England’s preparations for their FIFA World Cup Round of 16 meeting with Mexico have triggered an unusual talking point off the pitch after reports suggested players could use sildenafil, better known by its brand name Viagra, to help cope with the high altitude of Mexico City.
The medication has attracted attention because it is primarily prescribed to treat erectile dysfunction. However, sports physicians have also studied sildenafil for a different reason, its potential ability to improve blood flow in low-oxygen environments.
Most importantly, the drug is not prohibited under the World Anti-Doping Agency (WADA) code, meaning footballers are legally allowed to use it if prescribed by team medical staff.
Why is sildenafil being discussed?
England face Mexico at the historic Estadio Azteca, one of world football’s highest major stadiums at around 2,240 metres (7,350 feet) above sea level.
At that altitude, oxygen levels are significantly lower than at sea level, increasing the likelihood of fatigue, shortness of breath and slower recovery, particularly for players arriving from lower-altitude environments.
Medical researchers have explored whether sildenafil can improve blood circulation in the lungs, potentially reducing some effects of altitude by helping blood vessels relax. While the evidence remains mixed, the drug has occasionally been discussed as one of several medical options available to athletes competing at elevation.
The reported use is therefore linked to altitude management rather than performance enhancement in the conventional sense.
Is Viagra banned by WADA?
No.
Sildenafil does not appear on WADA’s list of prohibited substances and may be used both in and out of competition.
The anti-doping body has examined the drug over several years because of questions surrounding its possible effect on endurance performance.
However, existing scientific studies have not produced sufficient evidence to classify sildenafil as a performance-enhancing substance under normal sporting conditions, particularly at or near sea level.
As a result, athletes across sports are permitted to use it without requiring a Therapeutic Use Exemption (TUE), provided it is used in accordance with standard medical practice.
Why altitude changes the discussion
Although sildenafil offers no proven competitive advantage in most sporting environments, researchers have continued studying whether it may benefit athletes competing at high altitude.
The theory is that by widening blood vessels in the lungs, the drug could improve oxygen delivery in conditions where thinner air places additional strain on the cardiovascular system.
The scientific evidence, however, remains inconclusive.
Some studies have suggested modest benefits for certain individuals, while others have found little or no measurable improvement in endurance or athletic performance.
That uncertainty is one reason WADA has continued monitoring the research without moving to prohibit the medication.
England’s challenge at the Azteca
Regardless of any medical strategy, England face one of the tournament’s toughest assignments.
Mexico have enjoyed a formidable record at the Estadio Azteca, where visiting teams have historically struggled with both the atmosphere and the altitude.
The knockout tie comes after England needed late goals to edge past DR Congo in the previous round, while Mexico have won all four of their matches in the tournament.
For Thomas Tuchel’s side, preparation for the conditions forms only one part of the challenge.
Ultimately, success against Mexico is likely to depend far more on tactics, fitness and execution than on any medication permitted under anti-doping regulations.