# Viagra vs Cialis: Which One Should You Try First?

> Sildenafil and tadalafil are similarly effective. The decision comes down to how long you want the effect to last, how much food matters to you, and which side effects you would rather avoid.

- **Source:** ED Treatment Guides (https://www.edtreatmentguides.com/compare/viagra-vs-cialis)
- **Last updated:** 2025-11-18
- **Type:** comparison
- **Compares:** Viagra (sildenafil) vs Cialis (tadalafil)

## Key points

- Effectiveness is essentially equivalent: both help roughly 60–70% of men.
- The real difference is duration — 4–6 hours versus up to 36.
- Sildenafil is affected by fatty meals; tadalafil is not.
- Tadalafil is the only one with a licensed daily dose, and the only one that also treats prostate symptoms.
- Both are cheap as generics. Brand-name pricing is not justified by any clinical difference.

## Viagra (sildenafil) vs Cialis (tadalafil)

|  | Viagra (sildenafil) | Cialis (tadalafil) |
| --- | --- | --- |
| Onset | 30–60 minutes | 30 minutes – 2 hours |
| Useful window | 4–6 hours | Up to 36 hours |
| Half-life | About 4 hours | About 17.5 hours |
| Effect of food | Fatty meals delay it significantly | Minimal |
| Daily dosing option | No | Yes — 2.5 or 5 mg |
| Also treats prostate symptoms | No | Yes, at the daily dose |
| Characteristic side effect | Blue-tinged vision | Back and muscle ache |
| Wait before nitrates | 24 hours | 48 hours |
| Typical generic cost | $5–$40/month | $10–$50/month |
| Response rate | Roughly 60–70% | Roughly 60–70% |

## Verdict

If sex is planned and infrequent, or cost is the deciding factor, start with sildenafil. If you want to stop planning around a tablet, if you also have prostate symptoms, or if you eat a proper meal before sex, tadalafil is the better fit. Neither is more effective than the other — and if the first one disappoints, trying the second is standard practice, not a failure.

## The difference that actually matters

Both drugs block the same enzyme by the same mechanism. What separates them is pharmacokinetics: tadalafil's half-life is roughly four times longer, which changes the experience of using it far more than it changes the erection itself.

With sildenafil, you take a tablet, wait, and have a window. With tadalafil taken on Friday evening, that window covers most of the weekend. With daily low-dose tadalafil, there is no window — the drug is simply always present.

> **Ask the right question**
>
> 'Which is stronger?' is the wrong question — they are comparable. 'How do I want sex to fit into my life?' is the right one, and it gives you a clear answer.

## Choose sildenafil if

- Cost is the deciding factor — it is usually the cheapest option available.
- You have sex once a week or less, and generally know in advance.
- You would rather the drug clear your system quickly.
- You have cardiac disease and the shorter nitrate window matters to you.
- You have had back or muscle ache on tadalafil.

## Choose tadalafil if

- You dislike planning sex around a tablet — this is the most common reason men prefer it.
- You have sex more than twice a week, which makes the daily dose attractive.
- You also have urinary symptoms from an enlarged prostate.
- You often eat a substantial meal before sex.
- You have had visual side effects on sildenafil.
- Performance anxiety is significant, and separating the tablet from the sexual event would help.

> **One caveat for cardiac patients**
>
> Tadalafil's long half-life means a **48-hour** wait before nitrates can be given safely, versus 24 hours for sildenafil. If you have angina or a significant chance of needing emergency nitrate treatment, discuss that trade-off explicitly with your clinician.

## Switching between them

If the first choice does not work well after a genuine trial — four to eight attempts at the maximum tolerated dose, taken correctly — switching to the other is standard and sensible. Some men respond considerably better to one than the other for reasons that are not well understood.

Do not take them on the same day, and do not overlap the end of one with the start of the other without your prescriber's guidance. Give tadalafil a couple of days to clear before starting a different regimen.

## Frequently asked questions

### Which works better, Viagra or Cialis?

Neither. Response rates are comparable. Preference studies favour tadalafil, and the reason given is almost always the longer window rather than a firmer erection.

### Can I take both?

No. Do not combine PDE5 inhibitors. It raises the risk of low blood pressure and priapism without improving the result.

### Which is cheaper?

Generic sildenafil is usually slightly cheaper, but both are inexpensive as generics. Prices vary considerably between pharmacies.

### Which has fewer side effects?

They have similar overall rates but different characteristic effects — visual disturbance with sildenafil, back and muscle ache with tadalafil. Avanafil is the most selective and often the best tolerated.

## Sources

- U.S. Food and Drug Administration. [Drugs@FDA — approved drug products and prescribing information](https://www.accessdata.fda.gov/scripts/cder/daf/)
- American Urological Association. [Erectile Dysfunction: AUA Guideline](https://www.auanet.org/guidelines-and-quality/guidelines/erectile-dysfunction-(ed)-guideline) (2018)
- MedlinePlus (National Library of Medicine). [Drugs, Herbs and Supplements](https://medlineplus.gov/druginformation.html)

## Related pages

- [Sildenafil (Viagra): How It Works, Dosing, Cost and Side Effects](https://www.edtreatmentguides.com/treatments/sildenafil)
- [Tadalafil (Cialis): The 36-Hour Option, Daily Dosing and Costs](https://www.edtreatmentguides.com/treatments/tadalafil)
- [Daily vs On-Demand Tadalafil: Which Regimen Fits Your Life?](https://www.edtreatmentguides.com/compare/daily-vs-on-demand)
- [ED Medication Dosage Guide](https://www.edtreatmentguides.com/guides/dosage-guide)

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_This page is general health information, not medical advice. It cannot account for your own history, medications or risk factors. Talk to a licensed clinician before starting, stopping or changing any treatment._

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