Men's Health Specialists

ED Pills Guide

Learn Everything About ED Pills

The first ED pill, Sildenafil, was introduced in 1998 and it is not an exaggeration to say that ED pills are one of the most successful – commercially and in terms of results - drugs, ever! 

Because of ED pills, hundreds of millions of men have been able to regain their erections and salvage their sex lives.

Since then, various pharmaceutical companies have introduced medication similar to Sildenafil, meaning that men have more treatment options than even. However, with more options also comes more confusion. This guide aims to provide you all the information you need to understand how ED pills work, if its a safe and effective treatment for your case and also choose which is the best treatment option based on your preferences and needs.


A Short Primer on Erections

How Do ED Pills Work?

Is It Safe to Take ED Pills?

Which ED Pill is The Best?

ED Pills Daily vs On-Demand

A Short Primer On Erections

The penis is quite a complicated and fascinating organ. The shaft is the longest part of it. The head or glans is at the end of the shaft. The opening at the tip of the head, where urine and semen come out, is called the meatus. Inside, two cylinder-shaped chambers called the corpora cavernosa run the length of the penis. They have a maze of blood vessels, tissue, and open pockets.

The urethra, the tube that urine and semen flow through, runs along the underside of them, in the spongy tissue of the corpus spongiosum. Two main arteries (one in each of the corpora cavernosa) and several veins move blood in and out. Nerves relay messages to and from other parts of your body.

The corpora cavernosa – the erection bodies - are made of spongy tissue and have the ability to gain blood volume and grow in size.

Throughout the day, arteries supplying blood to your penis are only partially open. This provides the blood flow needed to keep your tissue healthy. In response to sexual (physical or mental) stimulation, your brain sends signals to trigger a hormonal response that allows those same arteries to open completely.

Open arteries allow more blood to enter the corpora cavernosa. The blood enters faster than it can leave through the veins. The veins get compressed, trapping blood in your penis. This chain reaction lets you achieve and maintain an erection. When your brain stops sending signals that indicate sexual arousal, the hormonal response ends. Your arteries go back to their normal state and your penis returns to a flaccid state.

As such, in order for men to achieve an erection, a number of things need to be functioning correctly:

• The nerves in the penis and those “signalling” the sexual stimulus to the penis must be functioning properly;

• The blood circulation to the penis must be adequate and the internal erection mechanism must be intact;

• The veins must be able to “trap and keep” the blood inside the penis; and

• There must be sexual stimulus from the brain.

Interference with any of these systems may result in sporadic or permanent erection problems.

By far the most common cause of erectile dysfunction is endothelium dysfunction, which is also often abbreviated as ED. In brief, so as not to overcomplicate things, the endothelium is a layer of cells that is found throughout the erection mechanism (the corpora cavernosa) and these need to be healthy in order for the erection bodies to expand adequately so as to trap the blood flowing in the penis (the expanding erection bodies trap the blood by effectively becoming engorged and blocking the veins that take away the blood from the penis).

If the endothelium cells (and the accompanying smooth muscle tissue) are not healthy this means that the expanding erection bodies have lost some of their elasticity and although enough blood flows in the penis, the erection bodies do not expand adequately to trap it so as to get an erection.

Everything that is bad for your cardiovascular and heart health since endothelium dysfunction is the first stage of cardiovascular disease (the endothelium cells are lining all the arteries in our bodies and cardiovascular disease starts when the endothelium becomes damaged). You might have come across the list of things that are bad for the endothelium, which include:

• Bad diet and obesity (and all the associated health issues such as fatty liver disease, metabolic syndrome and diabetes)

• Lack of exercise

• Low Vitamin D

• Smoking

• Stress

• Lack of or bad quality sleep

how Do ED Pills Work?

As explained previously, erections are caused by increased penile blood flow resulting from the relaxation of penile arteries and the smooth muscle cells.

This process involves a few steps; following sexual stimulation the local nerves and the endothelial cells in the penis release nitric oxide, which in turn increases the production of a chemical called cGMP (cyclic guanosine monophosphate), which relaxes the smooth muscles and increases blood flow. Another chemical, found in the erection mechanism, called phosphodiesterase type 5 (PDE5) breaks down cGMP and reduces its concentration. ED pills, effectively block PDE5 (that is why they are called PDE5 inhibitors), thus allowing more cGMP to form and act on the erection mechanism smooth muscle, which in turn improves erections.

Is it safe to take ED pills?

This is a question that lingers in the mind of many men and it is not uncommon for men to think that taking an ED pill might give them a heart attack or some other scary side effect, like impaired vision.

The reality is that for the vast majority of men, ED pills are not only very safe to take, but there is research to suggest that they can also have significant health benefits beyond better erections, including improved cardiovascular health, prostate function and even cancer prevention!

Having said that, there are some categories of drugs, such as nitrates and alpha blockers, that interact with ED pills and can lead to hypotension (low blood pressure) which can be dangerous. As such, you should always consult a doctor before taking an ED pill, especially if you are on any other medication. Beyond that, since the aim of taking ED meds is to have sex, if you recently had any serious health issues, have been advised to avoid strenuous activities or you are in general very unfit then consult your doctor if it is safe, from a cardiovascular perspective, to have sex.

Another concern about ED pills are temporary side effects such as muscle aches, back pain, head-aches, blocked nose, bowel irritation and vision problems. These issues are usually dosage dependent and occur in less than 10% of men. For many men these issues are quite tolerable and transient. However, if you are concerned about or experience such issues then inform your doctor and he might recommend a different dosage or pill.

Which ED Pill Is The Best?

There are currently 4 commercially available ED pills that all work in the same way (they all belong to the class of drugs called PDE-5 inhibitors) but exhibit some significant differences. The four categories and their main characteristics are the following:


Dosage Available: 25mg (low dose), 50mg (standard dose), 100mg (high dose)

Duration of Effect: 4-6h

Cost: Low (generic available)

Interaction with food and alcohol intake: Food and alcohol intake can affect action

Side-effects: Low


Dosage Available: 2.5mg & 5mg (for daily intake), 10mg (standard dose), 20mg (high dose)

Duration of Effect: 36h

Cost: Low (generic available)

Interaction with food and alcohol intake: None

Side-effects: Very Low


Dosage Available: 50mg (low dose), 100mg (standard dose), 200mg (high dose)

Duration of Effect: 4-6h

Cost: High (still patent protected)

Interaction with food and alcohol intake: Food and alcohol intake can affect action

Side-effects: Low


Dosage Available: 5mg (low dose), 10mg (standard dose), 20mg (high dose)

Duration of Effect: 4-6h

Cost: High (still patent protected)

Interaction with food and alcohol intake: Food and alcohol intake can affect action

Side-effects: Low

Most men have heard of Sildenafil simply because it was the first pill to become available. To help you understand which ED pill might work best for you, we will look at each characteristic in turn.

Efficacy & Dosage                                    

Winners: Sildenafil & Tadalafil

All ED pills exhibit similar effectiveness in terms of improving erections and the majority of men (70%) with benefit from taking them. There are no significant differences in their efficacy but on an individual level one type of pill can potentially work a little better than others. In terms of efficacy, meaning how strong erections will be, the most important parameter is the dosage. All pills come at low, standard and high doses. Most men start at the standard dose and will switch to higher if their response is not good or to the lower one if they experience any side effects.

In a recent study that compared standard dosage efficacy of the different ED pills, sildenafil (slightly higher efficacy) and tadalafil came on top followed by vardenafill and avanafil in the last place.  

Duration of Effect

The winner: Tadalafil

An important clarification before we delve into the details. By duration of effect we do not mean how long an erection lasts if you take an ED pill.  In general erections only last (with or without ED pills) for as long as you are sexually stimulated or until you orgasm. As explained, ED pills help you get stronger erections while sexually stimulated, they do not prolong erections or ejaculation time. With that in mind, the duration of effect of an ED pill refers to the time that the medication is active in your body. So for example if you take a pill which has a duration of effect of 4-6 hours and you have sex within that time window then this will improve your erections, however if you try to have sex 12h later then the pill’s effect on your erections will have worn out and you would need to take another pill.

In that respect, the ED pill with the longest duration of effect is Tadalafil, which lasts 36h whereas all the others have a duration of effect between 4-6h. For this reason, most patients prefer Tadalafil after they try it (and we usually recommend it) since it allows a bigger window of opportunity to have sex and do so multiple times without needing to take another pill, which can be inconvenient and costly.

Another very important aspect of the long duration of effect of tadalafil is that many men will prefer and/or be recommended to take a daily ED pill as opposed to on demand (i.e. before sex) so that they are constantly exposed to the beneficial effects of the medication (this is very important as will be explained later). In order to achieve this with tadalafil, you only need to take 1 pill per day as opposed to 4-6 pills daily with the other medication.


The winners: Tadalafil & Sildenafil

Tadalafil and Sildenafil are off patent protection meaning that any drug manufacturing company can manufacture generic versions of the medication. Generic medications are exactly the same as the original branded ones but are much cheaper. As a result, generic Tadalafil (off patent since 2017) and Sildenafil (off patent since 2013) have very low prices whereas Vardenafil and Avanafil are still under patent protection and are significantly more expensive.

Interaction with food and alcohol

The winner: Tadalafil

It is generally recommended that Sildenafil, Vardenafil and Avanafil are taken with an empty stomach since fatty foods and alcohol can affect their efficacy.

Tadalafil on the other hand is not affected by any food or alcohol intake. This seems to be another reason why patients overwhelmingly prefer Tadalafil compared to the other ED pills since it requires less planning or imposes less restrictions when taking the medication.


The winner: Tadalafil

Some men (around 10%) who take ED pills will experience side-effects including headache, flushing, muscle aches, dyspepsia and nasal congestion. Similar to efficacy, the occurrence and severity of side-effects is mainly dose depended. In a recent meta-analysis study comparing standard dosage side-effects of the different pills, Tadalafil had the lowest overall rate of all adverse events whereas vardenafil, avanafil and sildenafil had similar overall adverse events.


Based on our analysis of the different ED pills characteristics, it becomes obvious why the vast majority of men who first try ED medication prefer Tadalafil, which is the drug that also displays the highest treatment adherence.

Beyond that, another very important advantage is that tadalafil (the 2.5mg or 5mg dose) can be also taken daily. As explained below, taking a pill daily as opposed on demand has some very significant advantages.

ED pills daily vs on-demand

Although ED pills before sex will not arrest the deterioration of your erection issues, the reality is that there is scientific evidence to suggest that taking an ED pill daily as opposed to on demand (i.e. before sex) will not only slow down the progress of ED but in some cases even resolve your erections issues altogether.

But Why?

The answer, is that taking an ED pill daily, which works around the clock, will also improve your night erections, which as mentioned earlier, is your body’s way to preserve the health of your erection mechanism. Research suggests that better night erections, will mean slower progress or even reversal of ED.

Another benefit is that if you take an ED pill daily, your body will become accustomed to any potential side-effects and these will stop being bothersome.

In terms of cost, generic daily tadalafil (2.5mg or 5mg dose) supply of one month will usually cost the same as 8 generic on demand ED pills (tadalafil or sildenafil).

For this reason, we usually recommend the daily tadalafil regimen.