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The physiology and endocrinology of sexual arousal

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To figure out what goes on in the mind and body when a person feels tempted to engage in porn, fantasy or masturbation, I had to patch together the picture from a number of different sources. I couldn’t find one article that explained the whole thing really well.

Disclaimer: A lot of this is my own suspicions and hunches, supported by possibly unreliable science. The references I have included are mainly those that confirm my theories and fit well with my own personal experience. Therefore I make no claim to the scientific truth of the ideas below. As far as I know, everything below is correct and true, and I haven’t deliberately ignored any science that contradicts what I am saying, but I may have jumped to conclusions or made connections or assumptions that a scientist would hesitate to make. What I do claim, however, is that this stuff worked for me. As they say, ‘the proof of the pudding is in the eating.’

Sexual cues incite sexual desire

The initial stage in the sexual response cycle for men and women is desire, the urge for sexual intimacy or sexual gratification. Desire takes place mostly in the mind. It is related to your sex drive or libido. It could be considered the potential for sexual arousal or excitement. There are many cues that incite sexual desire; some are physical, others are psychological. These cues may come in a variety of stimuli. [Visual, Auditory, Olfactory, Kinesthetic, Tactile, Memory, Fantasy]…It is important to note that you may feel desire without any object of desire, just a feeling of wanting sexual gratification.1

Speaking personally, cues to sexual desire can be external (seeing women in short shorts, near-naked women on billboards) or internal (memories, random sexual thoughts, random sexual urges). It could be something like hearing the front door close, signalling that you are home alone, or throwing your bag on the bedroom floor after a long day of work, signalling the opportunity to ‘take a break’ (look at pornography or masturbate). Anticipation of potential sexual activity can be a cue.2

‘Arousal hormones’ are released

Initially, when we begin to feel an attraction towards someone of the opposite sex, our heart rate increases and blood levels of adrenaline and the “stress hormone” known as cortisol rise accordingly. This is then followed by the release of dopamine and serotonin, neurotransmitters that induce an intense rush of pleasure, similar to the stimulatory effects of cocaine and amphetamine.3

…The second stage in the sexual response cycle is that of excitement. It is also called the arousal phase. This is the stage where you start to sense erotic feelings and responses in your body.4

So sexual cues incite desire in the mind, which prompts the release of hormones like adrenaline, cortisol, serotonin and dopamine, which give ‘erotic feelings and responses in your body’. My experience bears this out pretty much exactly. For example, when I see a billboard featuring a woman in her underwear, if I am seriously pre-occupied, or deep in conversation, I might not register that it is a desirable image, and the cue will have no impact. But if the cue is registered in my mind as sexually desirable, then I immediately experience a mental attraction or desire – a strong sense of curiosity, if you will, which tells me that the object is valuable and important, and prompts me to look again and investigate the source of desire. If I look again, and my mind dwells on that desirable image, within about a second I experience a physical reaction: a feeling of warmth mixed with excitement flooding down into the region just above my stomach. There’s also a bit of a tightening of the chest, similar to feelings of anxiety (this is probably the adrenaline). This is sometimes followed by the feeling of muscles loosening or contracting in the groin. These changes are the beginnings of arousal, and of course feel quite good, which in turn increases motivation to dwell on the sexual cue or engage in sexual fantasy, in order to further the arousal process, and increase the good feelings.

Positive feedback loops come into play

Moreover, the symptoms of sexual arousal themselves can become their own source of sexual stimulation, thus generating a positive feedback loop.

Several body systems engage in positive feedback loops as sexual excitement increases. One example of this is vasoconstriction. The brain, in response to some initial stimulation, may tell the cardiovascular system to restrict blood flow out of the genital area. The brain then senses the resulting engorgement as a new source of sexual stimulation. This induces it to direct the veins to constrict even further to maximize the engorgement of sexual tissue.5

A friend who is a psychologist explained a similar feedback loop that was feeding my anxiety when I drank coffee. Caffeine stimulates the cardiovascular system, causing the heart rate to increase and breathing to quicken. Accelerated heart-rate and breathing are symptoms of anxiety, and the brain, perceiving these changes, is tricked into thinking that I am anxious, which then stimulates the further release of adrenaline, and anxiety sets in for real. The solution to that problem was simple: to avoid caffeine. But what are we to do when seemingly unavoidable sexual cues trigger the release of ‘arousal hormones’?

‘Arousal hormones’ decline over time

In conversation, a GP friend of mine told me that adrenaline only has a very short half-life (2 minutes), which means that any given burst of adrenaline should be 97% gone in 10 minutes. The ongoing experience of adrenaline in the body after a near-miss is the result of a person’s mind replaying the event. The continual occupation of the mind with that stressful event causes it to continually release adrenaline into the bloodstream, which is why a person can feel ‘fragile’ or ‘shaken’ for many hours after the event, even after the initial dose of adrenaline is long gone.

I theorise that whichever ‘arousal hormones’ are released into the bloodstream in response to a sexual cue should have a similar half-life. Even if these hormones last longer, they are not permanent. I theorise that the body will break down these hormones within twenty minutes to an hour, or at the very most, overnight. The time taken for feelings of arousal to subside should depend on how long the mind dwells on the sexual cue and consequently how much ‘arousal hormone’ is released into the blood stream. For example, I recently recalled a pornographic image from my past, and felt an unmistakeable burst of hormones above my stomach. The image remained in my consciousness for only a fraction of a second, and only twenty minutes later the arousal was completely gone, as far as I could feel. The important thing, then, is to prevent the mind from replaying the sexual cue, or dwelling on the symptoms of sexual arousal, either of which will perpetuate the release of arousal hormones, and further the progress of sexual arousal.

How arousal affects decision-making

The importance stopping the process of sexual arousal in the very earliest stage becomes clear when we consider that the activity of the brain’s limbic system (which deals with emotions like fear and sexual arousal, and is involved in the release of hormones like adrenaline) tends to shut down the activity of the prefrontal cortex, which ‘is responsible for higher-level cognitive functions like decision-making’.6

The limbic system operates by influencing the endocrine system and the autonomic nervous system. It is highly interconnected with the nucleus accumbens, the brain’s pleasure center, which plays a role in sexual arousal and the “high” derived from certain recreational drugs.7

…adrenaline shuts down the pre-frontal cortex, thereby inhibiting it from thinking. The body is further readied for action…One way to understand the relationship between the limbic brain and the prefrontal cortex is by way of ratio: the degree of limbic activity is usually inversely proportional to prefrontal activity. The more reactive (limbic) we are, the less we are in thinking (pre-frontal cortex) mode, and vice versa.8

So as I understand it, when the mind and body are in a state of sexual arousal, the limbic system is in full swing, which results in the shutting down of the prefrontal cortex, which is that higher part of the brain that makes decisions (Should I look at porn? Is this really a wise thing to do?). Contrary to common thought, sexual temptation is not a battle between the pleasure centre and the rational part of the mind. The rational part is already dead – it’s not even fighting. Is it any wonder that we fail to make the right decision 80% of the time?

The solution

The only reliable course of action that I have found is to turn the mind aside from even the most preliminary of sexual cues, the very instant you become aware of them. Remember that sexual cues can be physical, like a caress or accidental stimulation of the genitals, or visual, like a billboard, movie or real-life woman. They can be mental, like recalling a past sexual experience, pornographic image or sexual fantasy. I have found that the mind will often wander, seemingly at random, into thinking about sex a number of times over the course of a normal day. You need to turn away from it, and block out such thoughts immediately. There can be situational cues, like hearing the sound of the front door closing, indicating that you are home alone, or undressing to get into the shower. If there is a habit of masturbating in bed, then getting into bed or waking up in the morning can be a sexual cue. Sexual cues can be almost anything it seems, which means that becoming aware of the full range of potential sexual cues that might trigger sexual desire is important, so that we are not caught unawares.

Perhaps the most important thing to do is to become sensitive to the feeling of the very initial stages of physical arousal. As I have mentioned, I believe I can sense ‘arousal hormones’ being released into my bloodstream, which I experience as a feeling of warmth mixed with excitement flooding down into the region just above my stomach, a tightening of the chest, similar to feelings of anxiety, sometimes followed by the feeling of muscles loosening or contracting in the groin. The minute I am alert to this sensation, I immediately turn the mind away from whatever is the cause. I block it out, think about something else, and wait for the physical feelings to subside, which they usually do in twenty minutes to an hour. More detail on this process is given here.

The impact of testosterone

Unlike some other hormones (like adrenaline) which are released very quickly and subside in minutes, testosterone is much slower. It increases more gradually, and has a half-life of 2-4 hours. So to remove 97% of a testosterone boost might take around 15 hours.9

Serum testosterone levels are believed to be a significant factor in the strength of sexual drive or libido in males. Higher levels of testosterone increases sexual motivation and sexual desire.10

There will be some days or times when testosterone levels are higher than others. During those times, there may be more physical yearnings and the endocrine response to sexual cues will possibly be more intense and more easily triggered. This means that it will be harder to keep thoughts away from sex. One study shows that on the seventh day of sexual abstinence there is a temporary boost in serum testosterone levels.11 So expect day seven to be harder than day six. On the plus side, things should return to normal by day eight. Other times when an increase in testosterone might make things harder is after talking to women. Studies have shown that testosterone increases in men who engage in brief conversations with women.12 This has been borne out in my experience. In addition, testosterone levels can naturally fluctuate widely, between 10-40%.13 If there are times when you feel more easily aroused, or have physical longings, this may be a time of boosted testosterone. Ride it out, and you should be fine the next day. Or, if this is your sort of thing, take the opportunity to hit the gym. Word on the street is that higher testosterone levels help build muscle.

The “pressure” myth

One very important consideration when attempting to abstain from masturbation is the effect that abstinence has on the libido. Anecdotal accounts suggest that the longer a man goes without sex or ejaculation, the higher his sex drive will be. There is the idea that ‘sexual energy’ or ‘sexual pressure’ inevitably builds up, increasing sex drive indefinitely, and that the ‘pressure’ can only be ‘released’ by ejaculation. In reality there is probably no ‘pressure’. In the absence of ejaculation, old semen is simply broken down and reabsorbed by the body.14 If for some reason ejaculation is required for the health of the body, it seems that the body will do this spontaneously while sleeping.15 As detailed above, sexual arousal is caused by sexual cues triggering the release of hormones, rather than by the build-up of ‘pressure’. The feeling of ‘release’ upon orgasm is simply the body releasing hormones like oxytocin and prolactin into the bloodstream, which suppress arousal hormones like dopamine, and induce a feeling of relaxation and satisfaction.16 If orgasm never comes, however, arousal hormones naturally subside within the body, as discussed above, bringing a person back to baseline levels in a short period of time.

There is one uncomfortable phenomenon experienced by some men, colloquially known as ‘blue balls’, which may have lent credence to the ‘pressure’ myth. This condition sometimes occurs after an extended period of sexual arousal which does not result in ejaculation. This is not the result of a build-up of semen, however, but rather it is pain caused by the prolonged swelling of bodily tissues in the groin (testicles and prostate) which results from the increased blood flow and blood pressure to the area during arousal.17 Ejaculation will cause blood vessels to dilate, reversing this problem, but ‘blue balls’ will also resolve itself without ejaculation, assuming the state of arousal is not perpetuated indefinitely.18 The best way to deal with this problem is to avoid reaching a heightened state of arousal in the first place, or to back out of such a state as soon as one becomes aware of it. ‘Blue balls’ certainly not an inevitable result of refraining from ejaculation.

Two different playing fields

But if sexual ‘pressure’ doesn’t actually build up, why is it more difficult to abstain from masturbation after a few days without ejaculation? The first day is easy, but then it seems to get tougher and tougher. Why does temptation become more intense the longer you go without ejaculation? Surely that’s the pressure building up, making it harder to think about anything other than sex? Well, personal experience tells me that abstinence doesn’t get increasingly tougher indefinitely. It does get tougher, but it only gets progressively tougher for a week or two, before it plateaus. Rather than a continual increase in pressure, it’s more like two different playing fields.

As explained above, testosterone has a big influence on the male libido. While there is not much evidence that serum testosterone levels are affected by abstinence from ejaculation, apart from a peak on day seven, there is evidence that every ejaculation temporarily depletes androgen receptors, which means that testosterone (an androgen) does not have its usual effect on the brain. This depletion of receptors can take days to recover from.19 So if you are masturbating regularly, say once a week or more, your brain may be operating with a perpetual depletion of androgen receptors, which means that the testosterone in your blood will not be affecting your brain to its fullest capacity. The result will be a perpetually lower-than-normal sex drive. If you then stop masturbating, as your androgen receptors recover, you would expect to experience an increase in sex drive over several days until you return to a stable, celibate level of sex drive.

In a study on rats suffering from ‘sexual exhaustion’ (and thus unable to ejaculate), after a 7-day period of sexual rest the ejaculatory capacity of almost all animals increased to 4 successive ejaculations, to 5 after 10 days and to 6 after 15 days of sexual rest. Another study reported a period of 15 days for full recovery from sexual exhaustion in rats.20 There are probably differences between the recovery times of rats and humans, and it’s unlikely that someone who masturbates daily would be classed as ‘sexually exhausted’, but this suggests that there might be a medium term (1-2 week) recovery time from ejaculation in which we should expect to see a steady increase in sex drive. Note that two-thirds of the recovery occurs in the first seven days, which suggests that the most noticeable increase in sex drive will be in the earlier stages of abstinence, with the rate of increase gradually diminishing. Another study, this time on humans, showed that men who had abstained from sexual activity for three weeks showed ‘enhanced sensitivity to anticipatory cues’, and higher levels of subjective arousal when subjected to erotic stimuli than men who were sexually active.21

It seems that regular ejaculation lowers the sex drive and decreases sensitivity to sexual cues. Consequently, abstinence from masturbation is perceived as ‘pressure building up’ when in reality it is just the body and mind returning to regular, higher levels of sex drive and sensitivity. Regular, high levels of sex drive should be reached within about two weeks, whereupon they will become more or less stable. They will not increase indefinitely.

Although we don’t have to face ever-increasing ‘sexual pressure’, the higher sex drive, attained after two weeks of abstinence, is definitely harder to handle than the dulled state achieved by regular masturbation. It pays to be aware of this, and to be ready. ‘Enhanced sensitivity to anticipatory cues’ and a general increase in sex drive means that sexual cues will hit you harder and more often. You will be triggered more easily, and the bursts of ‘arousal hormones’ will be much more intense. This can actually be advantageous, however, as the burst of hormones which functions as a warning system, alerting you to turn the mind away from a sexual cue, becomes much more clear and noticeable. There is far less danger of finding yourself accidentally a long way down the path to masturbation, when the initial warning sign is so distinct. Although initially harder, it is not impossible to be sexually pure after weeks or months of abstinence from masturbation. Practice makes it a lot easier, and before long you won’t even notice it, as your mind will instinctively and automatically shut out sexual cues before they even release that burst of ‘arousal hormones’.

The Chaser Effect”

Many people who are trying to quit porn and masturbation report something known as ‘The Chaser Effect’, which is an increase in sexual urges or desire to masturbate in the days immediately after orgasm. This is in one sense counter-intuitive, because we would instead expect a person to be satisfied after orgasm. While it’s true that there may be initial, immediate satisfaction, it seems that this, in some instances, may be rather short-lived, replaced by dissatisfaction and desire. The explanation for this is that when a person encounters an abundance of something very rewarding, like food or sex, the extraordinary surge of dopamine that is released overloads the pleasure centres of the brain, causing them to prune back dopamine receptors. Following this surge, normal, everyday levels of dopamine are no longer enough to satisfy. The recent high is demanded again or the brain feels dissatisfied, as though it is lacking something.22

Why would the body do this, though? Gary Wilson explains it in this way:

Obviously, a “binge trigger” (via whatever mechanisms) is an evolutionary advantage in situations where survival is furthered by engaging in a behavior past the point of normal satiety. Think of bear gorging on high fat salmon before hibernating. Or wolves, which need to stow away up to twenty pounds of a single kill at one go. Or our ancestors, who needed to store high-quality calories as a few extra pounds for easy transport to survive hard times. Or yourself when you’re jam-packed with turkey and mashed potatoes and your favorite Thanksgiving pie appears. When our primitive brain perceives something as really valuable, it wants us to exploit the golden opportunity…fully. It can’t do that with warm, fuzzy feelings of satisfaction. Nope. It has to create feelings of lack or dissatisfaction (cravings) in order to drive us past our normal limits.23

If this is true, it would explain why people trying to recover from addiction to sexual fantasy, porn and masturbation so often fall into a serious binge if they relapse once. That was pretty common for me, at least. This behaviour may be reinforced by the idea that, ‘Since I’ve already relapsed, I might as well really enjoy myself before I get back on the wagon.’ Knowing this, we ought to be prepared to resist the urge to binge, in the event that we slip up and masturbate once.  Knowing the danger that awaits might even motivate us to not relapse in the first instance!

A further implication of the chaser effect is that the first few days of attempted abstinence, after that final orgasm, may be really tough. Until dopamine receptors recover, the brain will be crying out for more dopamine-releasing stimulation, which may lead to feelings of dissatisfaction, strong desire for orgasm or porn, and even anxiety. Hang in there. The good news is that the increased desire for masturbation or sex in the first few days after quitting might be a result of the chaser effect, rather than the recovery of sex drive as discussed in the point above. This means that these super-urges will be temporary, and should subside when dopamine receptors recover. I still maintain that sex drive after two weeks of abstinence is much higher than when one is masturbating every day or two, but it’s not as bad as the first week. Get past day three or four, and things should get easier. In addition, it stands to reason that the heavier your addiction to pornography and the more extreme the porn that you use, the more your dopamine receptors will be depleted. For heavier porn users, the chaser effect should be more significant. For only moderate porn users, or those who masturbate to fairly mild fantasies, there may be no chaser effect at all.

In a similar way to the chaser effect, I have discovered over my period of abstinence that my sex drive and urges to masturbate are significantly higher for 1-2 days after an instance of heightened sexual arousal, such as that brought on by an intense sexual dream, or accidentally viewing an explicit picture. It seems that when I become significantly aroused, for whatever reason, there is a lingering effect for a day or two, even if I immediately turn my mind to other things and shut down the arousal as usual. This is not the chaser effect per se, because there is no orgasm, although it might just be a milder version of the same mechanism – I’m not sure. Another possible explanation is that the after-effects are the result of testosterone being released during arousal, but actually the jury is still out as to whether arousal actually releases testosterone at all.24 Moreover, it is unlikely that testosterone would linger in the system for more than 15 hours. A better explanation might be that the increased sex drive and desire to masturbate after arousal is caused by the brain subconsciously dwelling on recent memories and thought patterns that the arousal evoked. Whatever the explanation, the lesson here is clear. Even if you are confident that you can shut down a heightened state of arousal without masturbating, you should still try to avoid getting aroused in the first place, because it will make the next couple of days quite uncomfortable. Or if it is unavoidable, like in the case of a sexual dream, just prepare for a tougher than usual day or two, and look forward to relief in around 48 hours.

Why it’s important to know this stuff

I have found it immeasurably easier to bring my body and mind under control now that I am aware of the processes that go on in my body and mind, and how my thoughts can influence these processes.

Specifically, it is helpful to know that sexual arousal is caused by hormones that are released in response to the mind dwelling on sexual cues, and that these hormones will naturally subside within a short period of time, providing that the mind does not continue to dwell on the sexual cue. This highlights the need to prevent the mind from dwelling on sexual thoughts, and also promises complete relief from feelings of longing simply by diverting the mind and waiting it out, without the need for ejaculation.

Specifically, it is helpful to know that the process of arousal shuts down the decision-making part of the brain, and activates positive feedback loops. This highlights the need to short-circuit the process of arousal at the very earliest stage, before it escalates and has a chance to shut down the prefrontal cortex.

Specifically, it is helpful to know that sexual tension or longing doesn’t ‘build up’ inexorably until it is ‘released’ by ejaculation. If it did, there would be no effective way to overcome sexual arousal or longing without eventually resorting to masturbation. I used to think, ‘I’m going to inevitably masturbate sooner or later, and keeping my mind pure will get increasingly harder until I do, so why not do it now, rather than later, and save myself a lot of struggle?’ Now I no longer fear the inevitable relapse. Instead I know that by controlling my mind, I can control my body.

If you have any questions at all, comment below and I will get back to you!

2Graham J. M., Desjardins C (1980) Classical conditioning: Induction of luteinizing hormone and testosterone secretion in anticipation of sexual activity. Science 210: 1039-1041.


20 Comments

  1. Cobalt says:

    Interesting conclusions.
    Particularly the part of heightened libido after overcoming the arousals strikes the right chords.

  2. Kingcooper says:

    Awesome article. Incredibly useful. Thanks so much!

  3. ManUp2013 says:

    “If there is a habit of masturbating in bed, then getting into bed or waking up in the morning can be a sexual cue.”

    I definitely have this one. Since I started nofap, I’ve had a big problem with this, I am having urges every time I lie down to sleep. Does it get better with time? What do you recommend to tackle this?

    • nofapsolideo says:

      It does get better with time. It’s basically a matter of habit and addiction. Your body and mind is accustomed to a habit, and it will take time to break it. They say that 30 days will break a habit, so it should be a lot easier after that.
      Basically, the more you do it, the more the habit will be reinforced. But the more you resist, the easier it becomes.
      So just make sure you continue to hold out when you go to sleep, and it will get easier and easier.
      It helps me to think about something non-stimulating and comforting as I go to sleep, to keep the mind off sex. If you believe in God, praying is good. Or if you don’t, maybe just mentally go through your personal goals or something, and visualise what you want to achieve with nofap or other pursuits in life.
      If you find it hard to sleep without fapping, which sometimes happens, look for other ways to relax before you attempt to sleep. Maybe read a book for half an hour, or listen to some music in a dim, quiet room.
      All the best!

  4. Hi would you mind letting me know which hosting company you’re working
    with? I’ve loaded your blog in 3 completely different web browsers and I must say this blog loads
    a lot quicker then most. Can you recommend a good webb hosting provider at a reasonable
    price? Cheers, I appreciate it!

    • nofapsolideo says:

      I just opened up a free account on wordpress.com. I don’t really know anything about hosting companies, sorry! I’m glad this blog loads up quickly though. Maybe because I don’t have any pictures? :)

  5. Stop Porn says:

    We are a group of volunteers and opening a new scheme in our
    community. Your site provided us with valuable info to work on.
    You’ve done a formidable job and our entire community will be grateful to you.

  6. james khan says:

    Very good description and superb motivational article…

  7. Dan says:

    Very helpful article man. Been praying that God will help me with this lately and just came across this great info. It, to my amazement all made sense. Especially the part where arousal shuts down the decision making parts of the brain and makes resistance near futile! Also the chaser effect and the relapse fap frenzy made great sense. I appreciate your article plenty. I’m a kind of guy who likes to know how things work. Mechanically minded etc. I’m amazed how much it helps tackling the problem once you know how your body and mind are working!

  8. Emma says:

    thanks so much., I’ll document my experience. this basic experience u shared will sure help lots of people cus it helped me.

  9. nofap says:

    thank you so much for your article……… it all makes sense to me now

  10. David says:

    Despite all dis i can’t break free 4rm masturbation.wen d sexual urges comes i find it difficult 2 avoid.It is hard.I really believe in dat pressure build up cus i discovered wen i avoid it 4 a wk i end up doing it

    • nofapsolideo says:

      Thanks for the comment David.
      You’re right, it’s not easy to keep the mind off sex when you’ve gone without masturbating for a week.
      It’s not easy, but it is possible. Learn to control your mind and your body will follow! All the best :)

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