Viagra vs Cialis vs Sildenafil : Your Complete Guide to Choosing the Right ED Treatment

Erectile dysfunction affects over 4.3 million men across the UK, yet many remain uncertain about which treatment option suits them best. With multiple medications available — from branded Viagra and Cialis to generic sildenafil and even over-the-counter Viagra Connect — navigating your choices can feel overwhelming. Understanding the differences between these treatments empowers you to make informed decisions about your sexual health and wellbeing.

At Happy Pharmacy, our regulated online consultation service provides personalised support to help you find the most effective, safe ED treatment for your individual needs. This comprehensive guide breaks down everything you need to know about Viagra, Cialis, sildenafil, and other erectile dysfunction medications available in the UK.

---

Understanding Erectile Dysfunction: You're Not Alone

Before exploring treatment options, it's important to recognise that erectile dysfunction (ED) is incredibly common. Recent UK studies show that approximately 41.5% of men report experiencing ED, with prevalence increasing with age. However, ED doesn't only affect older men — studies reveal that 58.2% of UK men of all ages have experienced difficulties achieving or maintaining erections during sexual encounters.

Common causes of ED include:

• Cardiovascular disease

• Diabetes

• High blood pressure

• Obesity

• Psychological factors

• Lifestyle choices (e.g. smoking, excessive alcohol)

Often, ED serves as an early warning sign for other health conditions, making it crucial to address both the symptoms and any underlying causes.

The good news? Effective treatments are readily available, and seeking help through a confidential online consultation with Happy Pharmacy means you can access safe, regulated medication without the embarrassment some men feel when discussing ED face-to-face.

---

The Foundation: How ED Medications Work

All the main ED treatments — Viagra, Cialis, sildenafil, and tadalafil — belong to a class of medications called phosphodiesterase type 5 (PDE5) inhibitors. These medications work by relaxing the smooth muscles in blood vessels supplying the penis, thereby increasing blood flow to aid erections.

Crucially, these medications require sexual stimulation to work. They don't cause spontaneous erections or increase sexual desire. Rather, they facilitate your body's natural erectile response when you're sexually aroused.

According to NHS and NICE guidelines, PDE5 inhibitors are the recommended first-line treatment for erectile dysfunction, with proven safety and effectiveness when used appropriately under medical supervision.

---

Viagra vs Sildenafil: Understanding Brand vs Generic

What's the Difference?

Many men wonder about the difference between Viagra and sildenafil. The answer is straightforward: sildenafil is the active ingredient in Viagra. When people refer to "Viagra," they're talking about the branded version manufactured by Pfizer, whilst sildenafil refers to the generic version containing exactly the same active ingredient.

Both medications work identically because they contain the same chemical compound. The primary differences lie in cost and branding — generic sildenafil is considerably cheaper, with prices starting from as little as 50p per tablet compared to around £5 for branded Viagra.

---

How Viagra/Sildenafil Works

• Typically begins working within 30 to 60 minutes after taking a tablet

• Effects last approximately 4 to 6 hours

• Works best on an empty stomach

• Alcohol can reduce effectiveness

---

Dosages Available

Sildenafil/Viagra comes in three strengths:

• 25mg – Lower dose for those experiencing side effects at higher doses

• 50mg – Standard starting dose for most men

• 100mg – Higher dose if 50mg proves insufficient

Clinical trials demonstrate that the 50mg dose works effectively for ~74% of men, whilst the 100mg dose increases effectiveness to ~82%.

---

Viagra Connect: The Over-the-Counter Option

Since 2018, Viagra Connect has been available over-the-counter at UK pharmacies without requiring a prescription. This 50mg formulation contains sildenafil and works exactly like prescription Viagra, but can be purchased after a brief consultation with a pharmacist.

---

Cialis vs Tadalafil: The "Weekend Pill"

What's the Difference?

Just like Viagra and sildenafil, Cialis is the brand name whilst tadalafil is the generic equivalent. Cialis was developed by Eli Lilly and approved in 2002. Since the patent expired in November 2017, generic tadalafil has become available at significantly lower cost whilst maintaining identical effectiveness.

---

How Cialis/Tadalafil Works

• Remains effective for up to 36 hours — earning it the nickname "the weekend pill"

• Takes between 30 minutes to 2 hours to start working

• Food does not affect absorption

• Allows for more spontaneity without precise timing

---

Dosages and Daily Options

On-Demand (before sex):

• 10mg – Standard starting dose

• 20mg – Higher dose if 10mg insufficient

Daily Low-Dose:

• 2.5mg or 5mg – Continuous readiness, ideal for frequent sexual activity or BPH

---

Comparing Effectiveness: Viagra vs Cialis

Clinical Trial Results

• Viagra/Sildenafil: ~84% effectiveness

• Cialis/Tadalafil: ~81% effectiveness

Duration Comparison

---

Cialis Together: A New Approach

Cialis Together focuses on communication and shared decision-making. It recognises that ED affects relationships, not just individuals, and encourages couples to discuss treatment options together — strengthening trust and improving treatment outcomes.

---

Side Effects: What to Expect

Common Side Effects (Both):

• Headaches

• Facial flushing

• Indigestion

• Nasal congestion

• Dizziness

Viagra-specific:

• Visual changes (blue vision, light sensitivity) — ~3% of users

Cialis-specific:

• Back pain

• Muscle aches

• Upper respiratory infections

Because Cialis lasts longer, side effects may persist slightly longer too.

---

Safety Considerations and Contraindications

Do not use PDE5 inhibitors if:

• You take nitrates or “poppers” — dangerous blood pressure drops possible

NHS SLS Criteria:

• Diabetes mellitus

• Severe distress due to ED

• Multiple sclerosis

• Parkinson's disease

• Prostate cancer/prostatectomy

• Spinal cord injury

• Severe pelvic injury

For those who don’t qualify, private prescriptions from regulated pharmacies like Happy Pharmacy offer safe, affordable alternatives.

---

Choosing Between Viagra and Cialis: Personal Factors

Consider Viagra/Sildenafil If You:

• Prefer quick onset and short duration

• Have predictable sexual activity

• Want a lower-cost option

• Experience ED occasionally

• Prefer taking medication only when needed

Consider Cialis/Tadalafil If You:

• Value spontaneity

• Have unpredictable or frequent sex

• Prefer longer-lasting effects

• Often eat large meals before intimacy

• Want a daily option

• Have BPH symptoms

Consider Cialis Daily If You:

• Have sex 3+ times a week

• Don’t want to plan ahead

• Want a more “natural” feel

• Are comfortable taking daily medication

---

Cost Considerations: Getting Value

Generic Options:

• Sildenafil: ~£0.50–£2/tablet

• Tadalafil: ~£1–£3/tablet

Branded:

• Viagra: ~£5/tablet

• Cialis: ~£4–£8/tablet

OTC:

• Viagra Connect 50mg: ~£23 for 4 tablets

---

The Role of Lifestyle Changes

Evidence-Based Modifications:

• Exercise: Improves blood flow and ED outcomes

• Healthy diet: Supports vascular health

• Weight loss: Reduces ED risk by ~50%

• Quit smoking: Improves circulation

• Moderate alcohol: Enhances performance

• Manage stress: Addresses psychological causes

---

Starting Treatment: The Happy Pharmacy Process

1. Complete an Online Consultation – quick, confidential questionnaire

2. Clinical Review – UK professionals assess suitability

3. Personalised Treatment – tailored recommendations

4. Discreet Delivery – unmarked packaging to your door

5. Ongoing Support – adjustments and guidance as needed

---

When to Seek Further Medical Advice

Seek medical help if:

• ED appears suddenly or worsens quickly

• Chest pain or cardiac symptoms occur

• New urinary symptoms or pain develop

• ED persists despite treatment

• You suspect underlying conditions

---

Breaking the Silence: Overcoming Stigma

Despite affecting millions, only ~1/3 of men seek help.
Barriers include:

• Embarrassment

• Myths about ageing

• Fear of judgement

• Self-esteem concerns

• Lack of awareness

• Limited access to care

Treatment Improves:

• Sexual satisfaction

• Relationship quality

• Self-esteem

• Early detection of disease

• Overall wellbeing

---

Comparing All Options: Quick Reference Guide

---

Frequently Asked Questions

Can I switch between Viagra and Cialis?
Yes — but never take both on the same day.

How quickly do they work?
Viagra: 30–60 mins. Cialis: 30 mins – 2 hrs.

What if the first dose doesn’t work?
Try at least 4–8 times at the highest tolerated dose before concluding ineffectiveness.

Can I take ED medication daily?
Only Cialis Daily is designed for daily use.

Are generics as effective as branded?
Yes — they’re chemically identical.

Will ED medication make me larger?
No — they improve erections but don’t increase size or libido.

---

Your Next Steps

Erectile dysfunction is treatable. Whether occasional or persistent, Happy Pharmacy’s regulated consultation offers confidential, tailored access to treatment following NHS and NICE guidance.

Take Control of Your Sexual Health Today:

• Personalised treatment recommendations

• Safe, regulated medication

• Expert clinical support

• Discreet home delivery

• Ongoing care

 

Blog medically reviewed by : Nigel Howard, GPhC Registered Prescriber, 10 October 2025

---

References

1. NHS. Erectile dysfunction (impotence). 

2. NHS. How and where to get sildenafil. 

3. Viagra Connect Official Site. Over the Counter ED Treatment. 

4. King's College London. The global prevalence of erectile dysfunction. August 2019.