The facts about hormones and beef

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Questions exist in the public sector regarding the safety of consuming hormone implanted beef. In short, the use of supplemental hormones in beef production has been scientifically proven as safe for consumers and is approved by the US Food and Drug Administration (FDA). For those still in question, let’s further examine the science supporting these facts.

Hormones are products of living cells naturally found in both plants and animals that often stimulate cellular activity. There are six hormones approved for use in beef production. Three are natural hormones (testosterone, estradiol, and progesterone) and three are chemically similar synthetic hormones (melengestrol acetate, trenbolone acetate and zeranol).

Growth hormones in beef are primarily administered using a small pelleted implant that is placed under the skin on the back of the ear. The implants are designed to release the hormone slowly over time into the bloodstream. This ensures that hormone concentrations remain constant and low. Since the ear is discarded at harvest, the implant does not enter the food chain. Implants work by increasing the amount of growth regulating hormones, which are naturally produced by the animal. This, in turn, increases feed efficiency, protein deposition and growth rate. Implanted calves usually result in a 10-20% increase in average daily gain (growth rate) compared to non-implanted calves. Moreover, because of the increased feed efficiency, less feed is required which decreases production costs by 5-10%.

Since implant doses are low, the use of implants in cattle has very little impact on hormone levels in beef. Table 1 illustrates that 500 grams (~ 1 lb) of beef from an implanted steer contains approximately 7 nanograms of estrogen compared to 5 nanograms of estrogen from non-implanted beef. Furthermore, there are many common foods that are naturally much higher in estrogen than implanted beef. For example, 500 grams of tofu contains 16,214,285 times the amount of estrogen compared to the same amount of implanted beef. To gain additional perspective on the minuteness of these measurements, nanograms are equivalent to1 billionth of a gram. One gram is roughly equal in weight to 1 small paper clip. If we were to divide the same paper clip into 1 billion tiny pieces, one of those tiny pieces would equal 1 nanogram.

a Nanograms of estrogen per 500 grams of food.

Some consumers question whether consuming beef implanted with hormones can cause cancer or early puberty in children. Hormone implanted beef has never been implicated with adverse health effects in humans. However, height, weight, diet, exercise and family history have been found to influence age of puberty. Furthermore, the amount consumed in implanted beef is negligible compared to the amount the human body produces each day (Table 2).

Regarding potential environmental concerns associated with growth hormones, the FDA has determined that the use of natural hormones in beef does not pose a risk to the environment as the amounts administered to calves are much lower than amounts naturally produced by adult cattle. Regarding synthetic hormones, extensive environmental risk studies have been conducted and the FDA has determined that the use of these hormones will not significantly impact the environment.

Most of the beef produced in the US spend most of their lives in a pasture and are then finished in a feedlot where they are given a grain fed diet. Beef that are finished in a feedlot with the aid of growth hormones require less total land mass, less feed crops and create fewer greenhouse gasses per pound of  beef produced compared to non growth hormone pasture based finishing systems.

Consumers that prefer to purchase naturally produced or organic beef raised without growth hormones, should be prepared to pay a premium. Implanted beef reduce the cost and resources required in beef production and that results in lower costs that are passed on to the consumer.


Loy, D., 2011. Understanding hormone use in beef cattle Q&A. Iowa State University Extension. Available at:

Source: Dr. Josh Payne, Oklahoma State University Extension Area Animal Waste Management Specialist

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OKlahoma  |  September, 15, 2012 at 10:29 AM

Evidently it's the season to trot out an article fiercely defending the status quo, as this one is just another piece of boiler plate. From the argument mounted here shouldn't hormone implanted beef actually be sold at a discount because of the "increased" efficiency of production? BTW I'm a lifelong rancher who eats hormone free beef of my own raising, and not a nut-job like typically responds to articles like this one. At the end of the article I noticed the author was highly qualified to write this piece of tripe since he's a Animal Waste Management Specialist which translates into one who manages manure. Great job doc !

Iowa  |  September, 15, 2012 at 04:34 PM

"From the argument mounted here shouldn't hormone implanted beef actually be sold at a discount because of the "increased" efficiency of production?" ...ever look at the price difference between conventional wrapped beef and the stuff with "hormone free" stickers and labels all over it?

Indiana  |  September, 17, 2012 at 06:25 AM

Like Jim, I also eat only my home raised hormone free beef. I've only been raising cattle for 40 years so I'm kinda new at it! My thought is- Why take the risk? I'm so old I remember when "proven safe" drugs like Thalidimde and DES were routinely prescribed to women. 25 years later tragic problems of cancer came up with daughters of those women taking DES and birth defects were noted in children from users of Thalidimide. It took years for the full effect of DDT to show in our ecosystem. So why routinely use drugs and chemical agents when we really don't know the long term effects?

September, 17, 2012 at 02:02 PM

This question likely reveals my ignorance of hormones, but if the types of hormones administered to cattle do not include estrogen, why do the referenced measurements only refer to estrogen? That looks like a big oversight to me and it is not brought up in, let alone explained in the article. If this article is intended to explain the facts of hormone use to the general public—I know it's not given the publication and the author, though one can assume that might have been a goal of the author given the opening lines—wouldn't that apparent disconnect be a relevant thing to address, even if briefly?

SD  |  September, 20, 2012 at 10:58 PM

The information could be more clear as to which of the hormones are more frequently used, and which are more effective and specifically what effect each has in beef cattle. One reason for implanting has been to produce more lean muscle mass and less fat, which is exactly the type of beef many medical and nutrition professionals have been telling us we we produce what is asked for......and now are being criticized for doing so! It might be helpful if information re. affect of consuming hormones from different sources, since there is so much more hormone in some vegetables than in meats.

Arkansas  |  September, 26, 2012 at 10:44 AM

I think the point of the article was to shed some light on an often misunderstood subject by providing a brief overview. The point was not, in my opinion, to conduct and produce an extensive literature review. If that's what you're looking for, I recommend Hudson Institute's "The Environmental Safety and Benefits of Growth Enhancing Pharmaceutical Technologies in Beef Production" here: where you'll find specifics like acceptable daily intake of hormones (you get 1.43% of acceptable daily estrogen from a one pound hamburger). For some, like Jim, the science found in this article will never be considered. Their minds are already made up and can't be swayed by silly things like facts.

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