Does Viagra enhance athletic performance? Not at sea level. In a controlled trial in trained cyclists, sildenafil — the medicine in Viagra — "had no effects on any cardiovascular or performance measures" at sea level (Hsu et al., J Appl Physiol 2006). The gains people quote were measured in thin air, at real or simulated altitude, and even there they came from some riders, not all, and did not show up in later trials.
Does Viagra improve performance at sea level?
No. Ten trained men cycled at sea level and at a simulated altitude of 3,874 m after a placebo, 50 mg or 100 mg of sildenafil; at sea level it changed nothing, neither the heart and circulation measures nor the time trial (Hsu, 2006). In a second trial, 11 volunteers took 100 mg an hour before testing, and at normal oxygen levels "sildenafil did not affect performance" (Toro-Salinas et al., Int J Sports Med 2016). The 15% and 39% gains often quoted for the first study were both measured in thin air, as the next sections show. Tadalafil, the medicine in Cialis, did no better at normal oxygen levels; its trials are on is Cialis useful for running?
Does Viagra help at high altitude?
Sometimes, and not for everyone. At altitude, low oxygen narrows the blood vessels of the lungs and raises the pressure in them, which "could be a limiting factor for physical performance" (Toro-Salinas, 2016), and sildenafil widens those vessels (Hsu, 2006). In 14 mountaineers and trekkers, 50 mg reduced this hypoxic pulmonary hypertension and raised their maximum workload, both in low-oxygen air at low altitude and at Mount Everest base camp (Ghofrani et al., Ann Intern Med 2004). At a simulated 3,874 m, it cut the cyclists' 6 km time-trial time by 15% on average (Hsu, 2006).
Later trials did not repeat that. In 35 endurance-trained men and women at a simulated 3,900 m, 50 mg "did not significantly improve cardiovascular hemodynamics or time-trial performance" (Jacobs et al., High Alt Med Biol 2011). At a simulated 4,000 m there were no significant differences, and the authors concluded that using sildenafil to improve performance in people not used to altitude "is not supported by our data" (Toro-Salinas, 2016). Tadalafil did not improve exercise capacity at 4,559 m either (Fischler et al., Am J Respir Crit Care Med 2009).
Who are the "responders"?
The few people who gained. When the Hsu team split its ten riders after the trial, the responders improved their time-trial performance by 39% and the others by 1.0%, and 100 mg did no better than 50 mg (Hsu, 2006). In the larger Jacobs trial, one man out of 35 improved in a meaningful way, by 36 seconds, and the authors wrote that "a very small percentage of endurance-trained men and women derive meaningful improvements" at that altitude (Jacobs, 2011). All of these were short tests in small groups; none followed athletes through weeks of training.
Is Viagra banned in sport?
No. A search of the World Anti-Doping Agency's Prohibited List for sildenafil returns no results (WADA — the Prohibited List, searched 27 September 2026). The list is updated at least once a year, and WADA asks athletes to check any substance they cannot find with their anti-doping organisation. What drug tests look for is on can Viagra be detected in drug tests?
What are the risks of taking Viagra for sport?
A fall in blood pressure, and the usual side effects. In healthy volunteers, 100 mg lowered blood pressure lying down by an average maximum of 8.4 mmHg systolic and 5.5 mmHg diastolic (Viagra PI). Dizziness and fainting are among the rarer serious side effects of ED medicines; headache, flushing, a blocked nose and indigestion are among the common ones (healthdirect — ED medicines). With nitrates for chest pain, amyl nitrite or some blood pressure medicines, sildenafil can cause "a sudden drop in your blood pressure that is hard to treat" (healthdirect — Sildenafil); amyl nitrite is "sometimes called 'poppers'" (Viagra CMI).
In Australia sildenafil "can only be supplied to Australians with a prescription" (TGA), and Viagra is approved "for the treatment of erectile dysfunction in adult males" (Viagra PI), not for sport. Taking it without erection problems has its own page: can Viagra be used recreationally? Muscle is the question of does Cialis have benefits for bodybuilding?
What is sildenafil used for besides erections?
High blood pressure in the lungs. Under the trade name Revatio, sildenafil treats pulmonary arterial hypertension (healthdirect — Sildenafil), and the PBS lists a 20 mg tablet for that disease (PBS item 9547L). The altitude studies tested the same effect on the blood vessels of the lungs (Hsu, 2006). More on what sildenafil 20 mg is used for.
The short answer
At sea level, sildenafil did not improve performance in the trials that tested it. In thin air some people gained, but larger and later trials found little or no benefit. It is not on WADA's Prohibited List, it lowers blood pressure, and in Australia it is a prescription medicine for erectile dysfunction. Other uses of Viagra beyond the bedroom are gathered in our guide to the alternative uses of Viagra.
