo extracts on ovarian hormone production and inhibited the release of progesterone.

Overall, ginkgo extracts have been shown to negatively affect female reproductive functions. Women may want to avoid nootropic pills containing ginkgo.