On this page:
Hormones in Beef
Environmental Impact
Hormones in Milk and Dairy Products
Did You Know?
What You Can Do

In 2011, more than 34 million cattle and 850,000 calves were slaughtered to provide beef for US consumers.   1 An estimated 80 percent of all US feedlot cattle are injected with hormones to make them grow faster,   2 and one government study from 2007 estimated that approximately 17 percent of all cows in the US were given the genetically engineered growth hormone rBGH  to increase milk production.   4 This means higher profits for the beef and dairy industries - but at what cost? Although the USDA and FDA claim these hormones are safe, there is growing concern that hormone residues in meat and milk are harmful to human health, animal health, and the environment.

Hormones in Beef

According to the European Union’s Scientific Committee on Veterinary Measures Relating to Public Health (SCVPH), the use of six natural and artificial growth hormones in beef production pose a potential risk to human health.   5 These six hormones include three that are naturally occurring – Oestradiol, Progesterone and Testosterone – and three that are synthetic – Zeranol, Trenbolone, and Melengestrol. When hormones are injected into cattle, some naturally occurring hormone levels increase 7 to 20 times.   6  The committee found that “no acceptable daily intake could be established for any of these hormones.”   7  

The Committee also questioned whether hormone residues in the meat of growth enhanced animals can disrupt human hormone balance, causing developmental problems, interfering with the reproductive system, and even leading to the development of breast, prostate and colon cancers.   5

Children, pregnant women, and developing embryos are thought to be most susceptible to negative health effects from added hormones. For example, hormone residues in beef have been examined as a cause of lower sperm counts in boys.   8 The use of rBGH in dairy cows was linked in one study to increases in human twin and triplet births.   9

Environmental Impact

Growth-promoting hormones not only remain in the meat we consume, but also pass through the cattle to be excreted in manure. Scientists are increasingly concerned about the environmental impacts of this hormone residue as it leaks from manure into the environment, contaminating soil, and surface and groundwater.   9 Aquatic ecosystems are particularly vulnerable to hormone residues. Recent studies have demonstrated that exposure to hormones has a substantial effect on the gender and reproductive capacity of fish.   2

Despite international scientific concern, the United States, backed by the World Trade Organization,   10 continue to allow growth-promoting hormones in cattle.   11  The European Union does not allow the use of hormones in cattle production, has prohibited the import of hormone-treated beef since 1988, and has banned all imports of US beef treated with hormones.   12 The ban has been challenged by the US at the World Trade Organization and debate still rages between the US and the EU over its validity.   13  

Hormones in Milk and Dairy Products

Industrial farms  use a number of methods to increase milk production in dairy cows, including selective breeding, feeding grain-based diets (instead of grass), and exposing cows to longer periods of artificial light. One of the most common and controversial ways to force greater milk production is with injection of rBGH (recombinant bovine growth hormone), a genetically engineered artificial growth hormone.

Developed and manufactured under the brand name Posilac® by the Monsanto Corporation, rBGH was approved by the FDA in 1993, despite strong opposition from scientists, farmers, and consumers.  In August 2008, Monsanto sold their Posilac division to Eli Lilly and Company for $300 million.

According to critics, rBGH has never been properly tested. The FDA relied solely on one study performed by Monsanto in which rBGH was tested for 90 days on 30 rats. The study was never published, and the FDA stated that the results showed no significant problems. A review of rBGH by Health Canada found the 90-day study showed a significant number of issues that should have triggered a full review by the FDA.   15

Visit our rBGH page to read more about the approval the hormone and its effects on human and animal health.

Did You Know?

• According to Science News, 80 percent of all US feedlot cattle are injected with hormones.   2  
• A study of cows treated with melengestrol acetate (one of the artificial growth hormones approved for use in the US) revealed that residues of this hormone were traceable in soil up to 195 days after being administered to the animals.   16  
• While the average dairy cow produced almost 5,300 pounds of milk a year in 1950,   17  today, the average is more than 20,000 pounds.   18

What You Can Do

• Many independent ranchers and farmers don’t use artificial hormones on their animals. By purchasing your milk and meat from local, sustainable farms, you are supporting a system that ensures the health and welfare of the farm animals, and protects you and your family from hormone-related health risks.
• Choose hormone-free beef and rBGH-free dairy products at the supermarket. Foods that carry the “USDA-certified organic”  label cannot come from animals given any artificial hormones. When purchasing sustainably raised foods without the "organic" label, be sure to check with the farmer to ensure no hormones were administered.


  • Organic
  • US Department of Agriculture, National Agriculture Statistics Service. (2012, July 19). 2012 milk production.
  • Hallberg, M. C. (2003). Historical perspective on adjustment in the food and agriculture sector. Penn State University. Retrieved Nov. 21, 2012.
  • Daxenberger, A., Meyer, H., Meyer, K., & Schiffer, B. (2011). The fate of trenbolone acetate and melengestrol acetate after application as growth promoters in cattle: Environmental studies. Environmental Health Perspectives, 109(11). Retrieved Nov. 21, 2012.
  • Hansen, M. (1998, December 15). FDA's safety assessment of recombinant bovine growth hormone. Consumer Union . Retrieved August 16, 2012.
  • Factory Farm (Industrial Farm / Industrial Agriculture)
  • World Trade Organization. (2010). United States — continued suspension of obligations in the EC — hormones dispute. Dispute DS320 Settlement Summary . Retrieved Nov. 21, 2012.
  • Laurence, Peter. (2012, March 14). Trade deal eases EU-US beef war over hormones. BBC News Europe.
  • Food and Drug Administration Center for Veterinary Medicine. (2002). The use of steroid hormones for growth promotion in food-producing animals. FDA Veterinarian Newsletter, 2002, XVI (V). Retrieved Nov. 21, 2012.
  • Federation of American Scientists. (1999). The US-EU hormone dispute. Retrieved Nov. 21, 2012.
  • Steinman, G. (2007). Twinning and higher intake of dairy products. Journal of Reproductive Medicine.
  • University of Rochester Medical Center. (2007). Maternal beef diet could impact sperm counts, UR study suggests. Retrieved Nov. 21, 2012.
  • European Commission Food Safety. (2007). Hormones in meat - introduction. Food and Feed Safety. Retrieved Nov. 21. 2012.
  • The Scientific Committee on Veterinary Measures Relating to Public Health. (2002). Opinion of the scientific committee on veterinary measures relating to public health on review of previous scvph opinions of 30 April 1999 and 3 May 2000 on the potential risks to human health from hormone residues in bovine meat and meat products. European Commission. Retrieved Nov. 21, 2012.
  • European commission, Scientific Committee on Veterinary Measures Relating to Public Health. (1999). Assessment of potential risks to human health from hormone residues in bovine meat and meat products. Retrieved Nov. 21, 2012.
  • USDA, Veterinary Services, Animal and Plant Health Inspection Service. (2007). Dairy 2007 part i: Reference of dairy cattle health and management practices in the United States, 2007.
  • rBGH
  • Raloff, J. (2002). Hormones: Here's the beef - Environmental concerns reemerge over steroids given to livestock. Science News, 161(1). Retrieved Nov. 21, 2012.
  • United States Department of Agriculture, National Agriculture Statistics Service. (2012). Livestock slaughter annual summary. Retrieved Nov 21, 2012.