Reports online suggested Thomas Tuchel's side would be able to use the drug to help combat the effects of altitude in Mexico City, which sits more than 2,000 metres above sea level.
After Tuchel declared the rumour "not true", Henderson was later asked how his side were coping with the challenging environment and he quipped, "Well, the Viagra helped, I think", before adding, "I'm joking!"
Henderson added most players were "very adaptable" and "just get on with things", whether in their attitude to altitude, noisy home fans outside their hotel, or regarding a mooted - but ultimately rejected - switch of Sunday's (Monday AEST) match time due to predicted storms.
"Like the kick-off time yesterday, whether we play at 12pm, whether we play at 6pm (local time), it doesn't really bother us," he said.
"Everything that we can't influence, like kick-off times or altitude or stuff at the hotel, is not in our control, so we just have to find solutions, which we're pretty good at.
"So for us it's about full focus on our job ahead, no excuses.
"We're ready to go and we want to come here and be the best version of ourselves tomorrow, and if we do that then we'll have a good chance of winning."
England will be unable to fully acclimatise as they would have needed to arrive 10 days ago, but they have also arrived too early for the effects on their body not to take place.
They trained for the first time on Saturday afternoon and Henderson admitted it took some getting used to.
"You can feel it a little bit, you can feel something," he said.
"I felt it a little bit, even when you just land and you come to the hotel and you're just walking around, you can feel something.
"And then today, in training, for me personally I felt that maybe in the first 10-15 minutes and then once training got going I stopped thinking about it so much and just concentrated on training.
"So hopefully when the game comes tomorrow, once the lads have done the warm-up and they've got going then the full focus is just on the game, and that's all the focus is on."
The Azteca is a famous stadium in the history of English football. Tuchel's men are the first England side to play there since Diego Maradona's 'Hand of God' moment 40 years ago.
"I think it's a huge, huge occasion," Henderson said. "It doesn't get much better or bigger than playing Mexico in Mexico City in this stadium.
"Mexico are a very good side with very good players. It'll be a really tough test, but every game in the World Cup is difficult."
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