Cialis (Tadalafil) 101 Guide: What Is It, How It Works, And How To Properly Take It

If you’re looking for an erectile dysfunction treatment that keeps you in the game longer, Cialis might just be the MVP. Known for its longer-lasting effects, this little pill gives you the freedom to be spontaneous without having to plan your entire evening around it.

In this guide, we’ll break down how Cialis works, how effective it is, and how to take it properly—so you can focus on what really matters.

What Is Cialis and How Does It Help With ED?

Cialis is a prescription medication for erectile dysfunction (ED) that works by boosting blood flow where it counts. Its active ingredient, Tadalafil, is a PDE5 inhibitor—which basically means it blocks the enzyme that messes with your ability to get and stay hard.

Here’s how it works:

1. Your blood vessels relax and widen, making it easier for blood to flow into your penis.

2. When you’re aroused, that increased blood flow leads to a firmer, longer-lasting erection.

3. The effects stick around for up to 36 hours, giving you a lot more flexibility than other ED meds.

Cialis won’t magically spark desire—you still need to be aroused for it to work. But when the moment’s right, it’s got your back.

How Effective Is Cialis?

Spoiler alert: It works. Really well.

📌 Over 80% of men saw improvements in ED in a clinical trial of 4,000 participants.

📌 It lasts up to 36 hours, so no more awkwardly checking the clock.

📌 Starts working in just 30 minutes, giving you more room for spontaneity.

📌 Fewer side effects compared to other ED treatments, making it easier to take regularly.

Compared to other ED meds, Cialis is like having a weekend pass instead of a one-night ticket. You’re not stuck in a 4-hour window—you get to enjoy the moment whenever it happens.

How Long Does Cialis Take to Work, and How Long Does It Last?

Cialis is the marathon runner of ED meds—it sticks around for up to 36 hours, which is way longer than Viagra’s 4-hour window.

But let’s clear something up—you won’t be walking around with an erection for 36 hours straight (thankfully). Instead, Cialis keeps you ready when the moment’s right within that timeframe, so you’re not racing against the clock.

How to Take Cialis (Tadalafil) for Maximum Effect

Cialis comes in two forms:

✔ Oral tablets (5mg, 10mg, 20mg) – Can be taken with or without food.

✔ Liquid form (2.5mg/mL) – Best taken on an empty stomach for faster absorption.

Recommended Dosage for ED

✅ Start with 10mg at least 30 minutes before sex.

✅ If 10mg doesn’t do the trick, increase to 20mg.

✅ Don’t take more than once per day—it won’t make it work better, just increases the risk of side effects.

Meal Timing Matters

Cialis doesn’t mind what’s on your plate, but if you take it with a heavy, high-fat meal, your body might take longer to absorb it. If you want faster results, stick to a lighter meal before taking your dose.

What to Avoid When Taking Cialis

💊 Nitrates (for chest pain/heart conditions)

• Mixing Cialis with nitrate meds can cause a dangerous drop in blood pressure. That means dizziness, fainting, and in severe cases, a heart attack or stroke.

💊 Alpha Blockers (for high blood pressure or prostate issues)

• When combined with Cialis, your blood pressure could drop too low, making you feel lightheaded or even pass out.

💊 sGC Stimulators (for heart failure or pulmonary hypertension)

• Like nitrates, these medications relax blood vessels, which can tank your blood pressure dangerously when mixed with Cialis.

🚨 If you’re taking any of the above, tell your doctor before starting Cialis. If you experience severe dizziness or fainting, stop taking your meds immediately and seek medical help.

Need a Check-in? We’ve Got You

At noah™, we offer free follow-up consults, so if you’re experiencing any side effects, just check in with your doctor. We’ll help you figure out the next steps and make sure you’re getting the safest, most effective treatment.

What to Avoid When Taking Cialis

🍷 Alcohol

Excessive alcohol can make Cialis less effective and increase the risk of side effects like dizziness and low blood pressure. If you want the best results, keep it light on the booze.

🍊 Grapefruit

Grapefruit isn’t just a breakfast staple—it’s also a troublemaker when mixed with Cialis. The fruit blocks your body from breaking down the medication properly, leading to stronger-than-intended effects (or unwanted side effects). If you’re on Cialis, skip the grapefruit juice.

🥛 Dairy & Fatty Foods

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That cheese-laden burger or creamy latte might slow down how fast Cialis gets into your system. High-fat foods and dairy can coat your stomach and intestines, delaying absorption and making Cialis take longer to work. If you want fast, predictable results, go for a lighter meal instead.

💊 Other ED Medications (Like Viagra)

You should never double up on ED meds. Even after Cialis wears off, its effects can linger in your bloodstream for 24 hours. Taking another ED medication too soon can spike the concentration of active ingredients, increasing your risk of dangerously low blood pressure. If you’re switching between Cialis and Viagra, wait at least 24 hours before taking another dose.

Potential Side Effects of Cialis

Like any medication, Cialis comes with some potential side effects—most of them are mild and temporary, but it’s good to know what to expect.

Common Side Effects:

• Headache – The most frequently reported side effect. Staying hydrated can help.
• ‍Upset Stomach – Some mild indigestion is possible, but usually fades quickly.
• ‍Back Pain & Muscle Aches – This is due to how Cialis affects blood flow and usually resolves on its own.
• ‍Flushing (Reddish Skin) – A temporary warmth or redness, particularly in the face or chest.
• ‍Stuffy or Runny Nose – Can feel like mild congestion, similar to allergies.
• ‍Diarrhea – Not common, but it can happen.

Serious Side Effects (Seek Medical Help ASAP):

🚨 Priapism – If you get an erection lasting longer than 4 hours, seek emergency medical attention immediately.

🚨 Severe Dizziness, Nausea, or Chest Pain – If this happens during or after sex, do not ignore it. Call a doctor right away.

🚨 Sudden Hearing Loss – If you experience a sudden drop in hearing, contact a healthcare provider immediately.

🚨 Vision Changes or Loss – If you notice blurred vision or sudden vision loss in one or both eyes, stop taking Cialis and get medical help.

Cialis vs. Tadalafil: What’s the Difference?

So, what sets Cialis apart from Tadalafil? Not much, really.

💊 Same Active Ingredient – Cialis is Tadalafil, just with a brand name and a higher price tag. Both work exactly the same way to treat ED and last up to 36 hours in your system.

💰 Cost Differences – Cialis is the branded version, while Tadalafil is the generic equivalent—meaning Tadalafil is just as effective but typically more affordable.

📦 Appearance & Branding – Cialis comes in its distinctive yellow, almond-shaped pill, while generic Tadalafil may vary in color, shape, or packaging depending on the manufacturer.

At the end of the day, choosing between Cialis and Tadalafil is mostly about preference and cost. If you want the same results at a lower price, Tadalafil might be your best bet.

When it comes to treating erectile dysfunction, Cialis and Tadalafil are essentially the same—just with different names and price tags. But if you’re wondering about the finer details, here’s the breakdown:

1. Brand vs. Generic

• Cialis is the brand-name ED medication, manufactured and marketed by Eli Lilly, a major pharmaceutical company.
• ‍Tadalafil is the generic version of Cialis—same active ingredient, same effectiveness, just produced by different manufacturers.

2. Physical Appearance

• Cialis pills are yellow, oval-shaped, and film-coated, available in 2.5mg, 5mg, 10mg, or 20mg doses.

• ‍Tadalafil tablets might look different—shapes, colors, and coatings vary by manufacturer—but the effects remain the same.

• The difference in looks is purely cosmetic—both medications work exactly the same way in your body.

3. Cost: Cialis (Branded) vs. Tadalafil (Generic)

💰 Brand-name Cialis comes with a premium price tag due to branding and marketing by Eli Lilly.

💰 Generic Tadalafil is made by multiple manufacturers, meaning more competition—and lower prices for you.

Here’s a price comparison in Singapore:

• Cialis 20mg (8 tablets): S$205.20‍
• Tadalafil 20mg (8 tablets): S$116.64‍
• Cialis 5mg (30 tablets - 1 month supply): S$226.90‍
• Tadalafil 5mg (30 tablets - 1 month supply): S$145.80

That’s a difference of up to 2-3x the price!

So, Which One Should You Choose?

If you prefer a branded product and don’t mind paying extra, Cialis is a solid option. But if you want the same effectiveness at a fraction of the cost, Tadalafil is the way to go—it does the exact same job without the premium price tag.

Bottom line? Your wallet will feel the biggest difference.

Cialis 5mg vs. Cialis 20mg: Which One Is Right for You?

Cialis comes in two common doses—5mg and 20mg—and while they contain the same active ingredient (Tadalafil), they work differently based on how you take them. Here’s how to decide which one suits you best.

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Cialis 5mg (Daily Cialis): The Low-Dose, Everyday Option

✅ Why Choose It?

• No need to plan ahead – Since it’s taken daily, Cialis 5mg stays in your system, meaning you can be ready anytime without waiting.
• ‍More spontaneous – No need to take a pill right before sex—it’s always working in the background.
• ‍Fewer side effects – Lower doses typically mean milder or fewer side effects compared to the stronger 20mg dose.

❌ Potential Drawbacks

• Takes time to build up – Unlike the 20mg dose, which works within 30–60 minutes, Cialis 5mg needs a few days of regular use before it reaches full effectiveness.
• ‍Mild side effects might last longer – Since it’s in your system daily, minor side effects like nasal congestion or headaches can be more persistent.

Cialis 20mg (On-Demand Cialis): The Potent, As-Needed Option

Cialis 20mg is taken only when you need it, making it a better choice for men who prefer occasional use rather than a daily pill.

✅ Why Choose It?

• Stronger effects – Cialis 20mg delivers a more potent effect compared to the 5mg dose, making it ideal for men who need a stronger boost.
• ‍Fast-acting – Works in 30 to 60 minutes, so you don’t have to take it every day.
• ‍Lasts up to 36 hours – A single dose can keep you ready for an entire weekend.

❌ Potential Drawbacks

• More noticeable side effects – Because it’s a higher dose, the chances of experiencing headaches, flushing, or muscle aches increase.
• ‍Less spontaneity – You’ll need to plan ahead, as it takes some time to kick in.

Which One Should You Choose?

• Go for Cialis 5mg if you want:

✔️ More spontaneity (no need to time your dose)

✔️ A milder, everyday option

✔️ Fewer side effects

• Go for Cialis 20mg if you want:

✔️ A stronger effect for occasional use

✔️ Faster results within 30-60 minutes

✔️ A single dose that lasts for up to 36 hours

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Go for Cialis 20mg if you want: 

• Fast-acting – Kicks in within 30 to 60 minutes, making it one of the quicker options for ED treatment.
• Less affected by food – Unlike some other ED meds, Cialis doesn’t lose much effectiveness when taken with a meal, so you don’t have to worry about timing it around food.
• ‍Long-lasting effects – Cialis 20mg is one of the longest-lasting ED medications, keeping you ready for up to 36 hours—perfect for a weekend of spontaneity.

❌ Potential Drawbacks

• Requires planning – You’ll need to take it ahead of time, which might interrupt the moment if you’re used to more spontaneous experiences.
• Higher chance of side effects – Since it’s a stronger dose, some men experience headaches, flushing, or muscle aches more intensely than with the lower 5mg daily dose.

Ultimately, Cialis 20mg is ideal for men who want a strong, long-lasting effect and don’t mind taking a pill before the action starts. If you’re unsure which dosage is right for you, consult a doctor for personalised advice.

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Frequently Asked Questions About Cialis

Cialis vs. Viagra: Which Is Better for ED?

Both Cialis and Viagra are effective ED treatments that work by increasing blood flow to the penis, but they differ in how long they last and how they interact with food.

✅ Why Some Men Prefer Cialis 20mg:

• Lasts up to 36 hours – Compared to Viagra’s 4-hour window, Cialis lets you stay ready for longer.
• Less affected by food – While both work best on an empty stomach, Cialis isn’t as impacted by heavy meals as Viagra is.

❌ Why Some Men Might Prefer Viagra 100mg:

• Shorter duration – While Cialis’s long-lasting effects are a plus for many, some find the 36-hour window too long.
• Potential for persistent side effects – Since Cialis stays in your system longer, any side effects (like headaches or flushing) might stick around longer than they would with Viagra.

At the end of the day, the best choice depends on your lifestyle and preference. If you want something that works quickly and is out of your system in a few hours, Viagra might be a better fit. If you prefer flexibility without worrying about timing your pill before sex, Cialis wins.

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Is 20mg of Cialis the Same as 100mg of Viagra?

Not exactly. Cialis 20mg and Viagra 100mg are the highest doses for each medication, but they don’t work the same way. Cialis lasts much longer (up to 36 hours), while Viagra has a shorter but strong effect (about 4-5 hours).

If you’re unsure which is better for you, consult your doctor for personalised advice.

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Can You Exercise After Taking Cialis?

🚴 Exercise is great for overall sexual health, but working out immediately after taking Cialis isn’t recommended.

Because Cialis lowers blood pressure, intense exercise can cause dizziness, lightheadedness, or even fainting due to excessive blood flow.

💡 Best approach? Wait a few hours after taking Cialis before hitting the gym to let your body adjust to the medication.

Can Cialis Be Taken with Other ED Medications?

🚫 Mixing Cialis with other ED medications like Viagra (Sildenafil) or Levitra (Vardenafil) is not recommended.

Most ED medications work as PDE5 inhibitors, meaning they increase blood flow to the penis by relaxing blood vessels. Taking more than one at a time doesn’t mean better results—it just increases the risk of side effects.

Potential Risks of Combining ED Medications:

• Dizziness, headaches, and flushing – Common but intensified when medications are stacked.
• Dangerously low blood pressure – Can lead to fainting or serious health risks.
• ‍Priapism (prolonged erection lasting more than 4 hours) – A medical emergency that can cause long-term damage.

💡 Bottom line? Stick to one ED medication at a time, and if Cialis isn’t working for you, talk to a doctor about alternatives rather than doubling up.

At noah, our doctors can help you get to the root of your ED and determine the best treatment for you—whether that’s Cialis, Viagra, or another option that suits your needs. Plus, if needed, they can prescribe the right medication and have it delivered discreetly to your door.