England’s build-up to their pivotal FIFA World Cup Round of 16 encounter with Mexico has sparked one of the tournament’s most unexpected discussions.
As Thomas Tuchel’s squad prepares to face the hosts at the iconic Azteca Stadium in Mexico City, attention has turned to the possibility that England players could be allowed to use the blue pill in an effort to lessen the impact of the city’s high-altitude conditions.
The conversation underscores the unique test awaiting the Three Lions, who must contend not only with Mexico but also with one of the most physically demanding venues in world football.
Why high altitude is England’s biggest opponent
Mexico City’s renowned Azteca Stadium sits about 2,240 metres (7,220 feet) above sea level, making it one of the most elevated and recognisable stadiums on the global football stage.
At that altitude, reduced oxygen levels place far greater strain on the body during high-intensity exercise.
Players tire more quickly, recovery takes longer, and symptoms such as dizziness, headaches, and shortness of breath can affect even the fittest athletes.
Thomas Tuchel has already recognised the scale of the challenge confronting his players. After England’s hard-fought 2-1 win over DR Congo, the German coach admitted there simply is not enough time for the squad to properly adapt to the altitude before facing Mexico, talkSPORT reports.
With Mexico entering the match after four straight games without conceding a goal, any physical advantage could make a crucial difference.
🤯🏴 BREAKING: England’s national team has arrived in Mexico City ahead of their game against the Mexican National Team this Sunday.
“England your time is over”. 🍿🏆 pic.twitter.com/yPFHOlu7Lm
— All Fútbol MX 🇲🇽 (@AllFutbolMX) July 4, 2026
The science behind the blue pill’s unexpected sporting use
While the medication is widely known for treating erectile dysfunction, that was not the purpose for which it was originally developed.
Its active ingredient, sildenafil, was first created to treat patients with high blood pressure.
Because sildenafil helps relax and widen blood vessels, particularly in the lungs, sports medicine specialists have explored its potential role in high-altitude competition. By improving blood circulation and lowering pressure in the lungs, the drug may help the body deliver oxygen more effectively when oxygen is limited.
Scientific research has produced mixed findings. A study published in 2015 found that some athletes recorded performance gains of more than 35 percent at elevations exceeding 3,800 metres.
However, the same research also determined that those benefits decline considerably below 4,000 metres, suggesting that many competitors are likely to see little or no meaningful improvement.
Since Mexico City is well below that altitude, questions remain over whether sildenafil would offer any real competitive benefit.
Even so, similar approaches have been explored before. In 2019, Argentine club Unión de Santa Fe reportedly examined the possibility of using sildenafil before fixtures played at high altitude in Ecuador.
Why FIFA and WADA permit its use
Importantly, the blue pill is fully permitted under existing sporting rules, according to Tuko Sports reports. Sildenafil does not appear on the World Anti-Doping Agency’s list of prohibited substances for 2026 after extensive assessments of its impact on athletic performance.
WADA determined that the medication does not provide a significant competitive advantage at sea level or under standard playing conditions.
Consequently, FIFA places no restrictions on players who need or choose to use sildenafil for legitimate medical reasons. That does not mean England will be reaching for “Vitamin V” before kickoff.
Rather, the debate illustrates the extraordinary measures teams consider when preparing for matches played under challenging environmental conditions. Mexico, meanwhile, heads into the contest with every possible advantage.
The tournament co-hosts have registered four successive clean sheets, suffered only two defeats in 89 matches at the Azteca, and head into the Round of 16 in high spirits after a convincing 2-0 victory over Ecuador.
For England, conquering the demands of the altitude could be just as formidable a task as defeating Mexico on the pitch.
