Xenoestrogens - Endocrine Disruptors / "Gender-benders"


What are xenoestrogens?
Endocrine disruptors
Xenoestrogens (sometimes referred to as “gender-benders”) are molecules with a structure very similar to that of natural estrogen.   Our modern day environment is rife with these estrogen “look-alikes”, which demonstrate an estrogenic effect in the body, by either / or:
- Mimicking the effect of estrogen;
- Indirectly affecting the body’s estrogen levels by disrupting the way estrogen is produced or used in the body.
“In the Columbia River, a recent study found that about 25 percent of the otters and muskrats were anatomically deformed.Estrogenic pollution kills birds, panthers, alligators, old men, young women, fish, seals, babies, and ecosystems.Some of these chemicals are sprayed on forests by the U.S.Department of Agriculture, where they enter lakes, underwater aquifers, rivers, and oceans.Private businesses spray them on farms and orchards, or put them into the air as smoke or vapors, or dump them directly into rivers.Homeowners put them on their lawns and gardens.”
“The Dire Effects of Estrogen Pollution” by Ray Peat, PhD.
The extent to which xenoestrogens have infiltrated our lives is nothing short of shocking! – – –
They are found in:Â fertilizers, herbicides, pesticides, insecticides, dairy products, meat, fish, pharmaceuticals, cosmetics and personal products (a major source for women, especially in things that touch the skin i.e. lotions, shampoos, soap), squeezable toys, baby bottles, industrial effluent and by-products, car exhaust and more. They are leaching into canned foods and many foods packaged in plastic, and they exist in water, soil and air.
Xenoestrogens wreak havoc with the body’s delicate hormonally balanced endocrine system
Xenoestrogens are implicated in numerous health problems – including:
- Infertility – due to high estrogen levels in both sexes, reduced TESTOSTERONE/sperm counts
- Erectile dysfunction (Viagra is a $1 billion business)
- Deformed reproductive organs
- Endometriosis
- BPH (prostate enlargement)
- Male breasts and other reproductive abnormalities
- Cancer of the breast, uterus, testes and prostate
- Immunodeficiency
- Obesity
- Chronic fatigue

How do xenoestrogens exert their effect?
Although similar, xenoestrogens are not identical to natural estrogen and have a different effect – a hormone binds to its associated receptor on a target cell (much like a key in a lock) to do a specific and complex job. If the molecular structure is different, even by one atom, the instructions given to the cell are different.
- Xenoestrogens can mimic or block hormone messages with the same, weaker, or stronger responses – by docking (binding) to an estrogen receptor and mimicking or blocking normal estrogen response.
-  Disrupting normal estrogen metabolism by operating independently of the hormone receptor:
- They can prevent or promote estrogen from being made, broken apart, or carried in the bloodstream (by attaching to estrogen transport proteins (Sex Hormone Binding Globulins or SHBGs) – and pushing off the natural estrogen so it doesn’t reach its target).
- They can change hormone production and disposal by interrupting enzyme relay systems inside cells or by stimulating or slowing CYP enzyme production, to change the natural estrogen balance. Cytochrome P450 enzymes (CYPs) are involved with the production and breakdown of all steroid hormones (e.g. estrogens, androgens, progestins)
Natural hormones are subtly balanced and need only miniscule amounts to function.    In particular, estrogen is delicately opposed by PROGESTERONE in the body and natural PROGESTERONE is no match for invading synthetic, “foreign” estrogens
Synthetic xenoestrogens are not easily broken down and can accumulate and be stored in the body’s fat cells, including breast fat. The daily intake of even small amounts of xenoestrogens accumulate and bind to estrogen receptor sites, unbalancing the endocrine system with devastating health consequences.

Shocking sources of xenoestrogens
Xenoestrogens ion our diet and environment contribute to estrogen dominance
Food meats and produce
Meat, fish and dairy are a significant and accumulating source of xenoestrogens.     Food eaten by fish, poultry, animals or humans may contain xenoestrogens – stored in their fat, flesh, and milk in increasing concentration, as they are stored in the body faster than they are broken down or excreted, until they reach the top of the food chain – i.e. Us !
Commercially raised meat and dairy products contain large amounts of xenoestrogens. Â
- Estrogenic growth hormones are commonly injected into and fed to livestock to make animals grow faster and gain weight by retaining water.
-  The dairy industry uses  rBGH (recombinant bovine growth horomone) or rBST to force cows to produce more milk;
- Estrogenic insecticides are applied directly to the animals (often automatically).
Pesticides / herbicides on plant food.   Pesticides/herbicides sprayed on grain, vegetables and fruit (sometimes many times /season) contain xenoestrogens, E.g. dioxin (an organochloride – a by-product of chlorine processing); DDT and Polychlorinated biphenyls (PCBs); Although now banned, DDT and PCB residues still persist in soils.
Sewage sludge
The U.S. Environmental Protection Agency (EPA) states that ~50% of U.S. Sewage sludge is recycled onto the land for fertilizer
“Biosolids” (the PR version) are what’s left over after sewage is treated and processed – not just from human waste, but from every time a paintbrush gets rinsed, an old bottle of medications is flushed, or solvents are hosed off a factory floor. Ironically, this recycling into food crops began when it was realized that dumping them into rivers, lakes and bays was an environmental hazard! As a poignant example of xenoestrogen contamination via this route, consider that excretions of women using birth control pills and hormonal replacement therapy can “recycle” back to us in our food and water. Effluent from sewage plants are returned to the environment, where, through run-off, they end up back in our water supply (water treatment plants are not designed to remove hormones).Also, sewage spillage directly into waterways is not uncommon -The New York Times reported in 2009 that in the previous three years more than 9,400 of the 25,000 U.S. sewage systems had violated the law by dumping untreated or partially treated human waste, chemicals and other hazardous materials into rivers, lakes and other waterways.
- In 1988, an Environmental Working Group analysis of sewage sludge found >100 synthetic organic compounds (E.g. phthalates, toluene, chlorobenzene), 80% of systems contained dioxins, 42 different pesticides (averaging 2/sample), 9 heavy metals (often high concentrations) http://www.ewg.org/research/dumping-sewage-sludge-organic-farms. Sewage sludge was blamed for some of the lead contamination of the White House lawn and Michelle Obama’s organic veggie garden.
- The Center for Food Safety (CFS) petitioned the city of San Francisco to stop distributing sewage sludge (PR term is “organic compost”) to homeowners and schoolyards, given that in 2008, its sludge was found to contain industrial chemicals, disinfectants, phenol, pesticides and solvents.
Water from Sewage treatment plants is tainted with chemicals.    With cleaning solutions, personal care products, and natural and synthetic hormones.
Birds, panthers, turtles, fish, alligators have shown alterations in sex characteristics.  For more than 10 years, researchers worldwide have observed that fish in our lakes and rivers are actually switching gender due to their high levels of polluted effluent estrogens and/or industrial xenoestrogens – The most publicized study concerned alligators in Lake Apopka, Florida, after a pesticide, now known to be a powerful xenoestrogen, was spilled into the lake. The male gators’gonads shrank and there was a marked decrease in the local gator population because of their inability to reproduce. Even more shocking – in the Potomac River, and many other areas in the U.S. male smallmouth bass have been found laying eggs!    Science Daily, 2008
- Livestock feedlot effluent is another source of aquatic hormonal contamination.
A staggering HALF of all male fish in British lowland rivers have been found to grow eggs in their testes  2009 ChemTrust report
Plastics
“I want to say one word to you. Just one word. . . Plastics!”   When this one word of career advice was given to “The Graduate” in the classic 1963 movie, no-one could have imagined the impact plastics were going to have on our world . . .
Different types of plastics are identified by number to enable you to make better choices when shopping: | ||
![]() | Polyethylene terephthalate (PET or PETE) | Soft drink bottles, medicine containers, cooking oil bottles, peanut butter jars; |
![]() | High density polyethylene | Toys, bottles/jugs for milk, water, detergent, shampoo, motor oil |
![]() | Polyvinyl chloride (V or PVC) | common in plastic pipes, meat wrap, cooking oil bottles, outdoor furniture, siding, floor tiles, shower curtains, clamshell packaging; |
![]() | Low density polyethylene | Wrapping films, grocery bags, Some bread and frozen food bags and squeezable bottles, produce bags, trash can liners, dry-cleaning bags. |
![]() | Polypropylene | Syrup bottles, yogurt containers, diapers, some ketchup bottles and margarine tubs, bottle caps, drinking straws; |
![]() | Polystyrene | Products: Coffee cups, clam-shell take-out containers, packing peanuts, plastic cutlery, meat trays; BTW, there is no such thing as a “Styrofoam cup”-Styrofoam is a trademarked material made by the Dow Chemical Company, but they do not make cups, plates, egg-cartons or any food packaging from it. |
![]() | Usually polycarbonate | Medical storage containers, some Nalgene water bottles, Tupperware, baby bottles |
Unfortunately, along with their benefits, plastics have also introduced us to some seriously harmful xenohormones, especially xenoestrogens:
Phthalates / “Plasticizers”
Used to soften #3 PVC plastic into its flexible form, and to add transparency, durability, and longevity. Manufacturers add various toxic chemicals known as “plasticizers” during production. One of these chemicals is a xenoestrogen, known as phthalate, and can leach out of PVC in trace amounts, even more so in the presence of heat.On contact or when heated, trace amounts of phthalates can leach into food from PVC-based containers and wrap, particularly when the food is oily or has a high fat content. Of considerable concern, studies have revealed that phthalates exposure can also be via the skin or mouth through dust and air. http://www.environmentalhealthnews.org/ehs/newscience/indoor-measure-of-airborne-contaminants/
- Phthalates have been found at high concentrations in human plasma and urine.  Swan et al. 2005
- Phthalates are released from source by heat, agitation, and prolonged contact/storage
- Phthalates can cross the placenta
- DEHP (di-(2-ethylhexyl) phthalate) is the most abundant environmental phthalate.    Chronic exposure to low, environmentally relevant DEHP levels increased serum concentrations of TESTOSTERONE and ESTRADIOL by >50% – by inducing high levels of gonadotropin LH (luteinizing hormone). Benson T et al, Phthalate-induced Leydig cell hyperplasia is associated with multiple endocrine disturbances, PNAS, 2004
- Cling-wraps.   Originally PVC-based, but due to health concerns, brands including Glad Cling Wrap, Handi-Wrap and Saran Premium Wrap (newer version of Saran Wrap) are now LDPE.HOWEVER, food caterers still prefer to use PVC-based wrap – since it is generally more clingy, not so permeable to oxygen, aroma, and flavor, and more resistant to freezer burn.
- Phthalates are found in:Â Â PVC plumbing pipes, irrigation systems, PVC-based cling wrap, flexible plastic kitchen utensils and microwave ovenware, medical tubes and devices, processed food packaging, plastic shower curtains, vinyl flooring and wall coverings, nail polish, hair spray, shampoo, deodorants, fragrances, toys;
Bisphenol A (BPA)
A building block of rigid #7 plastic polycarbonates and epoxy resins. BPA is a xenoestrogenic chemical invented during the search for synthetic estrogens in the 1930’s.Many studies confirm BPA as a hormone disruptor, even though it has a potency ~ 10,000 times less than pure estrogen.
Type 3 PVC can contain BPA as an antioxidant in plasticizers.
What products contain BPA?
- Polycarbonate plastic.   Rigid, clear and nearly shatter-proof, polycarbonate is used to make:
- BPA-containing epoxy resins coat the inside of almost all food and beverage cans and boxes.   Acidity increases BPA-leaching into food.E.g. canned tomatoes have higher BPA levels than other non-acidic foods. The linings of canned food-linings are our largest exposure source. BPA contamination researcher Laura Vandenberg, PhD, postdoctoral fellow in biology at TuftsUniversityin Boston
For clarification, Types 1, 2, 4, 5 and 6 plastics do NOT use BPA during production (polymerization) or package-forming.
Some examples of BPA health effects
- Adverse effects on pregnancy.    A 2009 in vitro study on cytotrophoblast cells has found cytotoxic effects in exposure of BPA doses from 0.0002 to 0.2 µg /ml and concluded this finding “suggests that exposure of placental cells to low doses of BPA may cause detrimental effects, leading in vivo to adverse pregnancy outcomes such as pre-eclampsia, intrauterine growth restriction, prematurity and pregnancy loss” Effects of Neonatal Exposure to Bisphenol A on Steroid Regulation of Vascular Endothelial Growth Factor Expression and Endothelial Cell Proliferation in the Adult Rat Uterus, Biol Reprod January 2010
- Low doses promote breast cancer cells in vitro.   In 1993, a Stanford university school of medicine team found that 2-5 parts per billion of BPA was enough to cause breast cancer cells to proliferate in vitro.
- In 1998, an Environmental Health Perspectives (EHP) study found that BPA simulates the action of estrogenwhen tested in human breast cancer cells.    A more recent study published in EHP shows a significant decrease of TESTOSTERONE in male rats exposed to low levels of BPA.
- BPA has more potent effects at certain times in the life of an organism and lower doses produced greater effect than low doses.    A study in Environmental Health Perspectives reveals that BPA is particularly potent in mice exposed near the time of birth. Pregnant female mice exposed to low levels of BPA near the time of birth produce offspring that gain excessive weight early in life and maintain excessive weight thereafter. This effect does not occur in mice fed BPA as adults. (The study also found that low doses of BPA produced a greater effect than higher doses). According to the authors of the study, their BPA data “suggest the need for careful evaluation of the current levels of exposure [of humans] to this compound.”    EHP Vol. 109, No. 7 (July 2001), pgs. 675-680
Estimated DAILY intake of BPA by U.S. Dept of Health and Human Services
- Adult 0.008-1.5 μg/kg (135# adult intakes an average 46 μg BPA/day);
- Child (1½-6 yrs) 0.043-14.7 μg/kg;
On average, humans ingest ~ 6.3 µg / day of BPA just from the linings of food cans!
In 2009, more than 6 billion pounds of BPA was manufactured.    These provided nearly $7 billion in sales. US companies that make BPA are Bayer Material Science, Dow Chemical Company, SABIC Innovative Plastics (formerly GE Plastics), Hexion Specialty Chemicals, and Sunoco Chemicals.
Metalloestrogens
What are metalloestrogens?   Metalloestrogens are organic xenoestrogens, which can affect the gene expression of human cells responding to estrogen. Metalloestrogens have shown affinity for estrogen receptors, and can thus mimic estrogen activating the receptor. They are considered harmful and potentially linked with breast cancer.
Include:Â Â aluminum, antimony, arsenite, barium, cadmium,chromium (Cr(II)), cobalt, copper, lead, mercury, nickel, tin, and vanadate.
NPEs
NPEs (Nonylphenol ethoxylates).    In many common household products, (carpets, furniture, drapes) commonly used as detergents in many industrial processes (E.g. Production of oil/pulp/paper, synthetic/natural textiles and leather), additives in latex paints and cosmetics, antioxidants/stabilzers in some plastics and pesticides.

Why has estrogen dominance become so prevalent?
Chart of Xenoestrogen sources |
|||
---|---|---|---|
“X-Rated” Products (i.e. contain Xenoestrogens) | Xenoestrogens | ||
General Household | ![]() ![]() ![]() ![]() |
Phthalates / DEHP (Plasticizers that soften #3 PVC) – released from source by heat, agitation, prolonged storage; BPA (antioxidant in plasticizers); NPE (nonylphenol ethxylates) (antioxidant/stabilizer); Cadmium (stabilizer) | |
CDs and DVDs, and household electronics. | BPA | ||
Electronics; Nickel-cadmium batteries – the EU banned most cadmium use in electronics in 2004. A few exceptions allowed 0.002%. | Cadmium | ||
Carpets, furniture, drapes | NPE; formaldehyde | ||
Gore-tex | PFOAs | ||
Cleaning chemicals:Â detergent, fabric softener, bleach, dry-cleaning chemicals; air-fresheners. | BPA; Phthalates (fragrances) | ||
Extermination Products | Pesticides /herbicides | PCB, DDT, Dioxin, NPE (antioxidant) | |
Fungicide | vinclozin | ||
DDT breakdown product | butylated hydroxyanisole / dichlorodiphenyldichloroethylene | ||
Weed killer E.g Lawn Weed ‘n’Feed | Atrazine | ||
Insecticides / insect repellants | Dieldrin, DDT, endosulfan, heptachlor, lindane / hexachlorocyclohexane, methoxychlor | ||
Cosmetics | Applied directly to the skin, xenoestrogens are up to 10 times more potent than those taken orally because they travel directly to the body’s tissues instead of passing through the liver. | Sunscreen lotions | 4-MBC (4-Methylbenzylidene camphor) |
OFTEN in: Facial/Body lotion, sunscreen, shampoo, conditioner, deodorant, make-up, nail polish/remover, hair spray/gels, soap, make-up. In an estrogen receptor-binding assay, butylparaben was able to compete with the female hormone ESTRADIOL for binding to estrogen receptors with an affinity ~ 1/5 of the highly toxic synthetic estrogen diethylstilbestrol (DES), which was the first hormone to be used by the meat industry to fatten livestock, until it was discovered that it causes cancer even in extremely minute amounts. | Parabens (methyl-, ethyl-, propyl-, butyl-); E216(preservatives); Phthalates (makes fragrance last longer; helps lubricate other substances); NPE (in some cosmetics) | ||
Workshop | Electrical, oils, lubricants, adhesives, paints; | PCBs | |
Plywood, Fiberglass | Formaldehyde | ||
Latex paint additive | NPE | ||
Biocide and wood preservative | Pentachloriphenol | ||
Food | ![]() ![]() |
Phthalates | |
 ![]() ![]() |
BPA | ||
Epoxy resins coating the inside of almost all food and beverage cans and boxes. | BPA | ||
Dairy | Dieldrin, DDT, rBGH | ||
Teflon-coated pans (especially if overheated) | Perfluoroalkyl compounds (PFOAs) | ||
FD&C Red No. 3 | Erythrosine | ||
Food preservative | BHA (butylated hydrooxyanisole) BHT | ||
Some flavorings | Phthalate | ||
Processed food products – contain traces of xenoestrogens from solvents used to clean food processing equipment | BPA | ||
Product oils/fats – protected by xenoestrogenic antioxidants | Propyl gallate | ||
Fatty, salty, or acidic (lemon juice, vinegar wine, tomato sauce) foods packed or stored in type 3 or 7 plastic containers – increase leaching of phthalates and BPA | PhthalateBPA | ||
Medical | Contraceptive spermicides / treated condoms | Nonoxynol-9 (form of NPE) | |
Combined oral birth control pill (released into environment) | EthinylESTRADIOL | ||
A red dye used in tissue culture media as a pH indicator | Phenosulfothiazine | ||
#3 PVC-based and #7 Polycarbonate:Â dental devices, dental fillings and sealants, eyeglass lenses, medical tubes/devices(e.g. blood bags, hemodialysis tubing, and nasogastric feeding tubes) | Phthalates, BPA | ||
DES -from 1940-1970, this notorious synthetic estrogen was given to pregnant women to reduce risk of pregnancy complications; human studies revealed that its use during pregnancy not only caused cancer, miscarriages, blood clots, etc., in the women who used it, but also caused cancer, infertility, and deformities in their children, and even their grandchildren! | DES (diethyl stilbestrol) | ||
Industrial Manufacture | Industrial surfactants; Emulsifiers for emulsion polymerization; Detergents in many industrial processes (E.g. Production of oil/pulp/paper, synthetic/natural textiles and leather). | NPE (nonylphenol ethxylates); Octaphenol compounds | |
Intermediate chemicals used in the manufacture of other chemicals. | Alkylphenols |