Federal regulation of growth hormones in livestock runs through the FDA, which approves specific substances for specific species and nothing else. Steroid hormone implants are approved for beef cattle and sheep. A synthetic hormone in feed, melengestrol acetate, is approved for heifers. Beta-agonists (a non-hormone class of growth promoter) are approved for finishing swine and cattle. Recombinant bovine somatotropin is approved for dairy cows. No growth hormones are approved for poultry, pigs, dairy cows, or veal calves. The USDA’s Food Safety and Inspection Service tests meat at slaughter, and violations of residue limits or withdrawal periods carry both criminal and civil penalties.
What’s Approved for Beef Cattle and Sheep
Since the 1950s, the FDA has approved several steroid hormones to increase growth rates and feed efficiency in beef cattle and sheep. Three are naturally occurring hormones the animals already produce: estradiol, progesterone, and testosterone. Two are synthetic compounds designed to mimic natural hormone activity: trenbolone acetate and zeranol.
These drugs come as small pellets implanted under the skin on the back of the ear. The pellet dissolves gradually and releases the hormone over weeks or months. Because ears are discarded at slaughter, the delivery site never enters the food supply, which keeps residue in edible tissue to a minimum.
Melengestrol acetate works differently. It is mixed into feed for heifers and does two jobs at once: it increases weight gain and feed efficiency, and it suppresses the estrus cycle, which cuts down on the behavioral disruptions cycling animals cause in a feedlot.
Beta-Agonists for Swine and Cattle
Beta-agonists are a separate class of growth promoter. They are not hormones. They work by redirecting nutrients toward lean muscle rather than fat, and they are added to feed during the final weeks before slaughter.
Ractopamine hydrochloride is approved for both finishing swine and beef cattle fed in confinement. In swine it is used during the last 45 to 90 pounds of growth. In cattle it is used during the final 28 to 42 days on feed.
Zilpaterol hydrochloride was approved in 2006 for cattle in confinement during the last 20 to 40 days before slaughter, with a three-day withdrawal period. The manufacturer voluntarily suspended U.S. sales in 2013 after animal welfare concerns surfaced at feedlots. The FDA approval remains in place on paper, but zilpaterol is not commercially available in the United States.
rbST in Dairy Cows
Recombinant bovine somatotropin, known as rbST or rbGH, is an engineered version of a hormone dairy cows naturally produce. The FDA approved it in 1993 under the brand name Posilac. Producers inject the drug every 14 days starting about two months after calving, and it boosts milk output through the end of the lactation cycle. The withdrawal period is zero days, meaning milk and meat from treated cows are considered safe at any point after treatment.
The FDA has stated that no significant difference exists between milk from rbST-treated cows and milk from untreated cows. Producers can label milk as coming from untreated cows, but the FDA’s 1994 guidance recommends that such labels carry a clarifying statement (something like “No significant difference has been shown between milk derived from rbST-treated and non-rbST-treated cows”) so consumers do not read the label as a safety or nutrition claim.
Species Where No Growth Hormones Are Allowed
No steroid hormone implants are approved for growth promotion in poultry, swine, dairy cows, or veal calves. Every chicken, turkey, and duck sold in the United States has been raised without added steroid hormones because the FDA has never approved such drugs for those species. The same is true for pork with respect to hormones. Ractopamine, which is approved for finishing swine, is a beta-agonist, not a hormone.
This matters at the meat case. A “No Hormones Added” label on chicken or pork is technically accurate but can mislead a shopper who assumes the producer made a special effort. Federal labeling rules require any such claim on poultry or pork to be accompanied by a statement explaining that federal regulations already prohibit hormone use in that species.
How the FDA Approves These Drugs
The FDA’s Center for Veterinary Medicine is the gatekeeper for every growth-promoting substance used in food-producing animals. Under federal law, a new animal drug is considered unsafe until the FDA approves a formal application for its intended use. The manufacturer must submit full reports on safety and effectiveness, a description of chemical composition, manufacturing methods, proposed labeling, and testing methods capable of detecting residues the drug might leave in edible tissue.
The safety standard is “reasonable certainty of no harm.” That does not demand absolute proof of harmlessness. It requires enough scientific evidence to satisfy qualified experts that the drug will not harm the treated animal or the people who eat the resulting meat, milk, or eggs. Safety must be shown for both.
Once a drug is approved, the FDA sets tolerance levels: the maximum residue concentration allowed in edible tissue. These limits are calculated using the drug’s toxicology profile and assumptions about how much meat a person might eat daily over a lifetime. The zilpaterol approval, for example, set an acceptable daily intake of 0.083 micrograms per kilogram of body weight and a tolerance of 12 parts per billion in liver tissue.
Withdrawal Periods and Producer Responsibilities
Every approved growth-promoting drug carries a withdrawal period printed on its label. This is the minimum number of days between the last dose and the date the animal can be shipped to slaughter. During that window, the drug and its metabolites deplete from tissue to levels at or below the FDA’s safety thresholds. Zilpaterol required three days; other drugs may require longer.
Ignoring the withdrawal period is illegal. Under the Federal Food, Drug, and Cosmetic Act, using an approved animal drug contrary to its label directions violates federal law. If residues turn up in meat above permitted levels, the food is legally adulterated. Producers carry the primary duty to track treatment dates and hold animals long enough.
Records back this up. Producers using medicated feeds covered by the Veterinary Feed Directive must keep documentation for at least two years. The prescribing veterinarian and the feed distributor each keep their own copies. Feed distributors who manufacture VFD-regulated feeds must also keep separate manufacturing records for at least one year. All records must be available for FDA inspection on request.
Residue Testing at Slaughter
The USDA’s Food Safety and Inspection Service runs the National Residue Program, which monitors meat and poultry for chemical residues at every federally inspected slaughter facility. The FDA sets the thresholds and approves the drugs; FSIS collects and tests tissue samples at slaughter.
Testing works two ways. Scheduled surveillance sampling targets healthy animals at random to build a statistical picture of the national supply. Inspector-generated sampling targets animals showing signs of a potential residue problem, such as injection-site reactions or evidence of recent treatment. Laboratory methods include liquid chromatography and mass spectrometry, sensitive to parts-per-billion concentrations.
When a sample comes back above the legal tolerance, the response is immediate. The inspecting veterinarian condemns the violative tissue. If muscle tissue contains the violation, the whole carcass and all organs are condemned. If only organ tissue tests positive and the muscle is clean, the organs are condemned but the carcass may pass. The slaughter facility must reassess its food safety plan and document corrective actions.
Producers whose animals trigger more than one residue violation within a 12-month period land on the FSIS Residue Repeat Violator List. The list is public. FSIS may screen-test up to 100 percent of future shipments from listed producers, and slaughter facilities become reluctant to buy from them. A producer stays on the list until the pattern of violations stops.
Penalties
Penalties under the Federal Food, Drug, and Cosmetic Act depend on whether the violation is criminal or civil and on prior history. A first-time criminal violation carries up to one year in prison, a fine of up to $1,000, or both. With a prior conviction, or with intent to defraud, the ceiling rises to three years in prison and a $10,000 fine.
Civil penalties apply separately when adulterated food enters interstate commerce. An individual can face up to $50,000 per violation. A business or other entity can face up to $250,000. The total civil penalty in a single proceeding is capped at $500,000.
The Federal Meat Inspection Act adds another layer. Selling or transporting misbranded or adulterated meat in commerce is a federal offense carrying up to one year in prison and a $1,000 fine, rising to three years and $10,000 with intent to defraud. Beyond criminal prosecution, the FSIS Administrator can move to withdraw a facility’s grant of federal inspection. Without that grant, the facility cannot legally slaughter animals or sell meat products in the United States, which for most operations is a shutdown.
Export Rules That Shape What Producers Use
The substances approved in the United States are not universally accepted abroad, and the trade rules push some producers to skip approved drugs entirely.
The European Union has banned imports of meat from hormone-treated animals since the late 1980s. The United States challenged the ban at the World Trade Organization, which found it inconsistent with international trade obligations because it was not based on a proper scientific risk assessment. The EU kept the ban anyway. In 2019 the two sides reached a compromise: a duty-free tariff-rate quota for high-quality U.S. beef produced without growth hormones. The U.S. allocation started at 18,500 metric tonnes and rises annually over seven years to a permanent 35,000 metric tonnes. To qualify, U.S. producers must participate in the USDA’s Non-Hormone Treated Cattle Program, which requires third-party audits, segregation of treated and untreated animals through the supply chain, and tissue sampling at slaughter.
Beta-agonists face an even wider wall. Ractopamine is banned from food production in more than 160 countries, including the EU, China, and Russia. Russia has conditioned any lifting of its ban on U.S. meat on certification that the meat is ractopamine-free. The Codex Alimentarius Commission adopted maximum residue limits for ractopamine in 2012, but the standards remain disputed and many importing nations refuse to recognize them. Export-oriented U.S. operations often avoid beta-agonists entirely to keep foreign buyers.
Marketing Claims and the USDA Organic Seal
Meat labels claiming “No Hormones Added” or “Raised Without Hormones” fall under the USDA’s Agricultural Marketing Service. Producers who want to use these claims must submit documentation proving the animals were never treated with growth-promoting substances from birth through slaughter. Verification involves record-keeping and site audits, and label approval must be obtained before the claim reaches retail packaging.
On poultry or pork, the claim must include the qualifying statement explaining that federal regulations already prohibit hormone use in the species. Without that context, the label reads as a distinction that does not exist.
The USDA Organic seal is a broader guarantee. Meat carrying the seal must come from animals raised without growth hormones, synthetic promoters, or antibiotics used for growth promotion. The organic standard covers the animal’s entire life and is verified through an independent certification process.
Misbranding meat products carries consequences under the Federal Meat Inspection Act. If labeling is false or misleading, the USDA can direct the company to modify its packaging, order a product recall, or pursue criminal penalties. For most producers, the cost of a recall itself outweighs the fine.