What are Metalloestrogens

Originally Published on Chemical of the Day, September 2014.

We talk a lot about hormone-disrupting chemicals: parabens, pthalates, phenoxyethanol. But the risks of these chemicals may be overshadowed by a potentially more harmful class of chemicals that not as many people know about: metalloestrogens. Many common metals have been found to mimic estrogen or interfere with hormone function in the body. There is still much to be learned about the mechanisms whereby they act, however, research is uncovering much about these metals' roles in diseases such as breast cancer and endometriosis.

Potential estrogen mimickers like parabens actually pass through the body fairly quickly, with most of the substance being metabolized wtihin a day or so and flushed out through urine. (Now, of course, in order to metabolize the parabens, the body has to use estrogen sulfotransferase enzymes, which are then not doing their original job of flushing out estrogen, thus possibly leading to increased estrogen levels.) So, when you stop using parabens, you're detoxed from them fairly quickly. But with metalloestrogens, the body has a much harder time at removing them. They are metals, after all. Some metals will stay in the body for 10 to 30 years.

Now, here's where it gets more complicated. Some metalloestrogens such as chromium, cobalt, copper, and nickel are actually essential minerals that our bodies need in trace amounts for enzymatic and other functions. However, if the concentration of these metals become too high, they can actually interfere with enzymes, or even cause cancer. (Chromium and nickel are known carcinogens). Then, there are nonessential metals such as lead, aluminum, mercury, and cadmium that have no function in the body and end up blocking the function of essential metals and hormone receptors, leading to disease.

Here are a few common metals that are suspected to display estrogenic effects:


For more on the dangers of aluminum, see my previous article. The bottom line--no matter the form (aluminum chlorohydrate, potassium alum, etc) aluminum has the ability to bind to hormone receptors and interfere with hormone balance. Aluminum has been linked to breast and other reproductive cancers. (Source)

Found in: antacids, antiperspirants, crystal deodorants, cookware


Chromium is an essential nutrient the body needs to function, however, in excess amounts it can cause toxic effects. There are many types of chromium. The two most common forms are chromium 3+ (the biologically active form) and chromium 6+ (found in industrial pollution.) The body is able to convert chromium 6+ in to the less harmful 3+ form, however, when it does, the overall level of chromium iii in the body is increased. Animal studies have found it to affect reproductive function and create ovarian toxicity in animal tests. (Source) (Source)

Found in: drinking water, steel, cars, paints, treated woods and leathers.


The potential estrogenic effects of lead are still largely under-studied, however, more is being uncovered about this harmful heavy metal. This study found that breast cancer cells proliferated when treated with a solution of lead. This study found that women with higher blood levels of cadmium and lead were more likely to suffer from uterine fibroids.

Found in: older paints, varnishes, plates and cups, foods, water, mineral pigments


Cadmium exposure primarily occurs through dietary sources and cigarette smoking. It can stay in the body for 10 to 30 years. Smokers have been found to have twice the concentration of cadmium in their system than non-smokers. (Source)

"Our data may suggest that Cd interferes with the levels of testosterone and estradiol in postmenopausal women, which might have implications for breast cancer risk." (Source)

In this study, cadmium was able to proliferate the growth of cells responsible for endometriosis.

(Interesting: melatonin found to help inhibit the action of cadmium here.)

Found in: this abundant element in the earth's crust can be found anywhere at low levels. However, it can be found in concentrated amounts as an industrial pollutant in soil and groundwater.


Mercury has been found to stimulate breast cancer cells in lab tests. (Source) Levels of cadmium, lead, and mercury have also been found to lead to anovulatory cycles in women. (Source)

Found in: fish, dental amalagams

Other metals with potential estrogenic effects: selenite, tin, vanadate, cobalt, copper, nickel, antimony, arsenite, barium

What Now?

If you have eliminated parabens, pesticides, plastics, and other commonly known estrogen mimickers from your life as much as possible and are still suffering from reproductive disorders such as fibroids, endometriosis, PCOS, infertility, or even fibromyalgia or lupus, you may have a heavy metal toxicity. The best way to test for heavy metals is hair testing (can be done in conjunction with blood testing) which can be done in select holistic practitioner's offices. If you do have a heavy metal toxicity, there are different treatment methods (herbs, chelation, dietary changes) that can help you remove these metals that are wreaking havoc on your body. These treatments should be done under the careful watch of a qualified healthcare pofessional, as the release of these compounds in to the bloodstream from other tissues can have side effects, and you also should be monitored to make sure that other vital minerals are not being stripped through your detox.

Additional Sources:

27th Aug 2021

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