Sildenafil vs Tadalafil: Which ED Medication Is Right for You?
Both are FDA-approved, both work well — but the differences matter. Here is what our providers consider when recommending one over the other.
Quick answer: Sildenafil (generic Viagra) is the most affordable option and works well when you can plan 30–60 minutes ahead. Tadalafil 20mg (generic Cialis) gives you up to 36 hours of flexibility. Tadalafil 5mg daily eliminates timing entirely. Both are equally effective — the right choice depends on your lifestyle.
What Are Sildenafil and Tadalafil?
Sildenafil and tadalafil are both PDE5 inhibitors — a class of drugs that increase blood flow to the penis during sexual stimulation. Sildenafil is the active ingredient in Viagra; tadalafil is the active ingredient in Cialis. Both are now available as FDA-approved generics at a fraction of the original brand-name cost.
According to a 2018 meta-analysis published in BJU International, both drugs have comparable efficacy — approximately 70–85% of men with ED experience improved erections with either medication. The meaningful differences are in timing, duration, and side effect profile.
Head-to-Head Comparison
| Factor | Sildenafil 100mg | Tadalafil 20mg | Tadalafil 5mg (Daily) |
|---|---|---|---|
| Generic of | Viagra | Cialis | Cialis (daily) |
| Onset | 30–60 min | 30–45 min | Always active |
| Duration | 4–6 hours | Up to 36 hours | Continuous |
| Dosing | As-needed | As-needed | Once daily |
| Affected by food? | Yes — heavy meals slow onset | No | No |
| Starting price | $35 / 5 doses | $35 / 5 doses | $50 / 30 days |
| Best for | Planned encounters | Spontaneity | No timing at all |
When Providers Recommend Sildenafil
Sildenafil is typically the first recommendation for patients who:
- Are price-sensitive (sildenafil is the most affordable option per dose)
- Can reasonably plan 45–60 minutes ahead of a sexual encounter
- Prefer a shorter duration to minimize time on-drug
- Have had success with sildenafil in the past
One practical note: sildenafil is affected by heavy or high-fat meals. If taken after a large meal, onset can be delayed by 30–60 minutes and the effect may be weaker. Taking it on an empty stomach or after a light meal produces the most consistent results.
When Providers Recommend Tadalafil 20mg
Tadalafil 20mg is the most commonly selected option among Affinity patients. The 36-hour window — which earned it the nickname "the weekend pill" — means one dose covers an entire weekend without needing to time anything. Providers typically recommend it for patients who:
- Want flexibility and spontaneity
- Found sildenafil's 4–6 hour window too short
- Have experienced meal-related timing issues with sildenafil
- Have partners and prefer that neither person feels "on a clock"
When Providers Recommend Daily Tadalafil 5mg
Daily tadalafil 5mg maintains a steady blood level of the drug, eliminating all timing considerations. It is FDA-approved both for erectile dysfunction and for benign prostatic hyperplasia (BPH). Providers typically recommend daily tadalafil for patients who:
- Have frequent sexual activity (more than twice per week)
- Prefer not to plan or time medication at all
- Also have BPH symptoms (urinary frequency, difficulty starting urination)
- Have experienced anxiety around timing with as-needed medications
Daily tadalafil 5mg starts at $0.78/day with the 180-day auto-refill option — less than a cup of coffee, with no timing required. A 30-day auto-refill is $39, or $1.30/day.
Side Effects: What to Know
Both drugs share a common side effect profile. The most frequently reported effects across clinical trials include:
- Headache (10–15% of users)
- Facial flushing (10–12% of users)
- Nasal congestion (4–9% of users)
- Upset stomach (4–7% of users)
Tadalafil uniquely causes back pain and muscle aches in some patients (3–6%), likely related to its longer half-life. Sildenafil is more associated with transient visual disturbances — a blue or blurry tint to vision in roughly 3% of users.
Both drugs are contraindicated with nitrate medications (nitroglycerin, isosorbide). If you take nitrates for chest pain or heart conditions, tell your provider — you cannot take either medication safely.
Common Questions
Can I switch between sildenafil and tadalafil?
Yes. Some patients keep both on hand — sildenafil for planned occasions and tadalafil for weekend use. Discuss this with your Affinity provider; switching or combining requires a provider review.
Does insurance cover sildenafil or tadalafil?
Generic sildenafil and tadalafil are often covered by insurance when prescribed for ED, but coverage varies widely. Affinity Direct provides cash-pay pricing that is frequently cheaper than insurance copays — as-needed ED medication starts at $35 for 5 doses.
Which drug is safer for men with high blood pressure?
Both PDE5 inhibitors can cause a mild blood pressure drop and are generally safe for men with controlled hypertension not taking nitrates. Your Affinity provider will review your health history before prescribing. Men with uncontrolled hypertension, recent cardiac events, or nitrate use require additional evaluation.
What if ED medication does not work?
Non-response or partial response is common on the first few tries. Factors like anxiety, timing, alcohol use, and food can all affect efficacy. Affinity providers offer follow-up consultations at no additional charge to adjust dosing or switch medications.
Ready to find out which is right for you?
Complete a short health intake. A licensed Affinity provider reviews it and prescribes the right medication — typically within 24 hours.
View ED Treatment Options →This article is written and reviewed by the Affinity Direct clinical team for informational purposes. It does not constitute medical advice. All prescriptions require a provider evaluation. Last reviewed: March 2025.