Men's Sexual Health
Tadalafil (Cialis): How It Works, Dosing, and Safety
Medically reviewed by HealthRX.com Medical Team · Last reviewed
What is tadalafil and how does it work?
Tadalafil is a PDE5 inhibitor that improves blood flow to the penis during arousal. Its defining feature is a long duration, up to 36 hours, which is why it is sometimes called the weekend option. It needs sexual stimulation to work.
Peak levels are reached at a median of about 2 hours, and the medicine has a long half-life of about 17.5 hours, which explains the extended window. [2]
How is tadalafil dosed?
Tadalafil has two dosing strategies. As-needed dosing starts at 10 mg before activity, ranging from 5 to 20 mg. Low daily dosing starts at 2.5 mg and can rise to 5 mg once a day, which allows spontaneity without timing a dose. It can be taken with or without food.
| Strategy | Dose | Best for |
|---|---|---|
| As needed | 5 to 20 mg before activity | Occasional use |
| Daily | 2.5 to 5 mg once daily | Spontaneity; also helps BPH |
Does tadalafil treat prostate symptoms?
Yes. Tadalafil is FDA approved for erectile dysfunction, for the signs and symptoms of benign prostatic hyperplasia (BPH), and for both together. The BPH dose is 5 mg once daily, which can address urinary symptoms and erectile function at the same time.
This dual use makes daily tadalafil attractive for men who have both ED and an enlarged prostate. [3]
Is tadalafil safe, and what are the side effects?
Tadalafil is generally well tolerated, but it must never be combined with nitrates, which can cause a dangerous drop in blood pressure. Use caution with alpha-blockers. Common side effects include headache, indigestion, back pain and muscle aches, the last two being more typical of tadalafil.
- Never take with nitrates or poppers; this is an absolute contraindication. [2]
- Use caution with alpha-blockers and other blood pressure medicines. [2]
- Common: headache, indigestion, flushing, nasal congestion, back pain, muscle ache.
- Seek urgent care for an erection over four hours or sudden vision or hearing loss.
How does Tadalafil compare with other peptides?
| Tadalafil | Sildenafil | |
|---|---|---|
| Duration | Up to 36 hours | Several hours |
| Dosing | As needed or daily | On demand only |
| Food effect | Little | High-fat meal delays it |
| Other use | Also treats BPH | ED only |
Frequently asked questions
How long does tadalafil last?
Tadalafil can support erectile function for up to 36 hours, much longer than sildenafil. This long window is why it is sometimes called the weekend option and why some men prefer it for spontaneity.
Can I take tadalafil every day?
Yes. A low daily dose of 2.5 to 5 mg is an approved option that allows spontaneity without timing a dose before activity. Daily tadalafil at 5 mg also helps benign prostatic hyperplasia.
Can I take tadalafil with food?
Yes. Unlike sildenafil, tadalafil is not meaningfully affected by food, so a meal, including a fatty one, does not require a timing change.
What should I never combine with tadalafil?
Never combine tadalafil with nitrate heart medicines such as nitroglycerin, or with recreational poppers. The combination can cause a dangerous, potentially life-threatening drop in blood pressure. Tell your prescriber all your medicines.
Does tadalafil help an enlarged prostate?
Yes. Tadalafil is FDA approved for the signs and symptoms of benign prostatic hyperplasia at 5 mg once daily, and can treat ED and BPH together.
Citations
- CIALIS (tadalafil) tablets, FDA Prescribing Information (DailyMed).
- Tadalafil tablets (ED, BPH, ED/BPH), FDA Prescribing Information (DailyMed).
- Corbin JD. Mechanisms of action of PDE5 inhibition in erectile dysfunction. Int J Impot Res. 2004;16(Suppl 1):S4-S7.
- Dhaliwal A, Gupta M. PDE5 Inhibitors. StatPearls. NCBI Bookshelf; updated 2023.
This guide is educational and is not a substitute for individualized medical advice. Tadalafil is prescription-only and requires evaluation by a licensed provider.