How long should you wait for Viagra to kick in? Usually 30 to 60 minutes, which is why it is taken about an hour before sex. "It usually starts working in 30 to 60 minutes. The effects of the medicine can last for up to 4 hours" (healthdirect). It may take longer after a heavy meal, and it works only when you are sexually aroused: "kicking in" means an erection comes more easily with stimulation, not that one appears on its own.
How soon can Viagra start working?
For some men in well under an hour. In a study of men with erectile dysfunction who took sildenafil on an empty stomach, those who reached an erection firm enough for intercourse got there in a median of 25 minutes, ranging from 12 to 37 minutes (EMA product information). The level in the blood peaks within 30 to 120 minutes, 60 minutes in the middle case, when taken without food (EMA product information). That spread is why the leaflet says "The amount of time VIAGRA takes to start working varies from person to person, but it normally takes between half an hour and one hour" (Viagra CMI).
Why take it an hour before sex?
So it has time to work. "Take your dose of VIAGRA about one hour before you intend to have sex" (Viagra CMI); healthdirect gives the same advice, "so it has time to work". The recommended dose, usually 50 mg, is taken "as needed approximately one hour before sexual activity" (EMA product information). Waiting too little is a common reason for disappointment: Australian Prescriber lists "not waiting long enough for them to work" among the things that blunt the response (Australian Prescriber).
What makes Viagra slower to kick in?
Mostly a big meal. "You may find that it takes longer to work if you have a full stomach" (healthdirect): taken with food, the peak level arrives about 60 minutes later on average and is 29% lower (EMA product information). If you want it to work sooner, take it before a meal rather than straight after one; the details are in empty stomach or after eating? Alcohol "can temporarily impair the ability to get an erection" (Viagra CMI), and anxiety and "excessive expectations of how these drugs should work" also blunt the response (Australian Prescriber). The foods and drinks that matter are in foods to avoid with Viagra.
How do you know it has kicked in?
By being aroused. Viagra "will not increase your sex drive and will work only if you are sexually excited" (Viagra CMI): without sexual stimulation there is nothing to notice. What a first dose is like, side effects included, is in what to expect when taking Viagra for the first time.
How long does it last once it kicks in?
Up to about 4 hours. As healthdirect puts it, "the ability to have an erection can occur during this 4 hour period, but the actual erection will only last for a normal period of time", and in a second study sildenafil could still produce an erection with stimulation 4 to 5 hours after the dose (EMA product information). An erection that lasts more than 4 hours needs the nearest hospital emergency department (healthdirect). How long each tablet works, and how well, is covered on our Viagra effectiveness page.
Is Cialis faster or slower?
Similar to start, far longer to last.
| Medicine | When before sex | How long it can work |
|---|---|---|
| Viagra (sildenafil) | About 1 hour | Up to 4 hours |
| Cialis (tadalafil) | At least 30 to 60 minutes; allow 1 hour the first time | Up to 36 hours |
| Vardenafil | About 25 to 60 minutes | From 25 minutes up to 4 to 5 hours |
Sources: healthdirect, Cialis CMI, EMA (vardenafil), vardenafil package leaflet.
"In some men CIALIS can work as early as 16 minutes after taking the tablet but it is recommended that you allow 1 hour the first time you take it" (Cialis CMI). The difference that matters is the window: up to 36 hours for tadalafil against up to 4 for sildenafil. More in which is better, Cialis or Viagra? and 20 mg Cialis or 100 mg Viagra?
What if it has not worked after an hour?
Give it time and stimulation, but do not take a second tablet: "You should not take any more than one sildenafil tablet in 24 hours" (healthdirect); see can I take Viagra twice in one day? Men are advised to judge it over five to six occasions (Australian Prescriber). If it keeps failing, tell your doctor, who may change the dose (Viagra CMI). Never take it with nitrates, the medicines for angina; its other risks are in can Viagra do any harm?
The short answer
Wait about an hour: Viagra usually kicks in within 30 to 60 minutes, sooner on an empty stomach, later after a heavy meal, and only with arousal. It then works for up to 4 hours. It is a prescription medicine for erectile dysfunction in Australia (healthdirect); what else to know before taking it is in our guide to ED tablets.
