Viagra Not Working? Here’s Why & What to Do

Viagra is effective for many men and has a strong success rate, but it does not work for everyone.

Every person’s body responds differently, so while some men get reliable results, others may find it less effective.

Even if Viagra has worked well for you in the past, it may not work every single time. Factors such as stress, tiredness, alcohol, heavy meals, underlying health conditions, timing, and arousal levels can all influence how well it works.

In short, Viagra works for most men, but not always, and not for everyone. Understanding the factors that affect its performance can help you get the best possible results.

Sometimes Viagra does not work as well as expected, and this can happen for several common reasons:

The dosage

Viagra comes in three strengths:

• 25mg – the lowest dose
• 50mg – the standard starting dose
• 100mg – the highest dose

Most men begin with 50mg. If this is not effective, speak to your prescriber about whether 100mg is suitable for you. If you are already on the 100mg dose, you will not be able to increase it further, as this is the maximum daily amount.

Further reading: Viagra dosages

Lack of arousal

Viagra will not work unless you are sexually aroused. If you are struggling with low libido, speak to your GP; conditions such as depression, stress, or diabetes can affect your sex drive.

It can also help to have an open conversation with your partner. Improving emotional closeness often leads to better sexual arousal and performance.

Taking it too early

Viagra is most effective when taken around one hour before sex. Its effects last for roughly four hours, so if you take it too early, the effects may start to wear off before you engage in sexual activity.

Taking it too late

Trying to have sex immediately after taking Viagra is also unlikely to work. Your body needs time to absorb it, so taking it about an hour beforehand gives you the best chance of success.

Further reading: How long does Viagra take to work & how long does it last?

Eating a heavy, high-fat meal

Viagra absorbs best on an empty stomach. A heavy or high-fat meal can slow digestion and reduce how much of the medication enters your bloodstream.

For the best results, avoid fatty meals and try to wait a couple of hours after eating before taking your ED treatment.

Alcohol

Drinking too much alcohol can make Viagra less effective. Alcohol is a depressant that slows down your nervous system and reduces blood flow to the penis, making it harder to get or maintain an erection even with medication.

For best results, keep alcohol intake low when you plan to take Viagra.

Further reading: Alcohol and Viagra

Psychological factors

ED does not just have physical causes – psychological factors can have a major impact too.
Stress, anxiety, relationship issues, performance pressure, or general worry can all interfere with sexual arousal.

Even if Viagra is physically working to improve blood flow to the penis, psychological barriers can stop you from becoming fully aroused, making it seem like the medication is not working.

Further reading: Is ED psychological or physical?

Underlying health conditions

Certain health conditions can reduce the effectiveness of any erectile dysfunction treatment – not just Viagra.

Conditions such as:

• Diabetes
• High blood pressure
• Heart disease
• High cholesterol
• Obesity
• Hormone imbalances
• Nerve damage

These issues can affect blood flow, nerve function, or hormone levels, all of which are essential for erections.

If these conditions worsen or are not well controlled, ED medication is less likely to work reliably.

You’re simply having an “off day” (it’s normal)

Even when everything is done correctly, you may find that Viagra is not working.

Fatigue, stress, poor sleep, a busy mind, or just not feeling in the mood can all affect sexual performance.

These temporary factors can reduce arousal and make erections harder to achieve, even with ED medication.

An occasional off day does not mean Viagra is not working or that something is wrong. Most men experience this from time to time, and things usually return to normal without needing to change your treatment.

• Try it more than once – Doctors often recommend trying Viagra on up to eight separate occasions before deciding it does not work for you.
• Check your timing – Take Viagra about 1 hour before sex. Taking it too early or too late can reduce its effectiveness.
• Take it on an empty stomach – Avoid large or high-fat meals beforehand, as these can delay absorption and make Viagra less effective.
• Limit alcohol – Alcohol can interfere with erections, reduce arousal, and increase side effects. Low alcohol intake gives the best chance of success.
• Ensure you are sexually aroused – Viagra does not create an erection on its own, sexual stimulation is essential.
• Review your dosage – If 50mg is not effective, your prescriber may recommend the 100mg dose. Do not exceed the prescribed maximum.
• Check for psychological factors – Stress, anxiety, and performance pressure can reduce arousal. Therapy or open communication with your partner can help.
• Look at lifestyle factors – Improving sleep, managing stress, exercising regularly, maintaining a healthy weight, quitting smoking, and eating well all support better erections.
• Consider underlying health conditions – Poorly controlled conditions such as diabetes, high blood pressure, high cholesterol, or hormone imbalances can reduce the effectiveness of any ED medication. Managing these often improves results.
• Test your testosterone levels – Low testosterone can affect how well Viagra works. A doctor can check your hormone levels and advise on treatment if needed.
• Speak to your doctor – A healthcare professional can assess what’s affecting your erections, adjust your treatment plan, or recommend alternatives. Seek urgent help if you experience severe side effects or an erection lasting more than 4 hours (priapism).
• Explore alternative treatments – Other PDE5 inhibitors (Tadalafil, Vardenafil, Avanafil) may work better for some men. Viagra alternatives have good success rates and often work well where Viagra is not working.