There’s hormones in beef? MSU Extension addresses common misconceptions

Beef has a low concentration of hormones when compared to other common foods in our diet, including vegetables. Even with the use of hormones from ear implants, beef still has lower concentrations of hormones than many foods in our diet.

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Product marketing has advanced drastically in the last couple of decades, to the degree it has now become a social science and art when it comes to studying consumer purchasing behaviors and decision-making. As a result, product marketing is very competitive as sellers try to gain an edge over their competitors to receive additional income or sales. Aside from the fancy colors, pictures and packaging, informative phrases and wording are another way to persuade the consumer to purchase one product over their competitor’s product.

When talking about beef, what do phrases such as, “raised without the use of hormones” or “no hormones administered” really mean and what do they imply?  With consumers being further removed from the farm, often these phrases can create a sense of confusion and fear for consumers, thus encouraging them to purchase the product with these label claims. This article will focus on hormone labeling claims as they pertain to beef products.

Hormones are signaling molecules naturally produced in all multicellular organisms (e.g., humans, animals, plants) that regulate physiological and behavioral responses. Humans have naturally occurring concentrations of hormones circulating in their body. Table 1 shows the naturally occurring production of estrogen in humans per day. Blood serum estradiol concentrations are low for pre-pubescent children ranging from 2 to 5 picogram (pg)/milliliter (ml), (a picogram is one-trillionth of a gram) typically ranging between 20 to 40 pg/ml for men and can vary considerably for women from 40 to 400 pg/ml, with post-menopausal women having lesser concentrations ranging from 5 to 20 pg/ml. Hormones concentrations also vary in cattle depending on sex and age.

Table 1. Natural Estrogen Production in humans (ng/day)

Pregnant Woman


Non-pregnant Woman


Adult Man


Pre-pubescent Children


* Preston (1997) Oklahoma Agri. Exp. Station Report

Hormones used in beef cattle production are used for two purposes. The first purpose is for improved reproductive management of breeding females in the cattle herd. Hormones (e.g., gonadotropin releasing hormone, prostaglandin) can be administered via intramuscular injections to cycling heifers and cows that are being prepared for breeding. These hormones help to synchronize the estrus cycles of the of the heifers and cows for easier breeding management. These female cattle are intended for producing next year’s calf crop and not the immediate beef supply.

The second purpose for using hormones in beef cattle production utilizes hormones via ear implants for improved rates of body weight gain, efficiency of feed required for weight gain, and leanness of growing steers and heifers raised for beef. Ear implants consist of pellets that contain hormones that are released at a slow rate over a designated period of time. Ear implants are typically administered with a strategic approach so the available hormone from the pellets is spent by the time of slaughter for maximum effectiveness. Currently, estrogen (e.g., estradioal-17β, estradiol benzoate, zeranol), progesterone and testosterone (e.g., trenbolone acetate) are used. Additionally, melengesterol acetate (MGA) is a progesterone-like feed additive that is used to suppress estrus, resulting in a greater rate of body weight gain and feed efficiency, in heifers intended for breeding or being fed for slaughter.

Ear implants have been approved for safe and effective use since 1956 by the U.S. Food and Drug Administration (FDA). The FDA has established safe maximum tissue residue levels for these hormones. The United States Department of Agriculture Food Safety and Inspection Service (USDA FSIS) regularly monitors and tests for potential contaminants in meat products to ensure food safety. For an additional measure of safety, implants are administered in the ear, which is discarded at slaughter and not allowed to enter the food supply.

Table 2 illustrates the estrogenic activity of several common foods, including beef from non-implanted and implanted steers or heifers. Maybe surprising to some, the estrogenic activity of beef from steers or heifers that received an ear implant is only slightly greater than that of non-implanted cattle. There are numerous foods that contain much greater concentrations of estrogen than beef from implanted cattle. Hormones consumed within our diet have a relatively low bioavailability, with less than 10% of estradiol being absorbed, due to gastrointestinal and liver inactivation in the body.

Table 2. Estrogenic activity of several common foods (ng/500g of food)

Soybean oil




Wheat germ






Ice Cream




Beef from pregnant cow/heifer


Beef from implanted steer/heifer


Beef from non-implanted cattle


* Preston (1997) Oklahoma Agri. Exp. Station Report

Overall, the use of hormones from ear implants has little effect on the hormone concentration found in beef. In fact, beef already has a relatively low concentration of hormones when compared to other common foods in our diet, including vegetables. The bioavailability of consuming hormones at this level (nanograms) is extremely small in comparison to the daily production of hormones our bodies naturally produce. If you are looking for more information on this topic, look up this other resource on hormone labeling claims, or you can reach out to me to discuss this topic further. The Michigan State University Extension Beef Team is a great resource for all your beef cattle and beef needs.

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