Olympic Doping Controversy Exposes Hidden Hormone Misuse in Livestock Farming

Whether these rulings reflect the full truth or serve as convenient excuses is impossible for ordinary people to verify. But over the years, the World Anti-Doping Agency (hereafter WADA) has identified thousands of similar cases, demonstrating that doping-induced meat contamination is widespread across the world, including in China.

Why do meat products contain doping substances? Can ordinary people, just as easily as athletes, end up eating meat laced with banned substances?

Following several doping substances at the centre of this controversy, and after a thorough review of various investigation reports, media coverage and dozens of academic studies, we uncovered overlooked food safety risks in China’s livestock industry. The issues exposed either diverge significantly from the official line of government food safety authorities, or fall outside the scope of government oversight or public disclosure.

Key findings include:

• Clenbuterol, known colloquially as “lean-meat powder”, has long been banned, is included in routine market testing, and is subject to strict enforcement by regulators—yet illegal use persists despite repeated bans.

• Growth-promoting hormones such as trenbolone are used illegally in livestock fattening, with significant regulatory blind spots;

• Metandienone is a hormone for human use, yet anti-doping tests have detected it in meat.

I. Clenbuterol: Twenty Years of Failed Bans

The more accurate term for “doping agents” is “performance-enhancing drugs” (PEDs), which encompasses both short-acting substances that heighten an athlete’s acute alertness and competitive performance, and long-acting substances such as “anabolic agents”, which positively affect muscle mass, strength and recovery. The several doping substances discussed in this article are all classified as anabolic agents on the World Anti-Doping Agency (WADA) Prohibited List.

Clenbuterol (Clenbuterol) is a β₂-adrenergic receptor agonist. In China, it is better known by a catchier name: “lean-meat powder”.

In the early 1980s, a US pharmaceutical company discovered by chance that clenbuterol could not only significantly promote growth and protein synthesis, but also reduce fat and increase lean-meat percentage. In other words, it could make pigs “both lean and heavy” in a remarkably short time, and it was therefore widely adopted as a feed additive in the livestock industry.

On the same principle, clenbuterol can also increase muscle mass in humans or, in the short term, enhance cardiac function and basal metabolic rate, which is why it is listed on the WADA Prohibited List.

However, clenbuterol persists in animal bodies for a long time and is difficult to break down even under high-temperature cooking, and it has caused numerous food poisoning incidents.

In 2001, nearly a thousand people in Guangdong Province were hospitalised after eating pork contaminated with “lean-meat powder”, suffering symptoms including dizziness, vomiting and tremors. In 2006, more than 300 people in Shanghai were poisoned by “lean-meat powder” in pork. In February 2009, a “lean-meat powder” poisoning incident struck Guangzhou, hospitalising more than 70 people; authorities subsequently detected 63 problem pigs.

In recent years, similar large-scale poisoning incidents have ceased to make headlines, yet reports of illegal “lean-meat powder” use still surface occasionally. In 2021, CCTV’s 315 Gala exposed a farm in Qing County, Hebei, for feeding clenbuterol to sheep.

In fact, as early as 1997, China’s Ministry of Agriculture explicitly banned clenbuterol and ractopamine—two types of “lean-meat powder”—from use in feed and livestock production; in 2002, a further seven types of “lean-meat powder” were banned from use in feed and animal drinking water.

Yet illegal use in the livestock industry persists despite repeated bans.

The first challenge is source control. In 2011, the Shuanghui “lean-meat powder” pork scandal revealed that pharmaceutical companies were able to repurpose clenbuterol hydrochloride from asthma medication into “lean-meat powder”. Ultimately, 48 people were sentenced in this case; the two individuals responsible for processing were convicted of the crime of endangering public safety by dangerous means and sentenced to death with a reprieve and life imprisonment, respectively.

Although the 2019 National Routine Monitoring of Agricultural Product Quality and Safety reported a 99.9% pass rate for “lean-meat powder” spot checks on livestock products, higher-precision laboratory data tell a different story: “lean-meat powder” has never truly left our tables.

Also in 2019, research teams from two universities in Jilin Province tested hundreds of meat samples from across the province. The combined detection rate for three types of “lean-meat powder” was 11.36%, with a clenbuterol detection rate of 6.37% and an average residue level of 0.85 μg/kg—well above the maximum safe residue level of 0.2 μg/kg recommended by the Codex Alimentarius Commission (CAC).

At present, the lowest clenbuterol concentration detectable by the national standard laboratory method is 0.5 μg/kg, which is above the maximum safe residue level of 0.2 μg/kg, and the rapid tests commonly used in market supervision are even less precise. Therefore, “not detected” does not mean that food is free of clenbuterol, let alone that it is safe.

The higher-precision testing used by the World Anti-Doping Agency has further exposed the widespread prevalence of doping contamination in meat products.

WADA has cited a 2012 study by the German Sport University Cologne, in which researchers collected urine samples from 28 volunteers who had just returned from China. Using a method with a limit of detection of 1 pg/ml—200 times more sensitive than the minimum limit of detection of 0.2 ng/ml specified by WADA—clenbuterol was detected in 79% of the samples.

In the 2016 and 2017 cases of clenbuterol-positive Chinese swimmers questioned by The New York Times, WADA’s review found that the levels in the three Chinese athletes who tested positive were extremely low, and the cases were determined to stem from consumption of contaminated meat. According to WADA’s records, clenbuterol has caused 420 cases worldwide of athletes testing positive due to meat contamination.

In 2021, a WADA document explicitly noted that clenbuterol contamination was widespread in meat from Guatemala, Mexico and China—despite clenbuterol having been banned domestically for 24 years at the time.

Such independent studies prompted WADA to revise its standards in 2019, so that positive results for low-dose clenbuterol in urine (below 5 ng/ml) no longer need to be reported.

For years, Chinese athletes have been required to exercise particular caution when eating outside. In 2016, the national table tennis team issued a written order requiring players to eat only food provided at training bases, forbidding them from consuming food or drink of unknown origin—especially meat—and even banning them from eating anything gifted by relatives or friends.

II. Trenbolone and Hormone-Fattened Cattle

This past March, US track and field athlete Erriyon Knighton tested positive for trenbolone, and behind that finding lies a similar story.

Trenbolone, dubbed “the holy grail of competition prep” in the bodybuilding world, is an androgen and an anabolic-androgenic steroid (AAS) that promotes protein synthesis while suppressing protein degradation, producing a muscle-building effect. It has not been approved for clinical use in humans, yet some people still use it illicitly for muscle gain.

The adverse effects of AAS on human health include harmful changes in cholesterol levels, acne, high blood pressure, liver damage and left ventricular hypertrophy; their impact on the heart can lead to myocardial infarction and stroke. AAS can also cause conditions linked to hormonal imbalance, such as gynaecomastia and testicular atrophy in men, as well as irreversible virilisation in women and children.

The livestock industry typically administers trenbolone to cattle during the fattening stage to increase muscle mass and shorten the time until beef cattle reach market weight. The United States is one of a handful of countries that have approved trenbolone for use in farmed animals.

Since the 1950s, the United States has approved several hormones for promoting animal growth, including trenbolone, as well as natural androgens, oestrogens and progestogens and their synthetic analogues, sometimes collectively referred to as “hormonal growth promotants” (HGPs). According to some data, approximately 90% of US livestock operations use these hormones; on large-scale farms the rate approaches 100%.

Although the US and other countries maintain that synthetic hormone residues in beef do not pose a health risk to humans, the EU has always taken a cautious stance.

The European Commission’s Scientific Committee on Veterinary Measures relating to Public Health stated in a report: ‘The endocrine balance in the human body is fragile; (these hormones) and their metabolites have potential genotoxicity… and exposure to exogenous hormones may disrupt this delicate equilibrium.’ In other words, such hormones may cause endocrine disruption.

Based on this precautionary approach, the EU has banned imports of beef containing six growth-promoting hormones—including trenbolone—since 1989. The import ban sparked a long-standing trade dispute between the EU and the United States; the two sides battled over whether the ban violated free-trade principles for nearly 20 years, a clash the media dubbed the “beef war”.

Currently, China completely prohibits the use of growth-promoting hormones in livestock farming, and trenbolone is explicitly included on the list of banned veterinary drugs, with no detectable residue permitted in food.

III. Banned = Zero Use?

Yet the “zero tolerance” requirement has failed to eradicate the use of trenbolone in China’s livestock industry.

In 2021, Professor Ying Guangguo’s team at South China Normal University detected traces of trenbolone in wastewater and manure from two pig farms in southern China. Two other papers co-authored by Professor Ying in 2012 had also reported trenbolone detections at multiple farms across the region.

Since trenbolone cannot be produced through an animal’s own metabolism, illegal supplementation during farming is certain. Moreover, several of these studies also detected methyltestosterone, diethylstilbestrol and other banned hormones.

Aquaculture is another major source of hormone misuse.

Although the Ministry of Agriculture and Rural Affairs prohibits the addition of hormone substances to water or feed, a 2015 study found that feed samples from aquaculture sites near Hailing Island, Yangjiang, Guangdong, contained multiple synthetic steroids, including trenbolone—clear evidence of illegal hormone supplementation in feed. In addition, multiple studies have detected synthetic hormones in waters near farms in southern China.

Hormones used in livestock, poultry and aquaculture farming all eventually discharge into water bodies, causing pollution and entering the human body through the environment and the food chain. Research has found that in areas with high farming density, steroid hormone concentrations in rivers may exceed safe levels, affecting the growth and reproduction of aquatic organisms. Trenbolone detected in Lake Tai waters in 2016 was closely linked to the inflow of aquaculture wastewater.

Beyond illegal use, what other practices in livestock farming may give rise to hormone misuse?

Although hormones may not be used for growth promotion in livestock, they can be administered for therapeutic purposes. However, “treatment” goes beyond medicating sick animals—it can also be interpreted as regulating reproductive functions: one injection to trigger oestrus, another to induce ovulation, and hormones may also be used to maintain pregnancy, induce parturition or stimulate lactation. Whether existing veterinary hormones are used for their intended purposes, and whether safe dosage levels and withdrawal periods are observed, all remain grey areas.

Another grey area is synthetic versions of naturally occurring hormones. Hormones such as testosterone and oestradiol, which can be used to promote weight gain during the fattening stage, are also produced naturally within the animal’s own body, making it difficult to determine whether illegal supplementation has occurred.

Unfortunately, residues of synthetic hormones in animal products such as meat, eggs and dairy currently lack regulatory oversight. With the exception of dexamethasone, synthetic hormones are not included in the scope of the State Administration for Market Regulation’s food safety supervisory spot-check list. As for hormone residue levels in ordinary people’s everyday food, even less is known.

IV. Metandienone’s Unknown Risks: A “Human Drug for Veterinary Use”

The doping controversies have effectively become litmus tests for food contamination, and the risks posed by the steroid hormone metandienone (Metandienone, also known as Dianabol) may already have quietly emerged.

In October 2022, two Chinese swimmers tested positive for metandienone. WADA confirmed that the China Anti-Doping Agency had examined hundreds of meat samples from various sources, dozens of which contained detectable metandienone residues, and on this basis determined that the low doses detected originated from food contamination.

If trenbolone is “a vet drug for human use”, then metandienone is “a human drug for veterinary use”. Like trenbolone, metandienone is also an androgen, widely used by bodybuilding enthusiasts, yet it is not a standard veterinary hormone. Few researchers had previously paid attention to its use in livestock farming, and the contamination of food products by metandienone is almost entirely a blind spot.

A 2023 study found metandienone residues in beef on the Russian market. The authors suggested that although metandienone is not a standard veterinary drug, it is inexpensive and readily available on the market, so it may also be used in animals.

WADA is reported to have launched an investigation earlier this year to assess metandienone contamination in meat from China and other countries.

As the saying goes, if you spot one cockroach, there are likely a hundred more in the room.

From “lean-meat powder” to trenbolone, from synthetic growth-promoting hormones to a host of further unknown risks from unapproved drug use—testing precision and cost, and the pace at which regulations and standards keep up, all constrain the capacity for effective oversight.

Faced with a bewildering number of problematic chemicals, the system risks falling into a perpetual cycle in which “those who test for drugs” can never outrun “those who use them”, leaving regulators forever chasing from behind. Curbing hormone misuse at source and eliminating food safety hazards remains a long and arduous undertaking.

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Foodthink Author

Wang Hao

Foodthink editor, devoted sports fan during major tournaments, Big Mac enthusiast who dubs them “old Beijing cuisine”, and someone who prays never to bite into a hormone-tainted beef patty.

 

 

 

Editors: Ze’en, Tianle