Research & Commentary: Endocrine Disruptors

Published June 2, 2014

Like all other multicellular organisms, human beings have endocrine systems. Also called the hormone system, the endocrine system is a collection of glands that secrete hormones (regulatory biochemicals) that enter the bloodstream or other cellular fluids and search for cells with compatible receptors. Once a hormone has found and bound to a compatible receptor, the cell will react by altering its proteins or building new ones.

Through that process, the endocrine system regulates many familiar biological functions such as metabolism, blood sugar levels, and the development of the brain, nervous, and reproductive systems.

In our daily lives, humans encounter many substances—both natural and artificial—that can interact with our endocrine system. Many environmental activist groups refer to these substances as “endocrine disruptors.” But such a term is widely misleading, because not all changes in the endocrine system produce adverse effects, and both natural and synthetic chemicals can interact with the endocrine system without “disrupting” anything.

Among the chief targets of complaints about so-called endocrine disruptors are the chemicals in everyday plastics. However, Ronald Bailey of the Reason Foundation notes humans have been living longer and suffering fewer disabilities even while our use of plastics has increased. Instead, Bailey suggests a simpler hypothesis for the increase in various diseases including several cancers: obesity, which is positively correlated with many of the same diseases often cited in arguments against endocrine disruptors. Obesity is also negatively correlated with testosterone levels, an affect also often misattributed to endocrine disruptors.

From 1970 to 2000, Americans’ daily caloric intake increased by nearly 25 percent, and it has since remained stable at those 2000 levels. Greater caloric intake combined with an increasingly sedentary lifestyle has been a major reason the Journal of American Medicine says more than one-third of U.S. adults are obese.

Scientific evidence is clear that eating too much and exercising too little will have adverse health effects, whereas the scientific evidence shows endocrine-affecting chemicals generally do not have such effects. More than 5,400 journal articles have been published on the safety of low levels of Bisphenol A, or BPA, perhaps the most high-profile endocrine-affecting chemical. This underscores the point made by the American Chemistry Council, that the “presence of a substance that has adverse effects at some level does not imply that the presence of that chemical will lead to adverse effects at all levels.”

When science shows no damage from use of chemicals at normal levels, governments should allow consumer choice and other market mechanisms to regulate the use of chemicals in industrial products and avoid implementing their own regulations, which would be economically costly while deflecting attention from more serious problems.

The following documents provide additional information about endocrine disruptors.


Ten Principles of Energy Policy
Heartland Institute President Joseph Bast outlines the ten most important principles for policymakers confronting energy issues, providing guidance to help deal with ongoing changes in markets, technology, and policies adopted in other states, supported by a thorough bibliography. 

Endocrine Primer
The U.S. Environmental Protection Agency (EPA) offers a primer on the human endocrine system, explains what endocrine disruptors are, and describes the Endocrine Disruptor Screening Program and how it’s implemented. 

Chemicals and Endocrine Disruption
The American Chemistry Council offers a brief introduction on endocrine disruptors and how the term can sometimes be wrongly conflated with any substance that affects endocrine activity, good or bad. 

Environmentalism at Wit’s End: A Review of Pandora’s Poison
In a February 2000 paper for The Heartland Institute, Heartland President Joseph Bast reviews a book by Greenpeace activist Joe Thornton, Pandora’s Poison: Chlorine, Health, and a New Environmental Strategy. Thornton’s book argues modern toxicology and epidemiology lack the tools to protect humans from dangerous manmade chlorine-based chemicals and calls for the immediate “sunset” of their commercial use. Bast criticizes Thornton for making several false assumptions, attacking scientists’ integrity, and trying to hide a dubious political agenda. 

Bisphenol A (BPA): Use in Food Contact Application
The U.S. Food and Drug Administration (FDA) gives an overview of Bisphenol A (BPA), a well-known endocrine disruptor present in many household plastics. FDA verifies that studies “employing standardized toxicity tests have thus far supported the safety of current low levels of human exposure to BPA.” FDA also affirms its scientists have reviewed “hundreds of studies” that further attest to its safety. 

Kristof Over the Top on Chemicals
Dr. John C. Goodman of the National Center for Policy Analysis highlights a New York Times column writer spreading alarm over household chemicals, and the response of Dr. Gilbert Ross of the American Council on Science and Health, who strongly disagreed with the column. Ross notes many of the chemicals mentioned in the column have been used safely for decades, and stories of gender-bent frogs and declining sperm counts have been thoroughly discredited. 

‘Intuitive Toxicology’ and Panicking Over Plastics at The New Republic
Ronald Bailey of the Reason Foundation responds to a writer’s scapegoating of numerous chemicals she claims are responsible for the proliferation of several diseases. Bailey finds the asserted links between endocrine disrupting-chemicals and growth in major diseases have been highly speculative and lacking in real evidence. Instead, life expectancies and the number of disabilities have decreased since the use of plastics has risen. Bailey also cites a study that found “average exposures to Bisphenol A is about one-thousand times less than the levels determined by the EPA to be safe for daily exposures. Similarly, the study found the average exposures for the general population to phthalates are below levels determined by the EPA to be safe for daily exposures.” 

Raising Up the BPA Boogeyman Yet Again: A Scientific Disgrace
Writing for, Interscan Corporation Executive Vice President Michael D. Shaw argues ongoing perpetuation of fears of BPA is both a distortion of and disgrace to science. In reality, Shaw notes, BPA has been extensively studied and evaluated and proven safe. 

The Top 10 Unfounded Health Scares of 2012
The American Council on Science and Health ranks the top ten health scares of 2012 that had little to no scientific basis. Ranked number ten was Bisphenol A (BPA), a well-known household chemical alleged to disrupt proper hormone function when absorbed in the body. ACSH notes there is no scientific evidence showing BPA to be anything but safe, and that replacing BPA with lesser-known, less-scrutinized chemicals would actually increase the risk of health effects. 

The Newest ‘Endocrine-Disruptor’ Can Be Found in Your Backyard, Claims a New York Times Op-Ed
The American Council on Science and Health responds to a New York Times op-ed painting endocrine disruptors as serious threats to public health and the environment. As the ACSH points out, the term “endocrine disruptor” merely refers to chemicals that bind to hormone receptors, many of which do so without “disrupting” anything.

Adult Obesity Facts
The Centers for Disease Control and Prevention outline the prevalence of obesity among U.S. adults as a whole, as well as in individual states and socioeconomic categories.


Nothing in this Research & Commentary is intended to influence the passage of legislation, and it does not necessarily represent the views of The Heartland Institute. For further information on this and other topics, visit the Environment & Climate News Web site at, The Heartland Institute’s Web site at, and PolicyBot, Heartland’s free online research database, at

If you have any questions about this issue or The Heartland Institute, contact Heartland Institute Policy Analyst Taylor Smith at [email protected] or 312/377-4000.