Every piece of meat contains hormones, because animals make them naturally, just as people do. In the US, added growth hormones are used in only one common meat, beef, and the extra amount they leave behind is very small next to what your own body produces. So the real scientific question is not whether hormones are present but whether such small extra amounts matter over a lifetime, and that part is not fully settled.
How Much Extra Hormone Is Really In Treated Beef
A 3-ounce serving of beef from an untreated steer has about 1.3 nanograms of estrogen, a billionth of a gram each.1Farm Progress. Beef implants: Common questions answered The same serving from a steer given a growth implant has about 1.9 nanograms.2Farm Progress. Beef implants: Common questions answered An extension service that measured overall estrogen-like activity found a similar gap, 0.85 versus 1.2 units per serving.3SDSU Extension. Hormones in Beef: Myths vs. Facts Treated beef, then, carries roughly half again as much estrogen as untreated beef, but both amounts are tiny. The gap works out to about 0.6 nanograms per serving, nothing like a hormone-containing medication, which delivers doses thousands of times larger.
The two measurements use different units because the first counts actual estrogen in the meat, while the extension service figure estimates overall estrogen-like activity. Compare treated with untreated within each measure, not across them. Eggs, milk and soy-based foods also carry hormones or hormone-like compounds naturally, and the gap between treated and untreated beef is smaller than the natural difference between some of those foods.
No beef is truly hormone-free, since every cow makes estrogen and testosterone on its own. Labels such as “no added hormones” or “raised without hormones” mean only that no implants were used. Even a large 500-gram portion of treated meat supplies estradiol, the main estrogen, at levels about 40 to thousands of times lower than what a person produces daily.4PubMed Central. Risk Assessment of Growth Hormones and Antimicrobial Residues in Meat Daily production varies by age, sex and time of month, which is why the range is so wide.
Which Meats Have Added Hormones
In the US, steroid growth implants are allowed only in beef cattle and sheep.5The Humane League. Do Growth Hormones in Chickens Affect Humans & Increase HGH? A growth implant is a small pellet placed under the skin of the ear. It makes animals grow faster and turn feed into meat more efficiently.6The Humane League. Do Growth Hormones in Chickens Affect Humans & Increase HGH? Approved implants use natural estrogen, progesterone and testosterone, or synthetic versions of them.7The Humane League. Do Growth Hormones in Chickens Affect Humans & Increase HGH?
The pellet releases hormone slowly over weeks. The ear is used because it is discarded at slaughter and never enters the food supply.
Other meats are off the list. No steroid hormones are approved for growth in poultry, pigs, veal calves or dairy cattle.8Mississippi State University Extension Service. Chickens Do Not Receive Growth Hormones: So Why All the Confusion? Chickens’ fast growth and large breasts come from breeding and feed, not hormones. That means a “no hormones added” label on chicken or pork describes every package of that meat sold in the US, so paying more for it buys nothing extra on this point.
For beef, look for “no added hormones” or organic if you want to avoid implants. Imported meat follows the rules of its home country, so practices can differ.
Milk is a slightly different story. Milk from cows given a protein growth hormone called rbST showed no meaningful change in hormone levels in international expert reviews.9PubMed Central. The Promise and Challenges of Determining Recombinant Bovine Growth Hormone in Milk rbST is given to some dairy cows to increase milk output, and it is a different kind of substance from the steroid hormones in beef implants. Milk always carries natural hormones from the cow, so a “no added hormones” label doesn’t mean the milk contains none. A label saying the cows weren’t treated with rbST speaks to rbST specifically, not to steroid implants, which dairy cows don’t receive.
What Happens To Hormones After You Eat Them
Steroid hormones like estrogen are not proteins, so unlike many hormones they can pass through the gut into the body.10Best Food Facts. Are There Hormones in My Food? Part 1 But the liver intercepts and breaks down or removes hormones from both animal and plant foods.11Best Food Facts. Are There Hormones in My Food? Part 1 Much of the small amount you swallow is cleared before it can act.
Protein hormones, such as the growth hormone used in dairy, are chains of amino acids. Stomach acid and digestive enzymes cut them into pieces that the body treats as ordinary food protein. Steroid hormones are small, fat-soluble molecules that can slip through the gut wall without being broken apart first.
Blood leaving the intestines travels through the liver before it reaches the rest of the body, and the liver can chemically modify steroids so they leave in bile and urine. This is why a hormone swallowed in food generally has much less effect than the same amount injected, which skips that first pass.
Gut bacteria add a twist. Some make enzymes that can reactivate estrogen the liver has tagged for removal, sending it back into the blood.12PubMed. From Gut to Hormones: Unraveling the Role of Gut Microbiota in (Phyto)Estrogen Modulation in Health and Disease How much estrogen circulates therefore depends partly on your own gut bacteria.13PubMed Central. Relationship between gut microbiota and host-metabolism: Emphasis on hormones related to reproductive function This affects the estrogen your body makes too, so it isn’t specific to meat.
Are Residues Kept Within Safe Limits
Each hormone drug has a maximum residue limit, the most allowed to remain in meat.14PubMed Central. Anabolic Steroids in Fattening Food-Producing Animals—A Review Testing of US beef found the synthetic steroid trenbolone and estradiol within those limits.15PubMed. Surveillance of Anabolic Agent Residues in US Meat Supply by Liquid Chromatography With High-Resolution Tandem Mass Spectrometry But beef from some exporting countries, including the US, has tested above limits for trenbolone even when labeled hormone-free.16PubMed Central. Anabolic Steroids in Fattening Food-Producing Animals—A Review A legal limit is set well below the level at which any effect was seen, so meat above it is not automatically harmful but is treated as a violation. The trenbolone result points to a lapse in compliance, not proof of harm.
Experts disagree on policy. The international food-standards body judged meat from properly treated cattle safe.17Nutrition Research Reviews. Hormones in international meat production: biological, sociological and consumer issues The European Union nonetheless bans hormone-treated beef on a precautionary basis.18Nutrition Research Reviews. Hormones in international meat production: biological, sociological and consumer issues The US asks whether harm has been shown, while the EU asks whether safety is certain.
History explains some of the caution. One past hormone, DES, is now banned in all food animals because of its cancer and birth-defect risks.19PubMed. Diethylstilboestrol–historical background and current regulatory status It was once widely used and later linked to cancers in people exposed. That experience is why regulators now test hormones before approval, and today’s implants are different compounds with set limits.
Meat And Early Puberty In Children
In a study of Chinese girls, those eating the most red meat had nearly three times the odds of very early puberty.20PubMed Central. Dietary pattern and precocious puberty risk in Chinese girls: a case-control study In another, girls eating red meat twice a day or more had their first period earlier than those eating it fewer than four times a week.21PubMed. Higher Childhood Red Meat Intake Frequency Is Associated with Earlier Age at Menarche But these studies measured meat eaten, not hormone residues.22PubMed. Higher Childhood Red Meat Intake Frequency Is Associated with Earlier Age at Menarche Extra calories, body weight or protein could explain the link as well as hormones could. Studies like these are observational, so they can’t show that meat itself changed the timing of puberty.
Body weight is one of the strongest known factors in earlier puberty. Body fat produces its own estrogen and signals the brain about energy stores, which is one reason heavier girls tend to start earlier. Diets high in meat are often higher in calories overall, so the effect could run through weight gain and not through residues in the meat. Fruit and vegetables were linked to lower risk in the same research, and genetics and family history also shape timing. For parents, a varied diet with plenty of produce fits the findings either way.
Puberty that begins before age 8 in girls or 9 in boys is considered early and warrants a medical check, since doctors can look for underlying causes. Most children who start a little earlier than their friends are within the normal range and don’t need treatment.
Cancer And Fertility Questions
Scientists say it isn’t currently possible to measure breast cancer risk from meat hormones, because long-term feeding studies are missing.23PubMed. Hormone Use in Food Animal Production: Assessing Potential Dietary Exposures and Breast Cancer Risk One synthetic progestin fed to cattle, MGA, caused breast changes in animals only at high doses.24PubMed Central. Estimated human intake of endogenous and exogenous hormones from beef in the United States MGA is used in feed for heifers. High-dose animal results work as a warning flag for regulators, but they don’t translate directly into what happens at the tiny amounts left in beef. Whether those low amounts matter remains unknown.25PubMed Central. Estimated human intake of endogenous and exogenous hormones from beef in the United States
Red meat itself has better-established concerns. Processed and red meat are linked to colorectal cancer for reasons unrelated to implants, so cutting processed meat matters more than choosing hormone-free beef.
On fertility, men at a fertility clinic who ate the most processed meat had slightly fewer normally shaped sperm.26PubMed Central. Processed Meat Intake Is Unfavorably and Fish Intake Favorably Associated with Semen Quality Indicators among Men Attending a Fertility Clinic That links processed meat in general, not hormones, to sperm quality.
Some people may want to be more careful. Young children make very little of their own sex hormones, so small extras make up a larger share of what is in their bodies. People with hormone-sensitive cancers may prefer no-added-hormone beef for peace of mind. Personal concerns are better discussed with a doctor than handled by cutting out foods.
Does Cooking Remove Hormones
Estradiol holds up under boiling and frying temperatures.27PubMed. Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef Still, cooking ground beef lowers hormone levels, by 25 to 30 percent in regular ground beef and 5 to 20 percent in extra lean.28PubMed. Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef Some hormone leaves with the fat that cooks out.29PubMed. Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef Draining that fat removes a little more.
Most of the hormone is still there after cooking, so cooking is no way to make beef hormone-free. Regular ground beef loses more because it has more fat to cook out.
In the kitchen, pour off the fat after browning ground beef. Choosing leaner cuts also lowers saturated fat. Safety matters more than hormone reduction, though. Grinding mixes surface bacteria into the middle, so ground beef needs to reach 160°F. A food thermometer in the thickest part is the reliable check, since color alone can mislead, and draining fat doesn’t conflict with it.
Hormones From Farms In Water And Dust
Runoff from grazing land, and manure spread on frozen fields, can carry hormones, especially progesterone, into streams.30PubMed. Occurrence of estrogens, androgens and progestogens and estrogenic activity in surface water runoff from beef and dairy manure amended crop fields Levels can reach amounts known to affect fish.31PubMed. Occurrence of estrogens, androgens and progestogens and estrogenic activity in surface water runoff from beef and dairy manure amended crop fields Raw water and dust may carry these hormones to people too.32PubMed. The Fate of Synthetic and Endogenous Hormones Used in the US Beef and Dairy Industries and the Potential for Human Exposure So far the concern centers on fish and other wildlife, which are exposed continuously and are sensitive to small amounts.
Treated city water goes through processes that reduce many contaminants, while private wells near large livestock farms are worth testing. These hormones come from all cattle, treated or not, so choosing no-added-hormone beef doesn’t remove this source. The effect depends on how many animals are in an area and how manure is managed, which makes it a land-use question and not a labeling one.