Tadalafil vs sildenafil:
the sprinter and the marathoner
The short answer
Tadalafil and sildenafil are both PDE5 inhibitors that improve blood flow so arousal can produce an erection. The practical difference is time: sildenafil generally works for about 4–6 hours and is slowed by fatty food, while tadalafil can stay active up to roughly 36 hours and can be taken as a low daily dose. Tadalafil is more associated with back and muscle aches; sildenafil with flushing and temporary blue-tinged vision. Neither is "stronger" in any universal sense, neither works without arousal, both are prescription only, and neither is safe with nitrates.
| Tadalafil | Sildenafil | |
|---|---|---|
| Also sold as | Cialis (brand) | Viagra (brand) |
| Typical as-needed doses | 10mg or 20mg | 25mg, 50mg or 100mg |
| Daily low-dose option | Yes — 2.5mg or 5mg once daily | Not usually prescribed daily |
| Onset (varies by person) | Often around 30–60 minutes | Often around 30–60 minutes |
| How long it lasts | Up to about 36 hours | Roughly 4–6 hours for most men |
| Effect of a fatty meal | Little to no effect | Can noticeably delay onset |
| Most common complaints | Headache, back and muscle aches, indigestion | Headache, flushing, blue-tinged vision |
| Also treats | Enlarged prostate (BPH) symptoms | Pulmonary arterial hypertension (different dosing) |
| Safe with nitrates? | No — never | No — never |
Which one should you ask about?
It usually comes down to how you actually live. If sex tends to happen on weekends and you would rather not think about timing, the long window of tadalafil (or a low daily dose) suits you. If you want to take something deliberately before a planned evening and prefer a shorter tail of side effects, sildenafil is the classic pick. Cost, other medications, blood pressure and prostate symptoms all move the decision, which is exactly why a licensed provider makes it rather than a website.
Why would a prescription combine both?
Some providers prescribe a compounded combination — such as our tadalafil 20mg / sildenafil 70mg rapid-dissolve tablet — to pair a faster-hitting active with a longer-lasting one in a single sublingual dose. Compounded combinations are prepared by licensed compounding pharmacies and are not FDA-approved as combination products; the FDA does not review compounded drugs for safety, effectiveness or quality. Never combine two PDE5 inhibitors on your own — dose stacking raises the risk of dangerously low blood pressure.
Safety rules that apply to both
- Never with nitrates (nitroglycerin, isosorbide) or recreational "poppers" (amyl nitrite), and never with riociguat.
- Never more than one dose in 24 hours unless your provider says otherwise.
- Seek emergency care for an erection lasting more than four hours, chest pain during sex, or sudden loss of vision or hearing.
- Tell your provider about alpha blockers, blood pressure medication, heart disease, liver or kidney disease, and every supplement you take.
Full details live on our Important Safety Information page.
Let a provider settle it
Three-minute intake, licensed US providers, discreet shipping from licensed pharmacies. Prescription only, subject to approval.
Start NowThis page is general health information, not medical advice, and does not replace a consultation with a licensed clinician.