Green Tea Helps Steroid-Using Athletes Beat Anti-Doping Test

Researchers at Kingston University in London have discovered that drinking green tea or white tea can help steroid-using athletes beat a commonly used anti-doping test. Declan Naughton and colleagues reported that compounds known as catechins may allow athletes to use the anabolic steroid “testosterone” and avoid detection.

The testosterone:epitestosterone ratio (T:E ratio) test is frequently used to screen drug-tested athletes for the exogenous administration of testosterone. It determines the ratio of testosterone glucuronide to epitestosterone glucoronide in an athlete’s urine.

Exogenous administration of testosterone does not influence the levels of epitestosterone. Therefore, a testosterone-using athlete should have a higher ratio of testosterone metabolites in their urine when compared to epitestosterone.

The catechins found in green tea inhibit an enzyme called UGT2B17. This enzyme is responsible for attaching glucuronic acid to testosterone. By inhibiting UGT2B17, an athlete will excrete less testosterone glucoronide in their urine. This will help a testosterone-using athlete produce a normal ratio.

Most individuals have a ratio of 1:1 testosterone to epitestosterone. But ratios as high as 4:1 are not uncommon. The World Anti-Doping Agency (WADA) considers a ratio of 4:1 to be a putative indicator of doping subject to confirmation by another anti-doping procedure known as carbon isotope ratio (CIR) testing.

The T:E ratio test can not tell the difference between testosterone produced by the body and testosterone that has been introduced via injections, pills or creams.

CIR testing can detect exogenous testosterone of plant origin. However, if athletes are able to successfully pass the T:E ratio test, they are not subject to the more definitive CIR test.

Therefore, if athletes can avoid detection in the T:E ratio test, they can get away with the administration of exogenous testosterone.

While green tea may provide another method for athletes to beat the T:E ratio test, athletes have regularly beat the T:E ratio screen through other means.

Professor Charles Yesalis, a noted steroid expert and epidemiologist at Pennsylvania State University, has long been outspoken about the so-called “testosterone loophole“.

Even Don Catlin, the former director of UCLA’s Olympic Analytical Testing Lab and founder of the Anti-Doping Research Institute, has acknowledged that athletes can use testosterone without getting caught even though anti-doping testers know how they do it.

“I could figure out how to take a fair amount of testosterone and you’d never catch me, and if I can say that, a lot of others can too,” admitted Catlin.

Athletes simply add epitestosterone to their drug protocol in order to maintain the 4:1 ratio. However, they must keep the absolute levels of urinary testosterone gluconoride and epitestosterone gluconoride below the 200ng/mL limit allowed by WADA.

“The cream” used by BALCO a decade ago was simply a variation of the testosterone and epitestosterone cocktail that had been historically used by athletes for decades to fool drug testers.

BALCO athletes used a unique transdermal delivery system to administer a customized testosterone and epitestosterone formula. One gram of “the Cream” contained 5 milligrams epitestosterone for every 100 milligrams of testosterone in a 1:20 ratio according to Victor Conte. This allowed BALCO athletes to use testosterone without getting caught.

Even after the $60+ million government investigation into BALCO, the $20 million Mitchell report on steroid use by MLB players and the sensationalistic Congressional hearings on steroid in baseball and other professional sports, the “testosterone loophole” has not been closed. The “cream” is just as effective as ever for a professional baseball player.

As if the T:E ratio test didn’t suck enough as an effective anti-doping tool, four years ago researchers at the Karolinska University Hospital in Stockholm discovered that some athletes can inject impressive amounts of testosterone and not fail the T:E ratio if they lacked the gene that produces the UGT2B17 enzyme.

Approximately 40% of these “genetically gifted” athletes could take a whopping injection of 500mg of testosterone enanthate without raising flags from current WADA doping controls.

And this genetic anomaly is relatively common and is more common in certain ethnic groups. Thus, an athlete’s ethnicity may give them a doping advantage.

  • 78.0% – Mulatto (Brazilian)
  • 66.7% – Eastern Asian (Korean)
  • 57.3% – Cape Colored (Cape Town, South Africa)
  • 37.6% – Mexican Mestizo
  • 30.4% – Asian Pacific (Southeast Asian/Southern Chinese, Asian Indian, Japanese)
  • 29.1% – Black (African Americans, African Blacks, South/Central American Blacks)
  • 9.3% – White Caucasian (Swedish)
  • 3.5% – White Caucasian (primarily European)

Four years ago, I asked “Could there be a rogue chemist who discovered a pharmaceutical drug that can block the UGT2B17 enzyme?” I guess a rogue chemist wasn’t required. Little did I know that green tea or white tea could effectively block UGT2B17. While the UGT2B17-blocking effect of green tea is news to the scientific community, somehow I suspect this “secret” has been common knowledge in some elite athletic circles.

The use of testosterone remains one of the most popular methods used by steroid-using athletes to avoid detection. The “testosterone loophole” will continue to be exploited as long as the T:E ratio test is used as the primary screen for testosterone use.

Green tea helps athletes get away with using testosterone
Green tea helps athletes get away with using testosterone


Jenkinson, C. et al. (2012). Dietary green and white teas suppress UDP-glucuronosyltransferase UGT2B17 mediated testosterone glucuronidation. Steroids.

The anabolic steroid testosterone can be used by athletes to enhance athletic performance and muscle growth. UDP-glucuronosyltransferase (UGT2B17) is the key enzyme involved in the glucuronidation of testosterone to testosterone glucuronide, which also serves as a marker for the testosterone/epitestosterone (T/E) ratio detect testosterone abuse in sport. Inhibitors of testosterone glucuronidation could have an impact on circulating testosterone levels, thus aiding performance, as well as potentially affecting the urinary T/E ratio and therefore masking testosterone abuse. Previous reports have revealed that non-steroidal, anti-inflammatory drugs, diclofenac and ibuprofen, inhibit the UGT2B17 enzyme. The aim of this study is to analyse dietary tea samples for inhibition of testosterone glucuronidation and, where inhibition is present, to identify the active compounds. Analysis of testosterone glucuronidation was conducted by performing UGT2B17 assays with detection of un-glucuronidated testosterone using high performance liquid chromatography. The results from this study showed that testosterone glucuronidation was inhibited by the green and white tea extracts, along with specific catechin compounds, notably: epicatechin, epigallocatechin gallate (EGCG) and catechin gallate. The IC50 inhibition value for EGCG was determined, using a Dixon plot, to be 64 μM, equalling the most active NSAID inhibitor diclofenac. Thus, common foodstuffs and their constituents, for the first time, have been identified as inhibitors of a key enzyme involved in testosterone glucuronidation. Whilst these common compounds are not substrates of the UGT2B17 enzyme, we showed that they inhibit testosterone glucuronidation which may have implications on current doping control in sport.

Conte, Victor. (VictorConte). “”The cream” contained 5 mgs per gram of epitestosterone, so the T/E ratio was 20 to 1 RT @millardbaker: @VictorConte how much epi-t.” 27 Feb 12, 9:09 a.m. Tweet.

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