In 2002, the World Health Organization’s (WHO) International Program on Chemical Safety (IPCS) proposed the following definition of an endocrine disruptor that is still widely accepted today:“An endocrine disruptor is an exogenous substance [a substance coming from outside the body] or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny, or (sub)populations.” This internationally accepted definition of an endocrine disruptor has two very important pieces:
- first, that the substance alters the function of the endocrine system and
- second, by doing so, it must lead to an adverse health effect in a living organism
No cosmetic ingredient would be classified as an endocrine disruptor under the WHO definition. This definition for endocrine disruption should not be confused with endocrine activity. Many natural and man-made chemicals can and do interact with the endocrine system, or are endocrine-active.” Endogenous endocrine activity by itself is essential for a healthy life. An increase or decrease in activity does not imply a health risk to a living organism, unless it can be shown to lead to harmful effects. Many endocrine active substances may lack sufficient potency (compared to the body’s natural hormones), or exposures may be so low that no effects occur at all. In other cases the body naturally adjusts, and the exposure causes no health effect.
The endocrine system is found in all humans and many other animals. The endocrine system is made up of 8 major glands – the pituitary, hypothalamus, pineal, thyroid, thymus, pancreas, adrenals and the testes (male) or ovaries (female). Each gland secretes different types of hormones, or chemical messengers, into the bloodstream to activate cellular targets that control, among other things: growth and development, cellular metabolism and tissue function, sugar levels, sexual function and reproduction, and sleep and mood. Estrogens (for example estradiol) are a group of steroid compounds, named for their importance in the menstrual (i.e., estrus) cycle and function as a primary female sex hormone. Estrogens are used in some contraceptives and in estrogen replacement therapy of postmenopausal women. Testosterone is an androgen hormone that is associated with the development and function of male properties in humans.
See more on the endocrine system.
No, there is no convincing evidence that ingredients used in cosmetic and personal care products cause endocrine disruption in humans. Many substances, both naturally occurring and man-made, may have some potential to mimic natural hormones under laboratory conditions. For example, plant estrogens (also known as phytoestrogens) found in soybeans, cabbage, sesame seeds, red wine and other foodstuffs have been shown to have weak endocrine activity. However, the estrogenic activity of these materials, as measured under laboratory conditions, is generally far below that which is observed for estradiol – the naturally occurring form of estrogen in the human body. And your body cannot tell the difference between natural or man-made substances. In addition, the levels at which ingredients with potential hormonal properties occur in cosmetic and personal care products is significantly below levels that have been associated with the laboratory demonstrated endocrine activity.
The Food and Drug Administration (FDA) has evaluated studies that have alleged potential endocrine effects for some cosmetic ingredients and has concluded that there is no reason for consumers to be concerned. Parabens is one such example. Although some parabens can act similarly to estrogen, they have been shown to have much less estrogenic activity than the body’s naturally occurring estrogen. A 1998 study (Routledge et al., in Toxicology and Applied Pharmacology) found that the most potent paraben tested in the study, butylparaben, showed from 10,000- to 100,000-fold less activity than naturally occurring estradiol. Further, parabens are used at very low levels in cosmetics and foods. In a review of the estrogenic activity of parabens, (Golden et al., in Critical Reviews in Toxicology, 2005) the author concluded that based on maximum daily exposure estimates, it was implausible that parabens could increase the risk associated with exposure to estrogenic chemicals. Based upon such evidence, FDA concluded that at the present time there is no reason for consumers to be concerned about the use of cosmetics and foods containing parabens.
In 1996, the U.S. Congress directed the U.S. Environmental Protection Agency (EPA), through the Food Quality Protection Act and amendments to the Safe Drinking Water Act, to develop a screening program for evaluating the potential of substances to induce hormone-related health effects to humans and other animals. Since then, the EPA has been in the process of validating endocrine disruptor screening and testing methods. The European Union has a large research program aimed at better understanding the question of endocrine disruption. The Japanese government as well as other countries are also sponsoring research in this area.
Industry, including cosmetic and personal care product manufacturers, has been working in collaboration with academic and government scientist to conduct research to determine whether low level substances interfere with naturally occurring hormones or with the normal function of the endocrine system to cause possible adverse health effects.
- Experimental screening studies are available that can identify substances that may be endocrine-active.
- Additional safety assessment protocols are available to show whether endocrine-active substances will cause any negative health effects in living organisms.
- Such studies have demonstrated that there is a safe exposure level below which endocrine active substances cause no adverse health effects.
- Current safety assessment practices carefully evaluate the potential for any cosmetic/personal care product ingredient to disrupt the endocrine system.