Viagra Dosage Strengths: Complete UK Guide

Viagra is available in three MHRA-approved strengths: 25mg, 50mg, and 100mg tablets. Most men start with 50mg, taken 30-60 minutes before sexual activity. Your prescriber may adjust this to 25mg or 100mg based on effectiveness and side effects. EverydayMeds offers both branded Viagra and generic sildenafil options during checkout, allowing you to choose the most suitable treatment for your needs.

  • 25mg - Lower starting dose for men with certain health conditions
  • 50mg - Standard starting dose for most men with erectile dysfunction
  • 100mg - Maximum strength for men who don't respond to lower doses
  • Maximum one tablet per 24-hour period regardless of strength chosen
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Not sure which one? Here's the honest comparison.

Sildenafil
~60 min
~4 hrs
you like to plan ahead
Explore now
Tadalafil (as-needed)Most prescribed
~30 min
up to 36 hrs
you want a whole weekend covered
Explore now
Tadalafil Daily
always active
continuous
you never want to think about timing
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Vardenafil
~15–30 min
~8 hrs
you want the fastest onset
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How ED treatment works in your body.

Increases blood flow

Increases blood flow

When PDE5 is suppressed, blood is able to flow more freely through the body—including to the (you guessed it) penis.

Increase erections

Increase erections

More blood flow to the penis means harder, more satisfying erections once you're sexually stimulated.

How to Choose the Right Viagra Strength

Standard Dosing Guidelines

The typical starting dose for Viagra is 50mg, taken approximately one hour before sexual activity. This strength provides an effective balance between therapeutic benefit and minimal side effects for most men. Your prescriber may recommend starting with 25mg if you're over 65, have liver or kidney problems, or take certain medications that could interact with sildenafil.

When 100mg May Be Recommended

The maximum dose of 100mg is only prescribed when 50mg proves insufficient after several attempts. Your healthcare provider will assess whether increasing the dose is appropriate based on your response to treatment and any side effects experienced. It's important never to exceed 100mg or take more than one tablet within 24 hours, as this increases the risk of serious side effects including dangerous drops in blood pressure.

Adjusting Your Dose Safely

Dose adjustments should only be made following consultation with a qualified prescriber. If you find 50mg too strong and experience bothersome side effects like headaches or dizziness, your doctor may reduce your prescription to 25mg. Conversely, if 50mg doesn't provide adequate improvement in erectile function, they may consider increasing to 100mg after reviewing your medical history and current medications.

Branded vs Generic Options

EverydayMeds provides both Viagra (branded) and sildenafil (generic) in all three strengths. Both contain the same active ingredient and work identically - the choice often comes down to personal preference and cost considerations. Generic sildenafil typically costs significantly less than branded Viagra while providing equivalent therapeutic effects.

Important Safety Considerations

Regardless of the strength prescribed, Viagra should never be taken with nitrate medications used for chest pain, as this combination can cause life-threatening drops in blood pressure. Always inform your prescriber about all medications you're currently taking, including over-the-counter treatments and herbal supplements. Take your prescribed dose 30-60 minutes before planned sexual activity, and avoid fatty meals which may delay the medication's onset of action.

What you need to know about erectile dysfunction

It's one of the most common conditions we treat, and one of the most treatable.

What is Erectile Dysfunction?
ED means finding it hard to get or keep an erection firm enough for sex. It's not unusual to have an off night; the point at which it's worth doing something is when it's happening regularly, or when it's starting to bother you.
How will I feel when I take ED medication?
For most men, nothing feels different day to day. The medication works in the background — when you're sexually aroused, it helps blood flow where it's needed, so erections come more easily and last longer. It doesn't cause arousal on its own. Some men notice mild, short-lived effects like a headache, facial flushing or a stuffy nose, which usually pass as the dose wears off.
Why do I need a prescription for ED medication?
ED treatments are prescription-only medicines in the UK because they aren't suitable for everyone — for example, alongside certain heart conditions or medications like nitrates. That's why we ask you to complete a short online consultation first. A UK-registered prescriber reviews your answers to make sure your chosen treatment is safe and right for you before it's dispensed.
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