Olympic Doping Controversy: Exposing Hormone Abuse in Livestock Farming

The Paris Olympics closed last week, but the dust has yet to settle on the doping controversies. The turmoil involved at least three incidents related to food safety:

Ultimately, all three incidents were determined to be caused by the consumption of meat products “contaminated” with doping agents, rather than the athletes intentionally taking them. Consequently, the athletes involved were not penalised and were permitted to compete.

Whether these explanations are the truth or merely excuses is something the average person cannot verify. However, over the years, the World Anti-Doping Agency (WADA) has identified thousands of similar cases, indicating that meat contamination caused by doping agents is widespread globally, including in China.

Why does meat contain doping agents? And are ordinary people, like athletes, equally likely to inadvertently consume meat containing these substances?

By tracing the specific doping substances involved in this controversy and carefully reviewing various investigative reports, media coverage, and dozens of academic studies, we have uncovered overlooked food safety risks within China’s livestock industry. The issues exposed either differ significantly from the official line provided by government food safety departments, or fall into areas where government supervision is lacking or has not been disclosed to the public.

Key findings include:

Despite being banned long ago and included in routine market testing with strict enforcement by regulatory authorities, the “lean meat powder” clenbuterol continues to be used.

Growth hormones such as trenbolone are being used illegally to fatten livestock, revealing blind spots in regulation;

Methandienone, although a hormone used by humans, has been detected in meat during anti-doping tests.

I. Clenbuterol: Two Decades of Persistent Ban-Defiance

A more accurate term for doping agents is “performance-enhancing drugs” (PEDs). These include short-acting drugs that increase an athlete’s alertness and physical performance during competition, as well as long-term agents, such as “anabolic agents” that positively affect muscle mass, strength, and recovery. Several of the substances mentioned in this article are classified as anabolic agents on the WADA Prohibited List.

Let us start with clenbuterol, the substance that once led to a one-year ban for swimmer Ning Zetao.

Clenbuterol (Clenbuterol) is a beta-2 adrenergic agonist. In China, it is better known by a more notorious name: “lean meat powder” (shòuròujīng).

In the early 1980s, a US pharmaceutical company accidentally discovered that clenbuterol not only significantly promoted growth and protein synthesis but also reduced fat and increased the lean meat ratio. In other words, it could make pigs “lean and heavy” in a short space of time, leading to its widespread use as a feed additive in the livestock industry.

Based on the same principle, clenbuterol can increase muscle mass in humans or improve cardiac function and basal metabolic rate in the short term, which is why it is included on WADA’s prohibited list.

● A clenbuterol test card. Source: Internet

However, clenbuterol remains in the animal’s body for a long time, and its stability is difficult to break down even with high-temperature cooking, which has led to numerous food poisoning incidents.

In 2001, nearly a thousand people in Guangdong were hospitalised with dizziness, vomiting, and tremors after eating pork containing lean meat powder. In 2006, over 300 people in Shanghai suffered lean meat powder poisoning from pork. In February 2009, a lean meat powder poisoning incident occurred in Guangzhou, resulting in over 70 hospitalisations; subsequent tests by relevant departments detected 63 problematic pigs.

In recent years, similar large-scale poisoning events have no longer made the headlines, but reports of the illegal use of lean meat powder still appear 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 the use of two types of “lean meat powder”—clenbuterol and ractopamine—in feed and livestock growth; in 2002, a further seven types of “lean meat powder” were banned from feed and animal drinking water.

Yet, illegal use within the livestock industry persists despite these bans.

● According to a 2011 CCTV investigation into the Shuanghui ham sausage lean meat powder case, farmers using clenbuterol at a cost of 1 yuan could increase their income by 40-60 yuan. Source: Website screenshot

Firstly, there is the challenge of managing the source. In 2011, the Shuanghui “lean-meat powder” pork scandal revealed that pharmaceutical companies were capable of converting clenbuterol hydrochloride, used in asthma medications, into “lean-meat powder”. Ultimately, 48 people were convicted; the two individuals responsible for the processing were sentenced to a suspended death sentence and life imprisonment, respectively, for “endangering public safety by dangerous means“.

Although routine national monitoring of agricultural product quality and safety in 2019 indicated a 99.9% pass rate for lean-meat powder spot-checks in livestock products, data from higher-precision laboratory tests told a different story: lean-meat powder has never truly left our dinner tables.

Also in 2019, research teams from two universities in Jilin tested hundreds of meat samples from Jilin Province. The results showed a combined detection rate of 11.36% for three types of lean-meat powder, with clenbuterol specifically detected in 6.37% of samples. The average residue level was 0.85μg/kg, exceeding the maximum safe residue limit of 0.2μg/kg recommended by the Codex Alimentarius Commission (CAC).

Currently, the lowest concentration of clenbuterol detectable by laboratory methods specified in national standards is 0.5μg/kg—already higher than the maximum safe residue limit of 0.2μg/kg. The rapid tests commonly used by market regulators are even less precise. Consequently, a “not detected” result does not guarantee that a food product is free of clenbuterol, making it increasingly difficult to ensure food safety.

● Public notice of passing results for rapid food tests for clenbuterol and ractopamine at a market in Beijing. Photo: Foodthink

Higher-precision testing used by the World Anti-Doping Agency (WADA) has further revealed the prevalence of doping contamination in meat products.

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

Regarding the 2016 and 2017 cases of clenbuterol-positive results among Chinese swimmers questioned by The New York Times, WADA’s review found that the levels in three of the athletes were extremely low, concluding that they had consumed contaminated meat. According to WADA statistics, clenbuterol contamination in meat has caused 420 positive test results among athletes globally.

A 2021 WADA document explicitly mentioned that meat in Guatemala, Mexico, and China is commonly contaminated with clenbuterol, despite the substance having been banned domestically in China for 24 years at the time.

Similar independent research forced WADA to revise its standards in 2019: positive results for low doses of clenbuterol in urine (below 5ng/ml) no longer need to be reported.

● Left: The ban on eating out for the National Table Tennis Team. Source: Internet. Right: An advertisement for ‘exclusive’ safe meat supplied to athletes by a grain and oil enterprise. Photo: Foodthink

For a long time, Chinese athletes have been required to be exceptionally cautious when eating out. In 2016, the table tennis team explicitly required members to eat only food from the training base and avoid food and drink of unknown origin, particularly meat—even gifts from relatives and friends were forbidden.

II. Trenbolone and Hormone-Fed Beef

● Erriyon Knighton tested positive for trenbolone in March 2024. The US Anti-Doping Agency ruled that it was due to the consumption of contaminated meat and lifted his ban, allowing him to compete in the Paris Olympics. Source: CGTN

In March this year, the positive test for ‘trenbolone’ by American track and field athlete Erriyon Knighton followed a similar story.

Trenbolone, known in bodybuilding circles as a ‘holy grail’ for contest prep, is an androgen and a type of anabolic-androgenic steroid (AAS). It increases protein synthesis and reduces degradation, thereby achieving muscle growth. While not currently approved for human clinical use, some still use it privately for muscle gain.

The negative impacts of AAS on human health include harmful changes in cholesterol levels, acne, hypertension, liver damage, and left ventricular hypertrophy; its effects on the heart can lead to myocardial infarction and stroke. AAS may also cause diseases related to hormonal imbalance, such as gynaecomastia and testicular shrinkage in men, and irreversible masculinisation in women and children.

The livestock industry typically uses trenbolone during the fattening stage of beef cattle to increase muscle mass and shorten the time to market. The United States is one of the few countries that approve the use of trenbolone in livestock.

● A hormone implant being installed in the ear of a Holstein cow. Trenbolone is implanted into beef cattle in this manner, releasing slowly over several months. Source: AGDaily

Since the 1950s, the US has approved several hormones to promote animal growth, including trenbolone, as well as natural androgens, oestrogens, progestogens, and their synthetic substitutes, collectively known as ‘Hormonal Growth Promoters’ (HGPs). Data suggests that approximately 90% of US farms use these hormones, with the rate approaching 100% in large-scale operations.

Although countries like the US insist that synthetic hormone residues in beef do not harm humans, the European Union has always maintained a cautious stance.

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

Based on this precautionary approach, the EU has banned the import of beef containing six growth-promoting hormones, including trenbolone, since 1989. This import ban led to a long-standing trade dispute between the EU and the US, with both sides battling for nearly 20 years over whether the ban violated free trade principles—an ordeal dubbed the ‘beef war’ by the media.

● A scene from the beef war: Europe banned US beef imports, and the US imposed retaliatory tariffs on European agricultural products. On 12 August 1999, French farmer José Bové and his family wrote ‘McDonald’s Get Out, Save Roquefort Cheese!’ on the roof of a McDonald’s under construction as a protest. Source: Actipedia

Currently, our country completely prohibits the use of growth-promoting hormones in livestock farming. Trenbolone is explicitly listed as a prohibited veterinary drug and must not be detected in food.

III. Banned = Zero Use?

The strict ‘zero tolerance’ requirement has failed to eradicate the use of trenbolone in the domestic livestock industry.

In 2021, a team led by Professor Ying Guangguo from South China Normal University found traces of trenbolone in the wastewater and faeces of two pig farms in South China. Two other papers Professor Ying participated in in 2012 also showed that trenbolone had been detected in several farms across South China.

Since trenbolone cannot be produced through an animal’s own metabolism, it is certain that illegal additions occurred during the farming process. Furthermore, other banned hormones, such as methyltestosterone and diethylstilbestrol, were also found in these studies.

Aquaculture is another major source of hormone abuse.

Although the Ministry of Agriculture and Rural Affairs prohibits adding hormones to water and feed, a 2015 study showed that various synthetic steroids, including trenbolone, were detected in feed samples from aquaculture farms near Hailing Island in Yangjiang, Guangdong—clear evidence of the illegal addition of hormones to feed. Additionally, several studies have detected synthetic hormones in the waters of farms in South China.

Hormones used in livestock and aquaculture eventually discharge into water bodies, causing pollution and being ingested by humans through the environment and food. Research has found that in areas with high farming density, steroid hormone concentrations in river channels may exceed safety limits, affecting the growth and reproduction of aquatic organisms. In 2016, trenbolone detected in Lake Tai was closely linked to the inflow of aquaculture wastewater.

● Global steroid hormone emission intensity map, which is highly correlated with the density of livestock farming. China is also one of the regions with severe steroid pollution. Source: https://doi.org/10.1016/j.scitotenv.2021.145558

Beyond illegal use, what other scenarios in the livestock industry might lead to the abuse of hormones?

While hormones may not be used for growth promotion in livestock, they are permissible for treatment. However, ‘treatment’ does not only refer to medicating sick animals; it can also be interpreted as regulating reproductive functions: a shot for oestrus, another for ovulation, or hormones used for maintaining pregnancy, inducing labour, and stimulating lactation. Whether current veterinary hormones are used for their prescribed purposes, and whether safety dosages and withdrawal periods are followed, remains a grey area.

Another grey area is the use of synthetic versions of natural hormones. For example, hormones such as testosterone and oestradiol can be used to increase weight during the fattening process; because these hormones occur naturally in an animal’s body, it is difficult to determine if they have been illegally administered.

● In 2022, the Ministry of Agriculture and Rural Affairs tested for residues of six steroid hormones, including clenbuterol, during the slaughtering process, but the data were not made public, and they have not been included in the testing scope for the past two years.

Regrettably, there is currently a lack of oversight regarding synthetic hormone residues in animal products such as meat, eggs, and milk. With the exception of dexamethasone, synthetic hormones are not included in the food safety inspection lists of the State Administration for Market Regulation. Consequently, the extent of hormone residues in the daily diet of the average person remains unknown.

IV.The Unknown Risks of Metandienone: ‘Human Medicine for Animal Use’

The doping scandal has effectively become a litmus test for food contamination. The risks associated with the steroid hormone metandienone (also known as Dianabol) may have already quietly surfaced.

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

If trenbolone is ‘veterinary medicine for human use’, then metandienone is ‘human medicine for veterinary use’. Like trenbolone, metandienone is an androgen widely used by bodybuilding enthusiasts, but it is not a standard veterinary hormone. Previously, few researchers had noted its application in the livestock industry, leaving the issue of metandienone food contamination almost entirely in a blind spot.

A 2023 study found residues of metandienone in beef on the Russian market. The authors of the paper suggest that although metandienone is not a conventional veterinary drug, its low cost and ease of availability on the market make it a likely candidate for veterinary use.

It is reported that WADA launched an investigation early this year to assess the extent of metandienone contamination in meat across China and other countries.

● Fitness influencer ‘Changshu Arnold’ and his drug logs, which include several of the muscle-building dopants mentioned in this article. Due to the blind use of excessive hormone doses, he not only suffered health problems but failed to achieve a bodybuilding physique, earning him the mocking nickname ‘the most unsightly bodybuilder’. Image source: the internet

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

From clenbuterol to trenbolone, and from artificial growth hormones to further unknown pharmaceutical risks, the ability to regulate is constrained by detection precision and cost, as well as the speed at which regulations and standards are updated.

Faced with a myriad of problematic chemicals, it is easy to fall into a cycle where those detecting the drugs cannot keep pace with those administering them, leaving regulators in a perpetual state of catch-up. Finding a way to restrict hormone abuse at the source and resolve food safety hazards remains a formidable challenge.

References

https://news.sina.com.cn/c/2001-11-16/401083.html

https://news.sina.com.cn/c/h/2006-09-17/103311030026.shtml

https://news.sina.com.cn/s/2021-03-18/doc-ikkntiam4914837.shtml?from=zixun_xinwen

https://finance.china.com.cn/news/20190805/5046454.shtml

https://kns.cnki.net/kcms2/article/abstract?v=G7eKQ1uxNXd2rD3dEPMAnKIOj46a_v7JL8aD7eyL1rJpfoxlL64fsTdt9glEOLKi4OS6fgCHD3h_VcTL7QdPK8KqoT_ZiKTA78351YA30zUJ1MVohFeljOFwPc2Wy05rjSfqsbDeDjAKPnNEMXVIAgrRiOPyGB93Tj_VkEkl4UVhEFsXFVOMBu4_Um4c95t-P06vdbgjX5_Bvo6x

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/dta.1330

https://www.wada-ama.org/sites/default/files/resources/files/tl23_growth_promoters_eng_2021_0.pdf

https://www.jiemian.com/article/999725.html

https://www.chinada.cn/contents/6/6820.html

https://en.wikipedia.org/wiki/Trenbolone

https://www.indianjournals.com/ijor.aspx?target=ijor:jms&volume=12&issue=2&article=001&type=pdf