Viagra vs sildenafil: What’s the difference between the...
Reviewed by Dr. Anup Jethwa
Talk early, somewhere calm and away from the bedroom, and say plainly that it isn't your partner's fault.
ED is common; it usually has a physical or stress-related cause, and couples who talk about it openly tend to find treatment easier to start and stick with.
If your erections have changed recently, there's a fair chance you've been carrying the worry on your own.
A lot of men put off saying anything for weeks or months. They hope it sorts itself out, or they feel the subject is somehow tied to how "manly" or desirable they are.
That reaction is understandable.
In a UK survey of 12,490 men published in 2022, 41.5% of men reported some degree of ED, including 29.3% of men aged 18 to 39.
So if this is happening to you, you're not alone. And the person most likely to help you through it is the one sharing your bed.
Before you begin: A little bit about OnlineClinic
OnlineClinic has been operating since 2011 and has treated more than 2.1 million patients.
The pharmacy is registered with the General Pharmaceutical Council (GPhC), our prescribers are registered with the General Medical Council (GMC), and the service is regulated by the Care Quality Commission (CQC).
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Did you know?
An occasional night where things don't work is normal and usually comes down to tiredness, stress, or alcohol. ED is the term doctors use when getting or keeping an erection firm enough for sex is difficult most of the time.
Here's the part many men don't expect. When nothing is said, partners rarely stay neutral. They fill the silence with their own explanations.
Common worries partners describe include:
These worries are natural, and they're almost always wrong.
ED is very rarely about how someone feels about their partner.
The usual causes are physical (blood flow, nerve signals, hormones, some medicines) or linked to stress and anxiety.
Research shows partners feel the effects too.
In the international FEMALES study, 293 female partners of men with ED reported that desire, arousal, and orgasm became less frequent for them after their partner's erection problems began.
Blame makes it harder still.
In a 2021 study published in Sexual Medicine, 79% of women surveyed had been with a partner who lost his erection, and around 1 in 7 had been blamed for it.
Women who were blamed reported lower self-confidence and were more likely to end the relationship.
The takeaway is simple. Silence and blame cost both people something. A calm, honest conversation costs much less.
There's a reassuring side to the research.
Here's the good part
Couples who talk about ED usually feel better for it.
In the Strike Up a Conversation study, men with ED and their partners described similar, positive feelings when they talked openly, and more negative feelings when they didn't.
Partners can also shape whether treatment happens at all.
Follow-up analysis of the FEMALES data found that women's attitudes towards ED and its treatment were linked to whether their partner raised it with a doctor and went on to use treatment.
Sticking with treatment matters too.
When researchers have asked men why they stopped taking ED tablets, partner-related reasons come up regularly, alongside side effects and cost.
Couples-focused studies suggest that when partners are involved from the start, treatment is more likely to fit into the relationship rather than feel like a secret.
There's also a direct link with anxiety.
One difficult night can lead to worry about the next time, and that worry can make an erection harder to get.
Clinicians call this performance anxiety.
Saying it out loud, and hearing that your partner isn't keeping score, takes a lot of that pressure away. We explain the psychological side in more detail in our guide to anxiety-related ED.
When you talk about ED with your partner can matter almost as much as what you say. Couples who've been through this often find these steps help:
Quick tip
If raising it face to face feels too much, a short message can open the door: "Can we have a proper chat later? Nothing bad, there's just something I'd like us to talk about."
Your partner isn't caught off guard, and you've committed to the conversation.
You don't need a perfect speech. Honesty and warmth do most of the work.
It helps to use "I" statements. They describe how you feel rather than sounding like an accusation or a verdict on the relationship.
If you're the one with ED, openers that often work:
Things that tend to make the conversation harder:
If the first conversation is short or awkward, that's fine.
Most couples revisit it several times. The first chat is about opening the door, not solving everything at once.
If your partner has just opened up, or you're the one hoping to talk about it, the first response sets the tone for everything after.
If you're the partner, openers that often help:
Ways partners can show support:
It's also fine to be honest about your own feelings. Saying "I'll be honest, I'd started to worry it was about me" often brings couples closer, because it shows you've both been carrying something.
ED doesn't have to mean intimacy stops. Many couples find that taking the focus off penetrative sex for a while actually helps, because it removes the "will it or won't it" pressure.
Approaches couples find useful:
Here's the good part
Specialist help is easy to find.
The College of Sexual and Relationship Therapists (COSRT), the UK professional body for psychosexual and relationship therapists, has a public register of accredited therapists.
Relate also offers relationship counselling and sex therapy across the UK, for individuals and couples.
Looking at treatment as a team can make it feel less daunting. The main options licensed in the UK are:
Whatever the underlying cause for ED, the first-line treatment for most men is the same class of medication, PDE5 inhibitors, which work by improving blood flow to the penis.
In the UK, four treatment options are licensed for ED: Viagra (sildenafil), Cialis (tadalafil), vardenafil, and Spedra (avanafil).
Apart from the above-mentioned treatments, UK also has a Generic Impotence Trial Pack, which includes 4 tablets of tadalafil 10mg, 4 tablets of vardenafil 10mg, and 4 tablets of sildenafil 10mg. The prices for the same starts from £49.99.
Two are available without a prescription, after a short pharmacist consultation: Viagra Connect (sildenafil) and Cialis Together (tadalafil).
Which one suits you often comes down to how long you want it to last and how you'd like to plan around it, rather than the underlying cause.
| Medicine | Active ingredient | Works in | Lasts upto | Take before sex | Price from* | Good to know |
|---|---|---|---|---|---|---|
| Viagra (branded) / Sildenafil (generic) | Sildenafil | 30 - 60 minutes | Around 4 hours | 30 - 60 minutes | Viagra from £28.99 Sildenafil from £8.99 |
Works best on an empty stomach; a heavy or fatty meal can slow it down |
| Cialis (branded) / Tadalafil (generic) | Tadalafil | Around 30 minutes | Upto 36 hours | At least 30 minutes | Cialis from £42.99 | Nicknamed "the weekend pill" for its long window |
| Cialis Daily | Tadalafil (low dose) | Builds up over a few days of daily use | Continuous, while you keep taking it | Not timed to sex, taken at the same time every day | From £72.99 | Ideal for men having sex more than twice a week |
| Vardenafil | Vardenafil | 15 - 30 minutes | Upto 5 hours | 25 - 60 minutes | Vardenafil from £29.99 | A lower-dose option sometimes suggested alongside other health conditions |
| Spedra | Avanafil | 15 - 30 minutes (often the fastest) | Up to 5 - 6 hours | Around 30 minutes | From £21.99 | A newer option; some men get on with it with fewer side effects |
PDE5 inhibitors should not be taken alongside nitrate medications (commonly prescribed for angina) or recreational nitrates ('poppers'), as the combination can cause a dangerous drop in blood pressure.
Tell your prescriber about all medications you're taking, including any for blood pressure or chest pain, before starting treatment.
Our guides on Viagra vs Sildenafil and Cialis daily vs on-demand walk through the practical differences.
Addressing an underlying cause, whether that's blood pressure, weight, alcohol, stress or a medication switch, often improves things further, alongside or instead of tablets.
We cover the lifestyle part of it in Lifestyle and ED: weight, alcohol, sleep and exercise, and the anxiety part of it in Anxiety-related ED: the psychological side.
Quick tip: Only buy from a regulated source
In February 2026, the MHRA reported seizing nearly 20 million doses of illegal ED medicines between 2021 and 2025, including 4.4 million in 2025 alone.
The regulator warns these products may contain the wrong dose, no active ingredient, or hidden and, harmful substances.
Health Minister Dr Zubir Ahmed said there should be "no shame in talking about erectile dysfunction."
Embarrassment is often what pushes men towards unregulated websites, so talking it through with your partner first can lead to safer choices.
ED is sometimes an early sign of another health condition, which is a good reason to treat the conversation with your partner as the first step rather than the last.
The arteries that supply the penis are narrower than those supplying the heart. If they start to fur up (atherosclerosis), erection problems can show up years before heart symptoms do.
A large systematic review in European Urology found ED is linked to a higher risk of heart disease, stroke, and death from any cause.
Other common causes include:
It's worth booking a GP appointment if:
Did you know?
If you still get erections at other times, such as on waking or on your own, but not with a partner, the cause is more likely to be linked to stress or anxiety.
Clinicians use this pattern to help decide which treatment, or which mix of treatments, is likely to help most.
Important safety point: Don't take sildenafil, tadalafil, or similar tablets if you use nitrates, often prescribed for chest pain (for example, GTN spray or isosorbide tablets).
The combination can cause a dangerous drop in blood pressure. If you get chest pain during or after sex, call 999.
Many couples find it reassuring to go to appointments together.
A doctor will usually ask about lifestyle and relationships, check blood pressure, and may arrange blood tests for blood sugar, cholesterol, and testosterone. More detail is in our guide on when to see a doctor about ED.
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Disclaimer
ED medicines are prescription-only or pharmacy medicines. Decisions about treatment are made by a GMC-registered prescriber or pharmacist based on your medical history. This guide is for general information and isn't a substitute for professional medical advice.
Reviewed by Dr. Anup Jethwa
Reviewed by Dr. Anup Jethwa
Reviewed by Dr. Anup Jethwa
Reviewed by Dr. Anup Jethwa
Reviewed by Dr. Anup Jethwa
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