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The Erection Process: How Does It Happen And How Erectile Dysfunction Can Disrupt It

The Erection Process: How Does It Happen And How Erectile Dysfunction Can Disrupt It

What's up everyone? It's Rich! Ever heard the saying, "It's not about the destination, but the journey?" Well, that applies to the erection process, too. It's not a light switch that flips on and off instantly. It's a complex journey involving various stages, numerous body systems, and intricate neurophysiology (including social and emotional settings, too!).

As erections are a natural part of male sexual response, they can be a source of confusion and anxiety for many men. Understanding the erection process, from the physiological mechanisms to the psychological factors involved, can help men better understand their own bodies and address any concerns they may have about their sexual performance.

In this comprehensive guide, we will explore the 5 stages of an erection, a little bit on the sexual response cycle, the neuroscience behind it, and real-life examples that demonstrate why some men lose their erections during sex and why sometimes they're not erect for sex.

Disclaimer:, (We, I, Us) is a professional review site that tests men’s health products thoroughly and provides educational information that shouldn't be misconstrued as medical advice. We are independently owned and the opinions expressed here are our own. We are NOT doctors. We can’t diagnose you. If you need a diagnosis, prognosis or medical advice, go to your doctor. Read more about our policies and disclosures here.

The 5 Stages of an Erection

The erection process can be broken down into five distinct stages, each involving different physiological and neurological processes:

  • Arousal: The first stage of an erection is sexual arousal, which can be triggered by the 5 senses (physical touch, visual stimulation, etc.) or mental fantasies. During arousal, the brain sends signals to the nerves in the penis, initiating the erection process. Also, known as the Latent phase where blood begins filling the penis.

  • Filling: As the nerves in the penis receive these arousal signals, they trigger the relaxation of the smooth muscles within the corpora cavernosa. This allows blood to flow into the spongy tissue, filling the open spaces and causing the penis to become engorged. Also known as penile tumescence or the start of an erection. Some people might refer to this stage as a “semi-erection”.

  • Erection: As more blood flows into the penis, the pressure increases, and the veins that normally drain blood from the penis become compressed. This traps the blood within the corpora cavernosa, causing the penis to swell and become erect.

  • Rigidity: The ischiocavernosus and bulbocavernosus muscles, located at the base of the penis, contract during the erection process. This helps to further increase pressure within the corpora cavernosa, resulting in a fully rigid erection. This stage usually occurs before climax.

  • Resolution: After ejaculation or when sexual arousal subsides, the brain stops sending arousal signals, and the smooth muscles within the penis contract. This allows blood to flow out of the corpora cavernosa, and the penis returns to its flaccid state. Also known as “penile detumescence” where the penis returns to its normal flaccid state.

The Erection Process And Sexual Response

The process of an erection is heavily nuanced and more complex than you think. Some people who are poorly misinformed about erections also believe the penis "acts" like a muscle and that it can flex when a man sees someone attractive. Others think it can be commanded at will or is always an automatic reaction when presented with the opportunity of having sex or when masturbating.

Let's debunk that.

Neuroanatomy and Human Sexual Behavior

"Sexual behavior is regulated by both subcortical structures, such as the hypothalamus, brainstem, and spinal cord, and several cortical brain areas acting as an orchestra to finely adjust this primitive, complex, and versatile behavior. At the central level, dopaminergic and serotonergic systems appear to play a significant role in various factors of sexual response, although adrenergic, cholinergic, and other neuropeptide transmitter systems may contribute as well."

An erection is a sexual response to sexual stimuli (again 5 senses or mental fantasies). Men are often known to have a spontaneous desire "style" while women have been shown to be more of a “responsive” type when it comes to desire. But it’s a spectrum and one can sway back and forth between the two.

This means that depending on the conditions or circumstances for sex, your style could be spontaneous or response driven. Both are NORMAL. But, It’s about understanding your sexual behavior and how you respond sexually as well as what your partner’s style is to improve the communication between you two when it comes to sex.

Erections And Sexual Response

Every guy is different when it comes to sexual response, and how they respond to start the process of an erection.

neurophysiology of the sexual response infographic

In short, desire and sexual stimuli are NEEDED to start the sexual response cycle in men. Sexual arousal begins with an erection. How an erection happens involves sensorial signals sent from the dorsal nerve, through the spine (activating pro-erectile spinal neurons), and to the brain to induce smooth muscle relaxation in the penis. Neurotransmitters in the brain are signaled/stimulated and nitric oxide is released by the endothelium parasympathetic stimulation of pelvic nerves.

As a result, blood vessels of the corpora cavernosa relax and open up, filling up with blood. The blood then gets trapped under high pressure by a series of valves, creating an erection. Once your brain stops sending signals to indicate arousal, the erection process begins to reverse itself. The hormone response ends and the penis returns to a flaccid state.

Both sympathetic and parasympathetic nervous systems are involved (from arousal/excitement to orgasm/resolution) and the prudential nerves control contraction of the perineal striated muscles, which improve penile rigidity.

Erections also depend on spinal and supraspinal control in response to the 5 senses (touch, smell, taste, sight and auditory). You can also add "fantasy" as this also contributes to the sexual response and "psychogenic" erections. It is likely that reflexogenic and psychogenic stimuli act synergistically via the sacral parasympathetic route.

As you can see, an erection is a process and not to be confused with something being automatic or commanded at will for everyone. Everyone may respond differently than you.

Here Is A Step by Step Process Of An Erection (Simplified)

The process of an erection starts when sexual arousal initiates the release of neurotransmitters from the cavernous nerve endings. These causes the muscles to relax, resulting in increased blood flow to the penis and the following:

  1. Expansion of blood vessels and arteries from both the diastolic and systolic phases.

  2. Blood flow is trapped by expanding sinusoids.

  3. The subtunical venular plexus between the tunica albuginea and peripheral sinusoids is compressed. This, in turn, reduces venous outflow.

  4. Tunica limits reaching its capacity limits, occluding emissary veins present between the inner circular and outer longitudinal layers. This results in further decrease of venous outflow.

  5. An increase in PO2 (to about 90 mmHg) and intra cavernous pressure (around 100 mm Hg). These changes raise the penis from the dependent position to the erect state, which is the full-erection phase.

  6. Additionally, several hundred millimeters of mercury pressure increases due to the ischiocavernosus muscles' contraction, which leads to a rigid-erection phase.

The size and firmness of an erection (the quality of it) can vary greatly depending on the individual and their level of arousal. Studies also show that “nitric oxide” is another key driver for maintaining the erection.

How Hard Should Your Erections Be To Have “Penetrative” Sex?

Scientists and researchers often use an erection hardness scoring or the IIEF-5 (international index of erectile dysfunction) to evaluate hardness and satisfaction with overall erection quality/ability to perform.

An erection hardness score of at least 3 is what researchers consider "enough" to penetrate a partner while a score of 4 is the maximum scoring, also known as full rigidity.

erection hardness score infographic

What Can Disrupt Your Erections?

Sexual dysfunction plagues men of ALL ages. Also known as:

  • Erectile dysfunction (most common

  • Premature ejaculation (affects ⅓ men)

  • Delayed Ejaculation

There are also disorders associated with:

  • Arousal

  • Desire

  • Orgasm

  • And pain with erections or sex

Lastly, there are psychological components and relationship situations that most men overlook (please stop doing this!).

Let’s do a quick dive into each with some examples. Some dysfunctions might overlap.

Erectile dysfunction can disrupt your erection process

There are multiple types of erectile dysfunction and sometimes you can have more than one type! Here are some examples to go along with each one of them:

Vasculogenic ED (is the most common form of erectile dysfunction). Vasculogenic ED is an umbrella term and is often broken down into 3 categories:

Vasculogenic ED is the most common issue for men

  1. Arterial dysfunction: (anything that stops or slows blood flow to the penis) this is the MOST common form of vasculogenic ED. Impaired blood flow or reduced blood flow from poor lifestyle choices and poor dieting that eventually leads to inadequate erections.

  2. Endothelial dysfunction : (inability of the smooth muscle cells in the penis to relax/prevent vasodilation) - endothelial function declines from age-related diseases (diabetes, high blood pressure, atherosclerosis, and other conditions that affect the smooth muscle cells to respond to the process of an erection.

  3. Venogenic or venous dysfunction: (insufficient blood retention and incomplete smooth muscle relaxation of the penis to “maintain” the erection ….an example would be a venous leakage)


Endocrinological/Hormonal ED- think of thyroid issues, hypogonadism, and other hormonal imbalances that could play a role in arousal. Although testosterone may help enhance interest, frequency of sexual acts, and frequency of nocturnal erections, it has little to no effect on fantasy-induced or visually-induced erections.

The minimum threshold for normal nocturnal erections is about 200 ng/dl.


Psychogenic/Psychological ED

This is a MAJOR one that most guys undermine. It can be broken down into these categories:


  • Chronic disorders causing unresponsiveness

Situational (3 categories):

1) Partner related (psychological ED). Remember how we talked about sexual response and stimuli? Sometimes relationship conflict or not understanding desire styles may cause communication issues or a lack of arousal to start the process of an erection.

Maybe you’re a guy that leans towards “responsive desire” situations where you need all your senses stimulated (5 senses and mental fantasy) to trigger a sexual response.

There’s nothing wrong with that and it is common after the “honeymoon phase” in relationships-- where dopamine levels are no longer elevated from the “newness” or excitement of a new relationship (it’s not uncommon for long-term relationships to have periods of time where things get a little boring, too).

Dopamine and erections have a direct connection. So you need to keep the fire burning and keep switching things up to maintain an active and fulfilling sex life for you and your partner.

2) Performance related. Think of “performance anxiety” that men face. It’s a common occurrence in younger guys, but it can affect all ages.

  • One moment, you're hard and ready to go and then the next moment, negative thoughts flood your brain, or something your partner does that bothers you may push you back and forth between excitement and plateau phases (sexual response cycle), which prevents you from fully relaxing and becoming fully erect.

  • Guys with performance anxiety usually tend to have trouble achieving and maintaining erections. Some guys with performance anxiety may also experience premature ejaculation, which is orgasming or cumming within 1-3 minutes of intercourse.

  • Erections also happen from parasympathetic nerve responses.

  • But when we’re stressed, angry, frustrated, overworked, burnt out, anxious or experiencing relationship and intimacy issues, it can delay parasympathetic response which is needed for the sexual response cycle and erection process

When guys develop performance anxiety or psychological ED, it cause this vicious cycle of:

  • Is this normal? Do other guys experience this? Am I the only one?

  • Will it happen again?

  • I must get an erection!

  • I am unable to have a sexual thought

  • Will my partner reject me?

  • And so on

This is when “unpleasant” feelings replace sexual pleasure.
emotional erection cycle infographic

Fear and anxiety trigger nerve signaling to increase adrenaline, which can cause you to lose your erection. An increase in adrenaline and “sympathetic” nerve response leads to loss of erection.

3) Psychological distress (life events or "adjustment" related).

Sometimes life and stress gets the best of us. Maybe it’s work stress or a life-changing event that you can’t seem to focus on the eroticism of the moment with your partner or get in the mood. Or maybe it’s negative moods or unpleasant feelings preventing you from enjoying a quality life, including a quality sex life.


infographic of rich with spinal cords connection to neurological erectile dysfunction

Neurological ED - an example is "loss in penile sensitivity" due to a motorcycle accident with injury to the pelvic nerves. Or a decrease in the nerve response from a back/spinal cord injury.

Think of men in wheelchairs. The spine is SUPER important and you don’t want to injure your middle and lower back as there are two sections located in these areas that are responsible for “reflexive” and “psychogenic” erections.

Anatomic Issues - Injury or peyronie’s disease (curvature of the penis) is an example.

Pharmacological ED - Oftentimes, certain SSRIs used to treat specific mental disorders may potentially have side effects of sexual dysfunction in men. The same can be said for high blood pressure medication and other beta blockers that may reduce blood flow to the penis.

Always check your medicine cabinet and review potential side effects with your doctor. If there are any, work with a doctor to understand alternative options or ways to treat both issues. DON'T stop current medication without the guidance of a medical professional.

Male Pelvic Floor Dysfunctions - another piece of the pie.

Men can sometimes have a weak or untrained pelvic floor (hypotonic pelvic floor) while others may have a tight, tensed, strained or over contracting one (hypertonic pelvic floor).

Know that both can affect erections - being able to get one or to maintain one because there are nerves that pass through the pelvic floor muscles responsible for erection signaling. This and the BC muscles (for ejaculation) and IC muscles (contract for rigidity) play an important part, too.

For instance, a sedentary lifestyle, working a 9-5 desk job without getting up for a break (excessive and long term periods of sitting) , or even your typical "gamer" who sits all day may contribute to a weaken or untrained pelvic floor (if not physically active).

A guy who overtrains his pelvic floor without the guidance of a medical professional (pelvic floor specialist in male sexual dysfunction), or someone with poor posture and imbalances of the surrounding muscle groups (glutes, quads, TVA, hamstrings, etc.) may lead to a tight, or over contracting pelvic floor.

In some cases, guys who train P.E (enlargement) may even fall into the trap of kegeling excessively because of misguidance around the concept or injury to the pelvic floor from misuse of devices or P.E techniques that may even lead to things like hard flaccid syndrome or a strained pelvic floor.

FAQ On The Erection Process And How Erectile Dysfunction Can Disrupt It

Group of men learning from the questions and answers they have about the erection process

Q1: What are the stages involved in the erection process?

A: The erection process consists of five stages:

  1. Arousal: This stage involves senses or your fantasies.

  2. Filling: Your muscles relax and allow the penis to fill with blood, making you hard.

  3. Erection: The veins that normally drain blood from the penis become compressed. This traps the blood resulting in an erection.

  4. Rigidity: Your penis contracts further producing a fully hard erection.

  5. Resolution: After ejaculation, the brain stops sending you signals and releases the blood in your penis, resulting in a soft penis again.

Q2: What are some common misconceptions about erections?

A: The belief that the penis "acts" like a muscle that can flex (pop culture), that erections can be commanded at will, or that they are always automatic reactions when presented with sexual opportunities. These are simply NOT true.

Let's face it; guys are emotional creatures, too. Get it out of your head that your masculinity is defined by ONLY your penis and sexual prowess. We, too, require some form or level of connection to feel safe, & secure with someone we're going to have sex with to have an erection -- whether that's a little connection or you're someone who needs to have everything feel "just right". It's normal and more common than you think!

Q3: What are the two types of desire?

A: Spontaneous and responsive desire are two categories, or what I like to call, a spectrum that we can shift back and forth from, depending on the environment, relationship, and other factors going on in one's life. There is no right or wrong way to desire. Both are totally fine and normal.

Sometimes it can be out of nowhere (spontaneous), while other times you need a more "context specific" approach involving sexual stimuli to induce desire. Studies tend to point out that women may have a more "responsive desire style" whereas men may lean towards a more spontaneous desire style. But in respect to all gender types, sexualities and identities, these are just responses to biological factors and socialization.

Also...our society often perpetuates the idea that we are all "spontaneous" driven when it comes to sex (thanks to porn, social media, Hollywood movies, etc.). But that's not true, or the case for everyone.

It's the same misconception that men are supposed to be "always" ready and desire is always spontaneous, when in reality, a guy can sometimes be responsive, too. Or at certain times, be response driven depending on the circumstances or situation/approach to sex.

Q4: My friends always talk about getting erections right away with their partner's, but in my case, I don't always get one right away. Am I normal?

A: Whether you're participating in "hook up" culture or are in a long term relationship, an erection is not a flip of the switch. Sure, some of your friends may lean towards a "spontaneous" desire type where they have desire right away (ex: random or spontaneous mental fantasy causing them to get erect right away), but this may or may not always be the case or that you know of. 

Or maybe they don't tell you about the times when they DO experience performance anxiety or are more "responsive" at other times.

There is this myth that everyone should feel "desire" to have sex. This is simply not true. Sometimes we can be a "responsive" type and we may need to be aroused first for desire to come afterwards. It does not mean sex is off the table.

Rich from explaining to men that we are not always ready to perform when it comes to sex and sometimes we may be a more responsive type when it comes to desire

Example: Let's say you had a stressful day at work and your partner jumps your bones when you come home and you're not prepared, or "ready" for it. First off, it doesn't mean you're broken or "not normal" for not producing an erection, right away. And it doesn't mean sex is off the table because you're not approaching sex with an erection.

You just gotta get in there, relax, and have fun. The arousal process will start and desire will come after that...

The MOMENT you replace the word "perform" with the word "experience", you'll start to understand what sex truly has to offer...

OR replacing thoughts like "I need to perform" or "oh no, I'm not erect, yet" with words like "i'll get there, but right now, I'm going to eat my partner out" or "I'm going kiss their body all over", you'll start REALIZING the true "experience" of sex AND what sex truly has to offer. By doing so, you'll begin to have a more positive outlook around sex and will start enjoying sex, worry free. And soon enough, that erection will come as soon as you start focusing on the eroticism of the moment with a partner.

Q5: What factors influence erections?

A: Erections depend on the five senses (touch, smell, taste, sight, and auditory), and if the right "conditions" ( the right environment, privacy, trust, etc.) are met. Mental fantasy is also another factor, especially for "spontaneous" desire style types that also contribute to helping you achieve and maintain a hard erection.

As we age or your relationship grows older, sexual stimuli or the intensity may be necessary to keep the spark alive or for your aging body to respond, given there is enough "sufficient" sexual stimuli to induce an erection in the first place!

At the same time, repeating the same type of sex or stimuli without variety will result in complacency, boredom in the bedroom, or difficulty becoming aroused.

Q6: Are erections automatic reactions to sexual opportunities?

A: No, erections are not always automatic reactions to sexual opportunities. They require sexual arousal and stimulation. You're not going to automatically get hard when you have an opportunity in front of you unless you naturally tend to have a "spontaneous desire style", and you're the one approaching sex this way, then sure, maybe.

But not always, as life can throw you a curve ball. (See my answer to question 4).

Q7: How is the hardness of erections evaluated?

an erection hardness score of a 3 or 4 is considered enough for a man to penetrate their partner's during sex

A: Scientists and researchers often use an erection hardness scoring system or the International Index of Erectile Dysfunction (IIEF-5) to assess the hardness and satisfaction with overall erection quality. It provides a scale from 1 to 4 to measure.

Q8: What erection hardness score is considered enough for sex?

A: A score of at least 3 on the hardness scale is generally considered enough to penetrate a partner.

A score of 4 represents full erect, which is the maximum score and ideal.

Q9: What are some common conditions that can disrupt erections?

A: There are various sexual dysfunctions that can disrupt erections, including erectile dysfunction, premature ejaculation, delayed ejaculation, arousal disorders, desire disorders, orgasm disorders, and pain with erections or sex.

We've mentioned real life examples in the above sections. Reading this blog entirely might give you an "aha" moment when figuring out your own erections. Don't skip over sections!

Q10: What should I do if I experience difficulties with my erections?

A: If you experience difficulties with your erections, you should consult with a healthcare professional first and foremost. They can evaluate your specific situation, identify any underlying causes, and recommend appropriate treatment options, which may include lifestyle changes, medication, therapy, or other interventions tailored to your needs.

Closing thoughts On The Erection Process

Pause and take a deep breath... I know it's a lot to take it in, but you're not a robot, man. Although it would be nice to have an erection whenever we want or when the moment arises, you have to take a look at the bigger picture.

Rich from telling men to breathe and open their minds when learning about their erections and what sex truly has to offer

Simply put, sexual behavior is complex and can vary among individuals, including differences in desire styles and responses to sexual stimuli. Although it may not be simple, in fact, it's complicated when researching it, but if you start by drawing connections, you'll have a better idea of how to understand your own erections and desire type in your own personal relationships.

When it comes to our erections, there are SO many contributing factors... physiological, psychological, hormonal, neurological, and pharmacological factors... all of which can contribute to us having sexual dysfunctions and disrupting our erections. Whether that is erectile dysfunction or another form of sexual dysfunction.

The goal of this blog was to help people better understand the whole overall erection process so that you can understand your own sexual behavior and seek appropriate medical advice when experiencing difficulties with your erections.

Always consult a medical professional when in doubt. That's the first step when trying to rule out physical causes. Don't always guess or assume, when testing is needed. And if it's not a physical cause, don't overlook the mental aspect of it because even if you do start treatment for sexual performance issues--whether that's exploring:

  • PED5i's (Viagra or Cialis)

  • penis pumping (ex: bathmate)

  • shockwave therapy at a men's clinic (or at-home with The Phoenix device)

  • dieting and exercise

  • quitting smoking or vaping

  • sex therapy

  • stopping poor masturbation habits like using poor hand techniques (use a fleshlight instead)

  • etc.

There is still more to the pie that treatments or lifestyle changes can't help you with. You still have to put in the work, too, including talking to your partner(s).

Help them, help you.

As always, I appreciate you guys listening and hope that this helps you all better understand the erection process. If you're confused about anything I went over or have some questions feel free to reach out! Stay tuned for more guides like this!

Much love <3

- Rich

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