rBGH in Milk: What the Fox Reporters’ Story, Regulators, and Research Show About Bovine Growth Hormone

In the late 1990s, two investigative reporters at a Fox-owned television station in Tampa, Florida, prepared a series on recombinant bovine growth hormone, a genetically engineered hormone injected into dairy cows to increase milk production. The series was never aired as they wrote it, and the reporters were later fired. Their whistleblower lawsuit, and the story they set out to tell, became a symbol of concerns about corporate influence over media and about a product many consumers had never heard of.

The hormone, known as rBGH or rbST and sold under the brand name Posilac, remains approved in the United States but is not permitted in Canada, the European Union, and several other countries. Its use has declined sharply as retailers and dairy processors responded to consumer demand for milk from untreated cows. This article explains what rBGH is, what regulators concluded about human safety, what research shows about animal health and IGF-1, what happened in the Fox case, and how to read “rBST-free” labels.

Is rBGH in milk dangerous, and is it still used? rBGH (also called rBST) is a synthetic hormone once widely used to boost cows’ milk production. Regulators concluded milk from treated cows is safe for humans, since bovine growth hormone does not act in the human body. Concerns focus on elevated IGF-1 and effects on cows’ health. Its use has declined sharply in the U.S. as retailers and consumers rejected it, and many dairies are now rBGH-free.

What Is rBGH and How Does It Work?

rBGH (recombinant bovine growth hormone), also called rBST, is a genetically engineered version of a natural cow hormone, injected into dairy cows to increase milk production by about 10 to 15 percent. Cows naturally produce bovine growth hormone, also called bovine somatotropin, which helps regulate milk production. In the 1980s, companies including Monsanto developed a recombinant version, made by genetically engineered bacteria, that could be injected into dairy cows to increase milk yield, typically by around 10 percent or more. According to the FDA, it approved a bST product with the brand name Posilac in 1993 after determining that its use would be safe and effective; it is approved for use in dairy cows beginning a couple of months after calving through the end of lactation. Monsanto sold Posilac to Eli Lilly’s animal health division, Elanco, in 2008.

Is Milk From rBGH-Treated Cows Safe to Drink?

Regulators including the FDA concluded that milk from rBGH-treated cows is safe for humans to drink, because bovine growth hormone is not biologically active in the human body and is largely broken down in digestion. The FDA’s safety assessment focused on two questions: whether bovine growth hormone in milk could affect people, and whether changes in milk composition, particularly IGF-1, posed risks. A 1990 review in Science by FDA scientists Judith Juskevich and Greg Guyer summarized the evidence: bovine growth hormone is not biologically active in humans, rbGH was not orally active in rat toxicity studies, and although treatment increases IGF-1 concentrations in cow’s milk, bovine IGF-1 lacked oral activity in rats and levels remained within the normal range found in milk. The FDA concluded milk from treated cows was safe for human consumption. International expert bodies, including the Joint FAO/WHO Expert Committee on Food Additives, reached similar conclusions about human food safety.

Does rBGH Milk Raise Cancer Risk Through IGF-1?

The main scientific concern is that rBGH can raise levels of IGF-1, a growth factor, in milk; high IGF-1 has been studied in relation to cancer, but evidence that rBGH milk meaningfully raises human risk is inconclusive. The main human health concern raised by critics involves IGF-1, a hormone that promotes cell growth. Some observational studies have linked higher blood levels of IGF-1 to modestly higher risks of certain cancers, such as prostate, breast, and colorectal cancer. Because milk from rBGH-treated cows contains somewhat more IGF-1, critics argued that drinking it could raise cancer risk. The American Cancer Society’s review notes that while there may be a link between IGF-1 blood levels and cancer, the exact nature of that link remains unclear, and that it is not clear that drinking milk from rBGH-treated cows increases blood IGF-1 to a range that might increase cancer risk. The ACS also notes that the hormone is not permitted in the European Union, Canada, and some other countries.

Context matters: the human body produces large amounts of IGF-1 itself, and milk from any cow, treated or not, contains IGF-1. Drinking milk in general is associated with modestly higher blood IGF-1 levels in some studies, regardless of rBGH use. Whether the additional IGF-1 from treated cows makes a meaningful difference has not been established.

How Does rBGH Affect the Cows?

rBGH can increase health problems in cows, including mastitis (udder infection), lameness, and reproductive issues, which is a major reason it was banned in the EU, Canada, and other countries on animal-welfare grounds. Canada’s decision not to approve rBST in 1999 rested mainly on animal welfare. A meta-analysis published in the Canadian Journal of Veterinary Research in 2003 by Ian Dohoo and colleagues, based on work for Health Canada, found that rBST increased the risk of clinical mastitis by about 25 percent during treatment, increased the risk of a cow failing to conceive by about 40 percent, and raised the risk of lameness by about 55 percent. Mastitis, an udder infection, is often treated with antibiotics, so higher mastitis rates also raised concerns about antibiotic use in dairy herds. The European Union cited animal welfare in maintaining its ban.

The Fox Reporters’ Story

According to court records and public accounts of the case, in 1997 reporters Jane Akre and Steve Wilson at WTVT, a Fox-owned station in Tampa, began work on a series about Monsanto and rBGH. Monsanto’s lawyers sent letters to Fox raising concerns about the reports, and the station requested numerous revisions. The reporters said they were pressured to include statements they believed were false and refused; they were eventually fired. They sued under Florida’s whistleblower law. In 2000, a jury rejected Wilson’s claims but found for Akre, awarding her $425,000, concluding she had been fired for threatening to report the station to the Federal Communications Commission over what she considered news distortion. In February 2003, Florida’s Second District Court of Appeal reversed the verdict, ruling that the FCC’s news distortion policy was not a law, rule, or regulation covered by the whistleblower statute. The case was featured in the 2003 documentary The Corporation.

The case is often described as showing that it is legal for news outlets to distort the news. More precisely, the appeals court held that the FCC policy against news distortion did not qualify for protection under Florida’s whistleblower law, so the reporters’ firing was not illegal under that statute; it did not rule on whether the station’s requested edits were accurate.

Is Milk From Treated Cows Different From Regular Milk?

Milk from treated and untreated cows is nearly identical in composition; there is no reliable test to distinguish them, though treated-cow milk may have slightly higher IGF-1, and “rBGH-free” labels note production methods, not measurable differences. Studies comparing retail milk have found that differences between milk from treated and untreated cows are small. A 2008 survey in the Journal of the American Dietetic Association by John Vicini and colleagues, whose lead author worked for Monsanto, sampled conventional, rbST-free, and organic milk from across the United States and reported only minor differences in composition, including hormones such as somatotropin and IGF-1, among the three label categories. Because the study was conducted by researchers affiliated with the company that developed rBST, critics questioned its independence, but its findings are broadly consistent with regulators’ conclusions that composition differences are small. The FDA’s own review found IGF-1 in milk from treated cows within the normal range for cow’s milk, though somewhat higher on average.

Why Bovine Growth Hormone Does Not Act in Humans

Growth hormones are species-specific proteins. Human growth hormone receptors do not respond to bovine growth hormone, which is why bovine growth hormone was abandoned decades ago as a treatment for children with growth hormone deficiency. In addition, as a protein, bovine somatotropin is largely broken down by digestion into amino acids and peptides. IGF-1 is more similar between cows and humans, which is why the debate focused on IGF-1 rather than the growth hormone itself. Whether some IGF-1 from milk survives digestion and is absorbed in amounts that matter remains debated, though research suggests the body’s own production far exceeds what milk could contribute.

The Market Turned Away From rBST

Although rBST remained legal, consumer concern led many retailers, dairies, and restaurant chains to stop selling milk from treated cows in the late 2000s. Major grocery chains, coffee chains, and dairy cooperatives announced rBST-free policies, and many dairy processors now require suppliers to certify that cows are not treated. As a result, use of rBST in the U.S. dairy herd declined substantially from its peak. Organic milk has never been allowed to come from rBST-treated cows, since organic standards prohibit synthetic growth hormones.

Labeling Battles

As dairies began labeling milk “rBST-free” or “from cows not treated with rBST,” producers of the hormone and some dairy groups objected that such labels implied milk from treated cows was less safe. The FDA issued guidance in 1994 allowing voluntary labels if they are truthful and not misleading, recommending that they include context such as a statement that no significant difference has been shown between milk from treated and untreated cows. Some states tried to restrict rBST-free labels; Ohio’s restrictions were partly struck down by a federal appeals court in 2010, which found that milk from treated cows differs in composition, including higher IGF-1 levels, and that a blanket ban on such labels violated free speech protections. Today, many milk cartons carry rBST-free claims, often with the FDA-recommended qualifying statement.

Label	What it means
“From cows not treated with rBST”	Producer states cows were not given the hormone; often includes FDA-recommended context statement
USDA Organic	Synthetic hormones, including rBST, are prohibited
“Hormone-free”	Misleading: all milk naturally contains hormones
No claim	Milk may or may not come from treated cows; many processors now require untreated cows anyway

Organic and Grass-Fed Milk

Organic dairy standards prohibit synthetic hormones, including rBST, and require organic feed and pasture access during the grazing season. Some shoppers choose organic or grass-fed milk for these reasons, for animal welfare, or because of taste. Studies comparing organic and conventional milk have found differences in fatty acid profiles, such as more omega-3 fatty acids in milk from pasture-fed cows, but differences in overall nutrition are modest. Choosing milk from untreated cows does not require buying organic, since many conventional brands now certify that their milk comes from cows not treated with rBST.

Animal Welfare Considerations

For many people concerned about rBST, the strongest argument is not human health but animal welfare. Higher rates of mastitis, lameness, and fertility problems mean more pain, more treatment, and earlier culling for treated cows. Some farmers who used rBST argued that careful herd management could limit these problems and that the increased milk production per cow reduced resource use. Others stopped using it because of market demand and herd health concerns. The debate illustrates how agricultural technologies can affect animals, farmers, and consumers in different ways.

Common Myths

“rBGH milk causes early puberty.” There is no reliable evidence linking milk from treated cows to early puberty in children.

“rBGH is banned in the U.S.” It remains FDA-approved, though its use has declined.

“Organic milk has no hormones.” All milk naturally contains hormones; organic milk comes from cows not given synthetic hormones.

“Fox was found to have lied in court.” The appeals court ruled on whistleblower law coverage, not on the accuracy of the reporters’ claims or the station’s edits.

How Regulators in Other Countries Decided

Canada’s decision in 1999 followed reviews by expert panels of the Canadian Veterinary Medical Association and the Royal College of Physicians and Surgeons of Canada. The physicians’ panel found no significant human safety concerns, while the veterinary panel identified animal health risks, and Health Canada declined approval on animal welfare grounds. The European Union imposed a moratorium on rBST that became a permanent ban in 2000, citing animal welfare. Australia, New Zealand, Japan, and others have not approved it for use. At the international level, the Codex Alimentarius Commission did not adopt maximum residue limits for rBST because of disagreements among member countries, reflecting divisions over trade, animal welfare, and precaution.

Trade Implications

Because many countries do not permit rBST use, U.S. dairy exporters have faced questions from buyers about whether products come from treated cows. Some processors require certification of untreated milk partly to satisfy export customers. Trade negotiations have occasionally touched on hormone use in dairy and beef, as with the long-running dispute between the United States and the European Union over hormone-treated beef, which led to World Trade Organization rulings and retaliatory tariffs. These trade dimensions add economic incentives to the consumer-driven shift away from rBST.

Key Facts at a Glance

The FDA approved rBST (Posilac) in 1993, concluding milk from treated cows is safe; FDA scientists reported in 1990 that bovine growth hormone is not active in humans and that bovine IGF-1 lacked oral activity in rats. A 2003 meta-analysis for Health Canada found rBST increased clinical mastitis by about 25 percent, failure to conceive by about 40 percent, and lameness by about 55 percent; Canada rejected rBST in 1999 and the EU banned it. Reporter Jane Akre won a $425,000 verdict against WTVT in 2000, reversed on appeal in 2003. Many U.S. retailers and processors now sell milk only from untreated cows.

Further Reading

The FDA’s page on bovine somatotropin describes its approval and safety evaluation. The American Cancer Society summarizes evidence on rBGH and cancer. Health Canada’s decision documents and the Canadian Veterinary Medical Association panel report explain Canada’s reasoning. The 2003 Florida appeals court opinion explains the legal basis for reversing the whistleblower verdict.

Media, Corporations, and the Akre Case

The Akre and Wilson case has been widely cited in discussions of media independence. Supporters of the reporters argue it showed how advertisers and corporations can pressure news organizations, and how weak legal protections leave journalists vulnerable. Defenders of the station argued that editors have the right and responsibility to review stories for accuracy and legal risk, particularly when a company threatens litigation, and that disagreements over edits are part of normal journalism. The appeals court did not resolve those questions; it ruled that the reporters’ complaint did not fall under the whistleblower law. The case remains a useful example for journalism students studying the relationship between editorial independence, legal risk, and corporate pressure.

Questions Shoppers Ask

Is it worth paying more for rBST-free milk? Many conventional brands are already rBST-free at no premium, so checking labels may reveal you already buy untreated milk. Does rBST affect milk taste? Studies have not found consistent taste differences. Is chocolate milk or cheese affected? Dairy products made from milk of treated cows may carry no label, but many processors source untreated milk for all products. What about infant formula? Most infant formulas are made from processed milk proteins; manufacturers can provide information on sourcing.

The Science of IGF-1 and Cancer

IGF-1 promotes cell growth and division and inhibits programmed cell death, properties that could, in theory, support tumor growth. Large pooled analyses of observational studies have linked higher circulating IGF-1 levels to modestly higher risk of some cancers, particularly prostate and breast cancer. Blood IGF-1 levels are influenced by genetics, overall nutrition, protein intake, and body weight. Milk consumption in general is associated with slightly higher IGF-1 levels in some studies, but this association applies to milk from untreated cows as well. Whether the incremental IGF-1 from rBST-treated milk affects blood levels or cancer risk in any measurable way has not been demonstrated, which is why major cancer organizations describe the question as unresolved rather than settled in either direction.

Key Terms

rBGH / rbST: Recombinant bovine growth hormone, also called recombinant bovine somatotropin, a genetically engineered hormone used to increase milk production.

IGF-1: Insulin-like growth factor 1, a hormone involved in growth that occurs naturally in milk and in the human body.

Mastitis: Inflammation of the udder, usually from infection, often treated with antibiotics.

Posilac: The brand name of the rbST product approved by the FDA in 1993.

Whistleblower law: A law protecting employees from retaliation for reporting violations of laws, rules, or regulations.

The Bottom Line

Recombinant bovine growth hormone increases milk production and remains FDA-approved, with regulators concluding that milk from treated cows is safe for people, since bovine growth hormone is not active in humans and differences in milk composition, including IGF-1, are small. Canada and the European Union rejected rBST mainly because of animal health concerns, including higher rates of mastitis, lameness, and fertility problems. The Fox reporters’ case drew attention to the issue and to questions about media and corporate pressure, though the appeals court ruled on narrow legal grounds. Consumer demand has made milk from untreated cows the norm in many U.S. stores, and organic milk always comes from untreated cows.

The Dairy Industry Today

The U.S. dairy industry has consolidated substantially, with fewer and larger farms producing more milk per cow through genetics, nutrition, and management improvements rather than rBST. Dairy processors and cooperatives that buy milk from many farms often set standards for practices such as rBST use, animal welfare, and antibiotic residues. Consumer preferences, retailer requirements, and export markets now shape practices as much as regulations do. This shift illustrates how market forces can change agricultural practices even when a product remains legal.

Further Context

The rBGH story is often discussed alongside other agricultural technologies, such as genetically engineered crops and growth-promoting hormones in beef cattle. In each case, debates involve human safety, animal welfare, environmental effects, trade, corporate power, and consumer choice. Regulators in different countries weigh these factors differently, and consumers increasingly influence outcomes through purchasing decisions and support for labeling.

How rBST Increases Milk Production

Bovine somatotropin works by redirecting nutrients toward milk production. It increases the number and activity of milk-secreting cells in the udder and prompts the cow’s body to mobilize energy from fat reserves and feed for milk synthesis, partly by raising IGF-1 levels in the cow. Treated cows typically eat more to support higher production, and their management must account for greater nutritional demands. When nutrition and management are inadequate, the additional metabolic stress may contribute to health problems such as mastitis and lameness. This physiology helps explain both the productivity benefits farmers sought and the animal health concerns that regulators in other countries emphasized.

Economics of rBST

When rBST was introduced, supporters argued it would lower the cost of producing milk and allow farmers to produce more with fewer cows. Critics warned it would increase milk surpluses, drive down prices, and favor larger farms that could manage its demands. In practice, adoption peaked in the late 1990s and early 2000s, then declined as retailers responded to consumer preferences. For many farmers, the price premiums or market access associated with rBST-free milk outweighed the production gains, and processors’ requirements made the decision for many others.

What Changed and What Did Not

Three decades after approval, the scientific conclusions on rBST have changed little: regulators still consider milk from treated cows safe for people, and animal health effects remain the main concern. What changed was the market. Consumer awareness, driven in part by stories like the Fox reporters’ case and by labeling, led retailers and processors to move away from rBST. The story shows how public concern, even when it outpaces evidence of human harm, can reshape agricultural practices, and how animal welfare can become a decisive factor in food policy.

Questions to Ask Your Dairy

If you buy milk from a local dairy or farmers market, you can ask directly: Are your cows ever treated with rBST? How are cows fed and housed? Do you use antibiotics, and how are treated cows’ milk withheld? Small dairies often welcome these questions and can explain their practices in detail. For store brands, company websites and customer service lines can confirm sourcing policies, including whether all products or only certain lines come from untreated cows.

Many processors now include rBST policies in their published sustainability or animal welfare reports.

Antibiotics and Milk Safety

Because rBST can increase mastitis, a related concern is antibiotic use. Federal rules require that milk from cows treated with antibiotics be withheld from the food supply for a specified period, and every tanker load of milk is tested for antibiotic residues before processing; loads that test positive are discarded. These safeguards apply to all dairy farms regardless of rBST use. The broader concern is that increased antibiotic use on farms can contribute to antibiotic resistance, a public health issue that has led to stricter rules on antibiotic use in food animals.

Lessons for Consumers

The rBGH story offers several lessons. Regulatory approval addresses specific safety questions but may not resolve every concern, such as animal welfare. Labels can empower choice when they are truthful and provide context. Market forces can change practices even when products remain legal. And understanding the evidence, rather than relying on alarming headlines, helps people make decisions aligned with their values, whether those prioritize animal welfare, cost, or other factors.

For readers interested in the policy dimension, the rBGH debate also shows how differing regulatory standards across countries can coexist, with each system reflecting its own balance of scientific evidence, animal welfare priorities, consumer preferences, and trade considerations rather than a single universally accepted answer.

Readers who want to dig deeper can compare the FDA’s approval documents with Health Canada’s decision summary and the European Commission’s reports on bovine somatotropin, which lay out how each regulator weighed the same body of evidence on human safety and animal health before reaching different conclusions, offering a useful case study in how scientific evidence and policy values interact across different regulatory systems.

Frequently Asked Questions

Is rBGH still used in the United States?

rBGH use in the United States has declined sharply since its 1990s peak, though it is still legal. After consumer concern and retailer pressure, many major dairies, grocery chains, and brands went rBGH-free, and much of the U.S. milk supply now comes from untreated cows. It remains permitted by the FDA, but market forces, not a ban, have greatly reduced its use. It is banned outright in the EU, Canada, and other countries.

Is milk from rBGH-treated cows safe to drink?

According to the FDA and other regulators, yes. Milk from cows treated with rBGH is considered safe for humans because bovine growth hormone is not biologically active in people and is broken down during digestion like other proteins. The scientific consensus is that there is no meaningful health difference for consumers between milk from treated and untreated cows, though some concerns about IGF-1 remain debated.

What is the concern about IGF-1 in rBGH milk?

rBGH can slightly raise levels of insulin-like growth factor 1 (IGF-1) in milk. Because high IGF-1 levels in the body have been studied in relation to some cancers, critics worry about this effect. However, IGF-1 is also present in untreated milk and the human body, much is broken down in digestion, and evidence that the small increase from rBGH milk meaningfully raises human cancer risk is inconclusive.

Why is rBGH banned in other countries?

The European Union, Canada, Japan, Australia, and others banned rBGH largely on animal-welfare grounds rather than human food-safety concerns. Studies showed rBGH increases health problems in cows, including mastitis (a painful udder infection often requiring antibiotics), lameness, and reproductive issues. These countries concluded the animal-health risks were unacceptable, which is a key difference from the U.S. regulatory approach.

How can I avoid rBGH milk?

Avoiding rBGH milk is easy in the United States today. Look for milk and dairy products labeled “rBGH-free,” “rBST-free,” or “produced without artificial growth hormones,” which many brands now carry. Certified organic milk also prohibits rBGH, so choosing organic dairy avoids it as well. Because so much of the market has shifted away from rBGH, these options are widely available in most grocery stores.

References

1. Juskevich JC, Guyer CG. Bovine growth hormone: human food safety evaluation. Science. 1990;249(4971):875–884. PMID 2203142
2. Dohoo IR, DesCôteaux L, Leslie K, et al. A meta-analysis review of the effects of recombinant bovine somatotropin. 2. Effects on animal health, reproductive performance, and culling. Canadian Journal of Veterinary Research. 2003;67(4):252–264. PMID 14620861
3. U.S. Food and Drug Administration. Bovine Somatotropin (bST). fda.gov
4. American Cancer Society. Recombinant Bovine Growth Hormone. cancer.org
5. New World Communications of Tampa, Inc. v. Akre, Florida Second District Court of Appeal, February 14, 2003. courtlistener.com
6. Vicini J, Etherton T, Kris-Etherton P, et al. Survey of retail milk composition as affected by label claims regarding farm-management practices. Journal of the American Dietetic Association. 2008;108(7):1198–1203. PMID 18589029

Last updated: October 6, 2026