Over 1,000,000+ Roman members

Genuine Tadalafil Prescribed Online

Get $15 off your first order

Hear back within 24 hours

Free shipping, always

Save up to 95% with generic medication

Skip the pharmacy lines

How Cialis® works

The Cialis® rundown

Stay ready

There are two ways you can take Cialis®. You can take it as a simple, once-a-day pill at a smaller dose so you’ll always be ready to perform when the mood is right. Or you can take Cialis® as needed at a higher dose, 30 minutes before you plan to have sex. 

Stronger erections

Cialis® blocks an enzyme called PDE5, which makes it easier for blood to flow to the penis for a stronger, longer lasting erection.

Long-lasting results

Cialis® stays in the body for 24-36 hours. During that time a person has an easier time getting and maintaining an erection. It doesn’t cause immediate arousal, so you’ll only get erect when you’re in the mood. That means when the time is right, turn up the romance.

What safety information should I know before taking Cialis®?

Do not take Cialis® if you take any medicines called nitrates, often prescribed for chest pain, or guanylate cyclase stimulators like Adempas (riociguat) as this can result in a sudden, dangerous drop in blood pressure. Learn more

What is Cialis®?

Cialis® is a drug that is used to treat erectile dysfunction (ED). It comes in four doses, 2.5 mg, 5 mg, 10 mg, and 20 mg. Cialis® can be taken as needed in any of the four doses. The 2.5 mg and 5 mg doses are also approved for daily use for ED.

To understand how Cialis® works to treat ED, it’s important to first understand the basics of how erections work. Blood flow plays a key role in getting an erection and the penis needs to be filled with blood to get hard. Put simply, Cialis® works by increasing blood flow to the penis and therefore makes it easier to get and keep an erection.

Erotic stimulation (by physical touch, erotic thoughts, smells, etc.) causes the local tissues to release nitric oxide (NO), which increases the amount of a chemical called cyclic guanosine monophosphate (cGMP). cGMP causes the muscles on the sides of the penis, the corpora cavernosa, to relax allowing blood to rush into the penis. At the same time, veins that drain blood from the penis get compressed causing the increased blood to be trapped in the penis causing an erection. An enzyme called phosphodiesterase-5 breaks down cGMP leading the penis to return to its flaccid state. PDE5i, like Cialis®, block this enzyme leading to higher levels of cGMP and improving the ability to get and maintain an erection.

Cialis® and Viagra® are each brand name medications used to treat erectile dysfunction. While they both start working within about an hour, Viagra® remains effective for about 4 hours, while Cialis® can remain effective for as long as 24-36 hours. Keep in mind that these medications do not automatically induce erections—you need to be aroused for them to work—so the amount of time they remain in your system just reflects the window during which they make it easier to get an erection. While Viagra® is only taken on an as-needed basis and requires some planning ahead, certain strengths of Cialis® can be prescribed as a daily medication, which means you don’t need to plan as carefully.

How should I take Cialis®?

Cialis® absorption is not affected by food and can be taken with or without food.

  1. Cialis pills takes 30 to 60 mins to work


    Take it at least 30–60 minutes before sex, when prescribed as needed.

    Take it  at the same time each day without regard to when you have sex, when prescribed for daily use.

  2. Take Cialis pills at least 2 hours before sex


    Some people have better results when they take the as-needed dose of Cialis® at least 2 hours before sex.

  3. Cialis pills will stay active in your body for up to 36 hours


    Cialis® is a long-acting drug and will stay active in your body for up to 36 hours.


Cialis® rarely causes side effects, and when it does, side effects are typically mild. These can include flushing and sweating, headaches, nausea, indigestion or diarrhea, runny nose or congestion, muscle aches, and back pain.

Yes. Ro connects you with a US-licensed healthcare provider online who will review your information and prescribe Cialis®, if appropriate. Keep in mind that Cialis® is not available without a prescription in the United States and therefore, websites offering “over-the-counter” Cialis® without a prescription are likely not reliable or trustworthy sources for this medication. With Ro, you can always be sure you are getting genuine medication with active ingredients in the correct amount without harmful additives. Ro dispenses drugs manufactured by pharmaceutical companies that are regulated by the FDA.

Ro offers branded Cialis® and its generic, tadalafil, to treat ED. They are both FDA-approved to treat ED. They can be taken as needed (from 5 mg to 20 mg) or daily (in the 2.5 mg and 5 mg doses) to treat ED.

In addition to as needed dosing, Cialis® is also approved for daily use in the 2.5 mg and 5 mg doses. This creates a steady amount of medicine in the blood and completely eliminates the need to plan for sex. With daily Cialis®, treatment for ED becomes part of your daily routine.

Most men who are eligible for ED treatment can take daily Cialis® with certain exceptions, including airline pilots, air traffic controllers, and people taking certain medicines (e.g., some HIV medicines, certain antibiotics and antifungals). You should speak with your provider to determine if daily Cialis® is an appropriate treatment option for you.

Tadalafil is the active ingredient in Cialis®. Cialis® was originally patented and sold by Eli Lilly. It is FDA-approved to treat ED and urinary symptoms due to BPH. After the patent expired in 2018, the FDA gave permission to other drug companies to manufacture a generic version of Cialis®. Generic drugs act the same way in the body and are expected to produce the same effects as the original brand-name drug. Generic drugs are generally much cheaper than the original brand name drug, and most drugs prescribed in the US are generic.

The Roman way

How Roman works

Technology has enabled a massive shift in the way healthcare can be provided. With Roman, you can receive expert quality care from your phone or computer, without ever leaving the comfort of home.

Do everything from your mobile device

Free 2-day shipping (discreetly packaged)

No commitment—cancel whenever you want

Answer a few questions about your health.

Report your symptoms and medical history to a US-licensed healthcare professional.

A US-licensed healthcare professional will determine the treatment best suited for you and then follow up via secure messaging in your Roman portal.

Receive free, 2-day shipping for treatment.

If treatment is prescribed, you'll receive it within 2 days—packaged discreetly and shipped for free.

Get free follow-ups for ongoing care.

Schedule follow-ups with your physician or nurse practitioner. Note: you should continue to receive regular, in-person care in addition to using Roman.

Important safety information

What you should know before taking Cialis

Discover more from Ro

Feel your best without the hassle

Explore our full range of products and prescription treatments. If appropriate, a provider will create a personalized treatment plan for prescription treatments.

  • Hair loss

    More hair, less hassle. Get medication prescribed by a US-licensed healthcare provider. All from the comfort of home.

    Learn more
    finasteride, generic Propecia, and minoxidil, generic Rogaine, treatment from Ro
  • Testosterone support

    You can't get this blend anywhere else—and it includes ashwagandha for testosterone support and magnesium to support muscular health.

    Learn more
    Roman testosterone support supplements
  • Premature ejaculation

    We offer prescription medications and an OTC treatment that is clinically proven to help you last longer.

    Learn more
  • Weight loss

    Our 12-month Body Program helps you lose an average of 15% body weight by pairing GLP-1 medication with personal coaching.

    Learn more
    Ozempic pens with the Body Program equipment
  • Roman Daily Multivitamin

    Doctor-formulated with 23 nutrients, Roman Daily is optimized to support men’s health and physical activity.

    Learn more