Why is Viagra not working for me?

Last updated 17 August 2026

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You’ve tried Viagra, but it didn’t work.

In this situation, it’s easy to panic. Viagra is supposed to be the most effective treatment for erectile dysfunction, so if it doesn’t work for you, there’s no hope. Right?

Not true. There are plenty of reasons why Viagra might not work 100% of the time. But by listening to what we’ve got to say, you can improve your chances of Viagra working for you. And even if you follow our advice and Viagra still isn’t having the desired effect, you have options. Let’s get into it.

How does Viagra work?

Viagra, also called sildenafil, works by increasing blood flow to your penis. When you get an erection, more blood flows into your penis than flows back out into your body, which causes it to swell and get hard. Viagra helps by relaxing muscle tissue in your penis, opening up the veins and spongy tissue inside, allowing it to fill with blood more easily, making it more likely you’ll get an erection.

But, like all drugs, Viagra isn’t 100% effective. It works for some people, but for others it’s not always a winner. Let’s look at why not, but first some of your most frequently asked questions.

Can Viagra stop working?

Yes. Your body can get used to Viagra and over time it can stop working. How fast this happens depends on how often you take it, what dose you take, and your unique biology. To counter this, you can increase your dose (you should never change your dose yourself so be sure to talk to our doctors first), or you can try switching to other ED meds like Cialis or Levitra.

Does Viagra work if you have low testosterone?

Viagra may not work for men with low testosterone. Viagra combats erectile dysfunction by increasing the flow of blood to the penis, but if your erectile dysfunction is caused by low testosterone rather than problems with blood flow, Viagra won’t have any effect. You’ll have to raise your testosterone level to deal with your erectile dysfunction. Read more about low testosterone.

How long does Viagra take to work?

Viagra usually takes between 30 to 60 minutes to work. Everyone is different though, and Viagra can take longer to work for some men, up to four hours, and in some cases even longer. You may need to be patient.

Does Viagra work all the time?

No, Viagra doesn’t work all the time. There are lots of reasons why Viagra may not always work for you. You might not be aroused enough, the cause of your erectile dysfunction may change, or you may have taken your Viagra alongside a heavy meal, alcohol, or other drugs which stop it from working.

Why might Viagra not be working for you?

First off, know that you’re not alone. In research, around 30% of the men who used Viagra, or a drug like it, reported they didn’t get the full benefits.

Sometimes this is because a drug genuinely won’t work for some men. The same drug will have different effects on different people, and sometimes it won’t work at all. But often it’s not the drug that’s at fault, it’s the user taking it wrongly. And just like any other drug, you need to take Viagra properly for it to work. If Viagra isn’t working for you, it could be due to some of these reasons:

You’ve got the wrong expectations

Viagra is used to treat erectile dysfunction (ED). Lots of men wrongly believe that Viagra has other benefits too, including that it can increase your sex drive, help you last all night, and even give you a bigger erection.

These are myths. Despite what you might have heard from your friends, Viagra doesn’t do these things. If you have problems getting or maintaining an erection, Viagra could work for you. If you don’t, and you’re expecting Viagra to do something else, then you’re going to be disappointed.

You’re not waiting long enough

You should take Viagra 60 to 30 minutes before you have sex, as on average it takes this long to start working. But it can take longer, even up to four hours or more. Viagra might work for you, but it might take longer to kick in.

You’re not aroused

Viagra doesn’t make you hard automatically. You have to be in the mood for sex, your body has to be sending the signals to your penis to get hard, and Viagra makes it more likely for your erection to happen. But if you’re not in the mood, if those signals aren’t being sent, Viagra won’t be able to help.

You should kiss your partner and engage in foreplay, or whatever else turns you on, after you’ve taken Viagra, to make sure you’re aroused enough for it to work.

If you’re having problems with your sex drive and you’re finding you’re not in the mood for sex, then you could have another condition which is causing this, like low testosterone, which can stop Viagra from working. You’ll need to address this issue before Viagra can help.

You’ve taken Viagra with recreational drugs, alcohol, or food

Some recreational drugs, like cocaine and ecstasy, can cause temporary ED, as can drinking large amounts of alcohol. These substances can all stop Viagra from working. If you’re worried Viagra isn’t for you, try taking it when sober to rule out the effects of drugs and alcohol.

Taking Viagra alongside a large meal, especially a high-fat one, can slow down the speed at which the drug is absorbed by your body, which can make it take longer to work. Try taking Viagra on an empty stomach to make sure it’s not that pizza’s fault it isn’t working.

Your dose is too low

You might not be taking enough Viagra for it to work for you. Viagra comes in three different strengths, 25 mg, 50 mg, and 100 mg, with 50 mg being the usual dose prescribed. Your body may be more resistant to the effects of the drug though, and you may need to take a higher dose.

Don’t up your dose yourself. Talk to our doctors about increasing the dose and let them make the judgement. Viagra can have side effects and a trained professional is best suited to assess your circumstances.

Your erectile dysfunction isn’t caused by impaired blood flow

Viagra works best for men whose ED is caused by a physical problem which impedes the flow of blood to their penis, like high cholesterol, high blood pressure, or diabetes. But if your ED is caused by a different physical issue, such as nerve damage or low testosterone, then Viagra most likely won’t help.

If you have persistent ED, and medications like Viagra don’t work for you, then you should talk to your doctor, as you could have a serious medical condition that you need to know about.

Your erectile dysfunction is psychological, not physical

Sometimes ED isn’t caused by a physical problem at all, but by a psychological one. This is often the case in younger men in their twenties and thirties, who are healthy and fit, but still have problems with erections. Psychological issues include performance anxiety, addiction to porn or emotional problems in your relationship.

Viagra may help with some of these issues, it can take the stress out of performance anxiety for instance, but generally, Viagra won’t help with ED caused by psychological problems. You need to get to the heart of the matter, and you’ll probably do this best by talking to a mental health care professional.

Viagra just isn’t the right drug for you

Everyone is different. What works for some people doesn’t always work for others. A quirk of your biology might mean that Viagra just isn’t the right drug for you, no matter how you take it, what dose you use, and how patient you are. But don’t worry, you’ve got alternatives. Viagra is a type of ED med called a PDE5 inhibitor, but it isn’t the only one. There are other PDE5 inhibitor medications which work in similar ways, but with subtle differences, and your body may respond better to them. If you don’t get any joy with Viagra you can try vardenafil or tadalafil.

Where can I get erectile dysfunction medications from?

ED meds like Viagra, and the alternatives mentioned above, are prescription drugs, meaning you should always make sure you get them from a reputable source. FROM MARS is a registered UK pharmacy and our team of doctors will review your details and prescribe tailored ED treatments if you are medically approved. 

Beware of other websites that will sell you Viagra without a prescription, as you can’t guarantee you are buying the genuine product which could be dangerous to your health. 

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