Both are effective. Both are PDE5 inhibitors. The right choice depends on how often you are sexually active, whether you also have urinary symptoms, and whether you prefer as-needed or continuous coverage. Here is the side-by-side.
| Factor | Sildenafil | Tadalafil |
|---|---|---|
| Brand name | Viagra | Cialis |
| Half-life | ~4 hours | ~17.5 hours |
| Duration of effect | 4–6 hours | Up to 36 hours |
| Onset (oral) | 30–60 minutes | 30–60 minutes |
| Sublingual troche | Compounded alternative dosage form ($89/month), not FDA-approved; onset data for compounded troches are limited. Prepared by a licensed 503A compounding pharmacy (for example Hallandale Pharmacy or Valiant Compounding Pharmacy), named on your prescription label. | |
| Affected by food | Yes (fatty meals delay oral) | No |
| Daily dosing approved | No | Yes (2.5–5 mg) |
| Also treats BPH | No | Yes (5 mg daily) |
| Common side effects | Headache, flushing, nasal congestion, visual color changes | Headache, back pain, muscle aches, nasal congestion |
| YourMD starting price | $59/month (generic tablet) | $59/month (generic tablet) |
No. Never combine PDE5 inhibitors. If switching from one to the other, wait at least 24 hours (sildenafil to tadalafil) or 48 hours (tadalafil to sildenafil) for the first drug to clear.
Make sure your heart is healthy enough for sexual activity. Seek emergency care for chest pain or an erection lasting more than 4 hours. If you have sudden vision or hearing loss, stop the medication and seek urgent care.
Not sure? Your YourMD physician will recommend during your free screening.
Medical disclaimer: Educational content, not medical advice. Page medically reviewed by Teja V. Surapaneni, MD, MS (NV, WA, OR, WI). Last reviewed: April 17, 2026