Sildenafil 50mg tablets box of 30 beside a blister strip of blue tablets

Sildenafil

How it works

Blocks PDE5 to increase blood flow when aroused

Effect

Works in 30-60 minutes, lasts 4-6 hours. 82% success rate

From

£7.99

for 4 tablets

This treatment option is subject to a consultation followed by clinical review.

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What is Sildenafil?

Sildenafil is the active ingredient in Viagra — the world’s first oral ED medication. When Pfizer’s patent expired in 2013, other manufacturers could produce generic versions, making this life-changing treatment much more affordable.

Generic Sildenafil contains exactly the same active ingredient, in the same doses, with the same efficacy as branded Viagra — just without the premium price tag. It’s manufactured to the same strict UK quality standards.

Sildenafil works by increasing blood flow to the penis when you’re sexually aroused, helping you achieve and maintain an erection. It won’t cause an erection on its own — you still need sexual stimulation.

How effective is Sildenafil?

Sildenafil has over 25 years of clinical evidence and is the most widely used ED treatment in the world. Here’s what the data shows:

  • 82% of men report improved erections with Sildenafil, making it one of the most effective treatments available for erectile dysfunction.
  • Works in as little as 30 minutes and the effects last 4-6 hours, giving you a flexible window for sexual activity.
  • Available in 25mg, 50mg, and 100mg doses, allowing your treatment to be tailored to your individual needs and response.

Many men find Sildenafil works better after a few uses, once they’re more comfortable and relaxed. If 50mg isn’t effective, your doctor may recommend adjusting the dose.

Slim man and a heavier man standing back to back, showing different body shapes

How does Sildenafil work?

Sildenafil is a PDE5 inhibitor — it works with your body’s natural arousal process to help you get and maintain an erection.

It doesn’t create arousal or cause automatic erections. Instead, it removes the barrier that’s preventing the natural process from working properly. Here’s how:

01

Arousal triggers the process: When you’re sexually stimulated, your brain sends signals that release nitric oxide in the penis. This starts the natural process of getting an erection by relaxing blood vessel walls.

02

Sildenafil blocks PDE5: Normally, an enzyme called PDE5 breaks down the chemicals that cause erections. Sildenafil blocks this enzyme, allowing those chemicals to build up and work more effectively.

03

Increased blood flow: With PDE5 blocked, blood vessels in the penis relax and widen. More blood flows in and stays in, resulting in a firmer, longer-lasting erection when you’re aroused.

04

Same as Viagra, fraction of the price: Generic Sildenafil contains exactly the same active ingredient as branded Viagra, manufactured to the same UK quality standards. The only difference is the name on the box — and the price you pay.

05

Safe for long-term use: Sildenafil has been used safely by millions of men for over 25 years. There’s no evidence of tolerance (needing higher doses over time) or dependency. Many men use it successfully for decades.

Smiling woman with curly hair in a turquoise vest top exercising outdoors in the sunshine
Smiling woman with curly hair in a turquoise vest top exercising outdoors in the sunshine

Who is eligible for Sildenafil?

Sildenafil is a prescription treatment for men experiencing erectile dysfunction. If you have difficulty getting or keeping erections, it may be the right option for you.

Here’s what’s involved:

  • Eligibility: You must be a man aged 18 or over experiencing difficulty getting or maintaining erections.
  • As-needed treatment: Sildenafil is taken when you need it — about 30-60 minutes before sexual activity. No need to take it every day.
  • Dose options: Available in 25mg, 50mg, and 100mg. Most men start on 50mg and adjust based on effectiveness and tolerability.
  • Assessment process: You’ll complete a quick, confidential online questionnaire about your health and symptoms.
  • Clinical review: A Trimu clinician will review your answers and medical history to recommend the most appropriate dose for you.

Who shouldn’t use Sildenafil?

Sildenafil isn’t suitable for everyone. It should not be used if you:

  • Take nitrate medications (e.g., GTN spray, isosorbide) or amyl nitrite (“poppers”) — this combination can cause a dangerous drop in blood pressure.
  • Take riociguat (for pulmonary hypertension).
  • Have severe heart or liver problems.
  • Have had a recent stroke or heart attack.
  • Have very low blood pressure.
  • Have rare eye conditions (NAION, retinitis pigmentosa).
  • Are allergic to sildenafil or any of its ingredients.

Instructions

How to take Sildenafil

Take Sildenafil as needed, about 30-60 minutes before you plan to have sex. Swallow the tablet whole with water. It works best on an empty stomach or after a light meal — fatty foods can delay absorption. Never take more than one dose in 24 hours, and limit alcohol to 1-2 drinks for best results.

Step-by-step Instructions

Step 1

Take 30-60 minutes before

  • Take your prescribed dose about 30-60 minutes before you plan to have sex. It can take up to 2 hours to work for some men.
  • Swallow the tablet whole with a glass of water. Do not crush or chew.
  • For fastest results, take on an empty stomach or after a light meal. Fatty foods can significantly delay how quickly it starts working.

Step 2

Limit alcohol and heavy food

  • Alcohol can reduce Sildenafil’s effectiveness and worsen side effects like headache and dizziness. Keep it to 1-2 drinks maximum.
  • Heavy, fatty meals can delay absorption significantly. If you’ve eaten a large meal, it may take longer to feel the effects.
  • Remember, you still need to be sexually aroused for Sildenafil to work — it doesn’t create desire or automatic erections.

Step 3

During the 4-6 hour window

  • The effects last 4-6 hours — this doesn’t mean you’ll have an erection the whole time, just that you’ll find it easier to get one when aroused.
  • Erections will come and go naturally within this window based on sexual stimulation — just as they would normally.
  • Sildenafil works best when you’re relaxed. Give it a few tries — many men find it works better once they’re more comfortable with it.

Step 4

Important safety notes

  • Never take more than one dose (maximum 100mg) in any 24-hour period. If one dose doesn’t work, don’t take another.
  • Seek immediate medical attention if you experience an erection lasting more than 4 hours (priapism), sudden vision loss, or chest pain.
  • Store tablets at room temperature, away from moisture and direct sunlight. Keep out of reach of children.

FAQs

Things you should know about Sildenafil

Sildenafil typically starts working within 30-60 minutes, though it can take up to 2 hours for some men. For fastest results, take it on an empty stomach. Fatty foods can significantly delay absorption. Once it starts working, the effects last 4-6 hours — though this doesn’t mean you’ll have an erection the whole time, just that you’ll find it easier to get one when aroused.

Don’t give up after one try. Many men find Sildenafil works better after a few attempts, once they’re more comfortable with it. If 50mg isn’t effective, your doctor may recommend trying 100mg. It’s also important to ensure you’re following the guidelines — taking it on an empty stomach, avoiding excess alcohol, and being sexually aroused. If it still doesn’t work, alternatives like Tadalafil (Cialis) work differently and may suit you better.

No. Sildenafil doesn’t cause automatic erections — it only works when you’re sexually aroused. It helps the natural erection process work more effectively by increasing blood flow to the penis. You still need mental or physical stimulation. This is actually a benefit: it means you won’t have an unwanted erection at inappropriate times.

Yes, Sildenafil can be taken daily if needed, though most men use it on-demand. You shouldn’t take more than one dose (maximum 100mg) in any 24-hour period. If you want a daily option that allows for more spontaneity, Tadalafil 5mg (daily Cialis) might be a better choice — it’s specifically designed for daily use and provides round-the-clock readiness.

Yes, Sildenafil has been used safely by millions of men for over 25 years. There’s no evidence of tolerance (needing higher doses over time) or dependency. Many men use it successfully for decades. However, it’s important to have regular check-ups and let your doctor know about any health changes, as some conditions can develop that make ED medications less suitable.

Both are PDE5 inhibitors that work similarly, but Tadalafil (Cialis) lasts much longer — up to 36 hours vs 4-6 hours for Sildenafil. This makes Tadalafil better for spontaneity (“the weekend pill”). Tadalafil is also less affected by food. However, Sildenafil may work faster and some men find it more effective. Many men try both to see which suits them better.

Sildenafil 50mg is available over the counter at pharmacies under the brand name Viagra Connect (without a prescription). However, generic Sildenafil and higher doses (100mg) still require a prescription. Getting a prescription through our online service is often more convenient and cost-effective than buying Viagra Connect from a pharmacy.

Most side effects are mild and temporary. Common effects (1 in 10) include headache, facial flushing, indigestion, nasal congestion, and dizziness — these occur because Sildenafil dilates blood vessels throughout the body and usually pass within a few hours. Uncommon effects (1 in 100) include blue-tinged or blurred vision, muscle aches, and nausea. Rare but serious effects requiring immediate medical attention include priapism (erection lasting 4+ hours), sudden vision loss, sudden hearing loss, and chest pain.

Erectile Dysfunction Treatments

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  • Generic Sildenafil

    The active ingredient in Viagra.

    Sildenafil 50mg tablets box of 30 with a blister strip of blue tablets

    From

    £7.99

    /month

    Learn More Buy Now

  • Generic Tadalafil

    The active ingredient in Cialis.

    Tadalafil 5mg film-coated tablets box with two blister strips of white tablets

    From

    £11.99

    /month

    Learn More Buy Now

  • Viagra Connect

    The original Viagra brand.

    Viagra Connect (sildenafil) 50mg film-coated tablets box with a blister of four blue tablets

    From

    £28.99

    /month

    Learn More Buy Now

  • Cialis Together

    The original Cialis brand. 

    Cialis Together (tadalafil) 10mg tablets box of four with blister strip of yellow tablets

    From

    £45.99

    /month

    Learn More Buy Now

Why you can trust Trimu

Regulated care from a registered UK pharmacy

Safe, discreet treatment — reviewed by qualified clinicians and dispensed by our own UK-registered pharmacy.

Registered UK pharmacy

Dispensed by a GPhC-registered UK pharmacy (premises 1037748).

Reviewed by registered clinicians

GMC-registered doctors and GPhC-registered pharmacists check every case before any treatment is approved.

Discreet, ongoing support

Free, discreet delivery and clinical support throughout your treatment.

Our mission

Trimu began with a simple belief: getting safe, effective treatment shouldn’t be expensive, complicated, or embarrassing. We pair UK-registered clinicians with our own regulated pharmacy to offer honest advice, fair prices, and genuinely discreet care — so you can get on with feeling better.