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Why Do Men Feel Sleepy After Sex? Prolactin, Oxytocin, Vasopressin, et al.

After sex it is very common for men to feel tired or even fall asleep on their partners. There are a set of specific reasons as to why this tiredness occurs. In most cases it is a combination of exerting a lot of physical energy during sex as well as the chemicals that are released when the act is complete and orgasm is achieved. In the article that I wrote regarding anxiety – I listed that one of the best cures is sex – and that’s because it takes away stress and in order to achieve orgasm, it is said that a person needs to let go of all fear. Although not every man will feel tired after sex, most do report feeling more relaxed.

Why do men feel sleepy after sex and ejaculation?

1. Prolactin

When a man orgasms, prolactin is released – a hormone that is linked to feelings of sexual satisfaction. The primary reason a man feels tired after sex is due to the fact that prolactin causes sleepiness and drowsiness. During sleep people have higher levels of prolactin. In studies involving prolactin injections into animals, they became tired immediately.

The reason a man cannot simply go for another round immediately after having sex has to do with the fact that their prolactin levels are very high. When the prolactin levels dip again, the man will be ready for another round. There is a relationship between prolactin and dopamine – increased dopamine can act as a prolactin inhibitor. Some research has demonstrated a link between prolactin-deficiency and fast recovery times after sex.

It should also be noted that prolactin levels after orgasm during sex are 4X higher than those after masturbation. So masturbation in general is not going to make you feel nearly as tired as a full blown sex session.

2. Oxytocin

This is sometimes referred to as the “love hormone” because it promotes bonding between partners. In general it promotes love and trust of people that are intimate with each other and can also cause increased social relaxation. The fact that people feel more relaxed around each other eliminates most fear and anxiety (both stimulants). Because the body is nearly void of natural stimulants and stress after sex, people are naturally going to feel tired and in lounge mode.

3. Vasopressin

Vasopressin has been linked to cerebral tiredness. It is a hormone that primarily helps constrict blood vessels and control water retention. It plays a vital role in helping our body regulate homeostasis and plays a role in sex and social behavior. It increases our ability to bond and can reduce stress. Although it is a fairly complex hormone, the fact that it may be released directly into the brain after sex is thought to help increase the relaxation along with oxytocin.

Source: http://www.ncbi.nlm.nih.gov/pubmed/4145418

4. Neurotransmitters

During ejaculation, men release norepinephrine, serotonin, and NO (Nitric Oxide). It is the combination of different chemicals and neurotransmitters that are released into the system that leads to relaxation. There are more than these three released of course, but these are some of the more common neurotransmitters that are released. Serotonin is known to have a calming effect on the brain as well as the body. Nitric oxide is released by the prostate gland and basically promotes relaxation throughout the entire penis.

5. Parasympathetic Relaxation

After sex, the parasympathetic nervous system takes over and the sympathetic is put to rest. Parasympathetic responses promote physical relaxation, blood flow to the extremities, and calmness. In order to reach orgasm, it has been reported that a man must have no fear or let go of all stress. The combination of relaxing chemicals and neurotransmitters override the production of epinephrine and reduce dopamine (a stimulating neurotransmitter) after orgasm. Plus the act of being intimate with another person really helps to further reduce anxiety. If your fight or flight response is literally shut down during orgasm, it is no wonder that you feel a little more tired than usual.

6. Physical Exertion

Usually the man is the one doing more work physically while having sex in comparison to the woman. Women typically don’t have to do much other than lay back or go for a ride so to speak. It is the man that does the thrusting and if the sex session lasts awhile, he may end up getting pretty tired by the time things come to an end. Some partners have sex for over an hour and when a man is doing a lot of physical work to please his partner, he gets tired.

7. Sex at Night

Most people have sex towards the end of the day or at night and after a long day already, it is pretty natural to feel tired. One last “bang” before the night ends is what does it for most men – especially if the sex is very late at night. It is natural to feel tired at night, and after orgasm, it’s a double whammy of tiredness from the hormones, chemicals, and neurotransmitters that flood the body and brain. Your best bet at this point is to just chalk it up and get a good night’s sleep. Sex can be one heck of a good remedy for insomnia if done at an appropriate time at night.

How to combat the post sex sleepiness?

If you feel tired after sex, probably the best thing you could do for yourself is give into sleeping. If it is at night, you probably don’t care and are going to sleep anyways, but if it’s in the afternoon, you may want to consider taking a nap. If you don’t want to take a nap, you could always make sure that you have some sort of stimulant around like caffeine. Go grab a cup of coffee or make yourself go do something.

Really the only other way to combat post sex tiredness is to lower your levels of prolactin. Probably the best way to counteract high prolactin levels is with some sort of stimulant that increases dopamine. Dopamine levels keep increasing until orgasm, and then the prolactin takes over. It’s best though to simply rest for awhile before having another sex session – who doesn’t like the satisfaction from the prolactin being released – it feels great.

Note: Many scientists believe it is a natural evolutionary response to feel sleepy after sex for men. It is hypothesized that the prolactin helps prevent a man from running off with another partner, or hopping to another woman’s bed.

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{ 33 comments… add one }
  • Tiffany April 18, 2018, 2:42 pm

    Every time I let my husband have anal, he seems to be even more sleepy. I can’t imagine why this would make him more tired. I was riding him reverse cowboy doing anal last week and after finished I keep going because I hadn’t went yet. And he fell asleep!

    Why can’t guys go as long with anal? Now all I got out of it was a sore ass and no release. He likes it when I play with his balls when I’m riding him reverse cowboy anal, but I think that might be leading to him going early. Thoughts?

    • Jim September 5, 2018, 7:14 am

      A lot of imagery there. I have many thoughts. But yes, I suppose playing with his balls makes him release faster.

  • Cindy January 10, 2016, 4:57 pm

    So what happens when your man falls asleep on you after a BJ, but while he’s still fingering you? What about that???

    • Gina June 28, 2016, 8:46 pm

      Make sure you orgasm first so he won’t get sleepy. My man gets too tired if he orgasms first. If your man is smart, he knows woman orgasming first = wild on top riding time and oral.

  • drew December 12, 2015, 1:51 pm

    Comparing caffeine to methamphetamine, you really have never had amphetamine of any kind.

  • Derek July 4, 2015, 5:35 pm

    Never been much of a sleeper after sex. When my wife and I didn’t have kids we would do it 6 or 7 times a day on average. Now in our 30s and 4 kids we average once a day at the least. Afterwards I wait around to be able to sleep and would do another round if she wasn’t already asleep. Maybe I’m missing out on this whole prolactin buzz.

    • fred October 10, 2015, 10:03 pm

      BULLSH*T! 6-7 times a day every day on average?! Do you realize how stupid that sounds or what “on average” means?

  • lace April 6, 2015, 2:20 am

    The part where the guy does most of the physical work is not always true. “Going for a ride” can be a lot of work. I would say on average, I do most of the work. My point being – in the past, I think my sexual relations did involve the guy doing most of the work, but it doesn’t have to be like that. Women – it is really empowering to take the lead and feels amazing. Men – let go of the control and let your lady take you for a ride. You won’t regret it.

    • fred October 10, 2015, 10:01 pm

      I agree. I’m a man and was surprised by that statement. Yes, once it comes to that point I start to feel tired after a while of pumping but up to that point she’s blowing me, licking me and we’re in 6 different positions before I’m blowing my load. I also disagree with the masturbation part. I sometimes feel worse after I jerk-off than I do after sex. Oh, and forget about a good blowjob, she blew me so good once I went into such a deep sleep, she literally thought I died! I woke up to her shaking me and screaming my name… LOL!

  • Tami January 24, 2015, 8:50 pm

    My man is snoring right now after some good head. He has been stressed all day and I’m pregnant so I’m not feeling very intimate lately. Afterwards it’s like all that stress was totally gone and he looked so happy, smiley and calm. So I going to let him sleep and go make food for when he wakes up.

    • Sirk March 22, 2015, 8:44 pm

      You’re a good woman Tami.

  • ToughLove November 12, 2014, 3:02 am

    Well I used to fall asleep right after sex some years back but then noticed that I have stopped falling asleep since I am practicing Zazen/meditation. I don’t know what is going on inside me, but I feel as fresh as before I started the sex. I hope my experience would help other guys to cope up with this sleepy problem. :)

  • Dre November 9, 2014, 8:14 pm

    I really like the Prolactin release, that sh#t is DOPE! yes it makes you really sleep, but I can fight off the urge of sleep and just enjoy it. However, some can’t! My Partner, who is also a man, 6 foot 3 and big / strong kinda resembles an action man. HOWEVER, he becomes a big baby after an orgasm and just drifts off to sleep. Try and wake up the big baby up, he moans “leave me,” “you took it out of me.” I be like – b**ch please, we got S**T to do today!

    Anyway, the scientific statement that increasing dopamine levels right after sex can and will decrease Prolactin levels within the body, making the individual less sleepy, works! I used the big baby as a guinea pig. Ladies the smartphone may be the answer! The light that a smartphone gives off is similar to these certain UV rays the sun gives off. The human eye detects these rays and uses them to begin waking the body up. I think its called blue light or something like this, don’t know the full scientific explanation for it.

    So combine the smartphone’s light and entertainment usually something boring to do with sport or more exciting games! It worked! As much as it pains me to say it… as I hate this game – Candy Crush was the solution! After sex I put his screen on bright and told the him to play ONE and ONE game of candy crush. It worked… didn’t feel tired at all as he loves the game (dopamine) and the light from the phone kept him attentive.

    Try it out accordingly if you think it would suit your relationship. Obviously don’t let the MOFO keep playing, while he’s playing freshen up and then get to F**KING again or whatever it is your doing. One Love X

    • Peter November 16, 2014, 4:08 am

      For me that doesn’t work at all. I could be outside in the sun working and it would not matter. If I don’t take a nap I’ll feel sleepy until I do, no matter what. There seems to be a correlation between the frequency of sex and how sleepy I get (less often, more sleepy). Today I had sex around 2pm and I was feeling very sleepy until I couldn’t hold it back. Around 7pm I had to take nap. I got to the point that I was falling asleep in the chair. Three hours later I was able to wake up… Now I’ll have a hard time falling back asleep — this sucks.

  • girlwhosguyfallasleep November 8, 2014, 1:48 pm

    My boyfriend falls asleep immediately after 2 hours of sex. Takes him like 2 hours at most to ejaculate. But even if it takes 30 minutes, he falls asleep. Now I know why. Try to wake him? There is no way I can wake him. I usually take this chance to do other stuff while he recuperates.

  • Sam Miheso June 22, 2014, 9:34 am

    And for how long is it supposed to take before the 2nd roud? And a normal sex is to last for how long while having sex?

    • Ven June 25, 2014, 2:58 am

      LOL!!! Sex is sex. It depends how strong you are and how you deal with it in action. Actually, men do a lot of work before cumming to his girl/partner. While the girl just needs to adjust to what position suits her as that’s her hobby. They just need to talk and go on

  • bowchicawowow May 18, 2014, 1:51 am

    Really irritated at the fact that most articles I find are in regards to “Why MEN” become sleepy after an orgasm. I want TO FALL ASLEEP after an orgasm. Women do it too and to hell with these cultural biases as if to imply that women just want to cuddle and talk after sex. I’m a women who doesn’t want to cuddle and talk after sex. What are we going to talk about the big mystery to the meaning of life? His thoughts don’t need to go beyond the bedroom at that point. If I’m pleased he just served his life purpose. There ya go mystery sovled!

    • GLOOM May 20, 2014, 2:53 pm

      No need to feel irritated… It is scientifically proven that men feel tired after sex… it’s a natural response. Women do not have the same response. Obviously it is possible for women to also feel tired after sex – especially if it lasts awhile and/or they exert a lot of energy. However, just because you feel tired after sex does not mean your body elicits the same biological response as men.

    • Eiad June 4, 2014, 6:17 pm

      Lol angry feminist. Sorry… it’s just funny.

      • Jim September 5, 2018, 7:20 am

        Don’t you know it’s sexist for men to have a penis and ejaculate?

    • Brian June 21, 2016, 1:16 am


  • TwiceNightly April 29, 2014, 4:19 pm

    This happens to me. I do it with my girl at least twice every time I see her. I’d like to stay awake longer and do it several times more but I’m snoring by midnight. If I see her in the day and need to drive somewhere I’m almost falling asleep at the wheel. Ordinarily if I don’t have sex I have enough energy to be up all night but not when sex is involved. Bain of my existence

  • manny March 30, 2014, 5:58 am

    after 1 orgasm im so tired I can’t move for at least 5 mins

  • Todd Wiseman March 17, 2014, 2:57 am

    only a un-educated fooL drink that ”red buLL crap” that level of caffeine is equal to using cocaine, i sure wish the fed government would ban all those fake azz energy caffeine pills , they are allowing a whole new generation of addicts, under the microscope there is very little difference between caffeine and methamphetamine. please drink something healthy , like milk or grape juice, or caf free pepsi cola.

    • josh June 6, 2014, 11:15 pm

      “…something healthy like MILK… pepsi cola.”

      Are you f’ken serious?

    • Jason November 12, 2014, 8:10 am

      Please tell me you’re joking. 1) You cannot see caffeine under a microscope. Maybe through X-Ray Crystallography, but not a microscope. Secondly, you have absolutely no knowledge on the structure of either molecule. Amphetamine is a Phenyl Group connected to a 3 carbon (propyl) chain. On the 2nd carbon, there is a secondary amine (An NH2 connected to a CH3) group. Caffeine on the other hand is more closely related in structure to Xanthine. Xanthine is one of the precursors biochemically in your brain to Adenine and Guanine. Your comparison of the two is like comparing a jet plane to a car. Yes, they both transport people places; however, the pharmacologies are completely different. Also, all of the drinks you listed are not exactly the most healthy either. Pepsi is absolutely garbage for you, grape juice is empty calories, and milk is honestly not the healthiest thing either. You’re better off sticking with green tea, water, etc.

      Source: I’m a medical student.

    • raul dcosta March 17, 2015, 4:26 pm

      You just got burnt by Jason. Medics on the way ;)

    • Lost_buoy March 3, 2016, 9:57 pm

      Only an educated fool could write so poorly, and also be so massively misinformed. Red bull & cocaine? no. Caffeine & meth? no.

    • Buzz Lightyear February 10, 2017, 8:26 pm

      Thank you, Todd for the stupidest comment I have seen in a long time! I laughed, I cried, I pooped my pants. A+ material

  • gwajo March 15, 2014, 3:54 pm

    I fall fast asleep as soon as come, I even had red bulls and play boosters but nothing helps. How can someone refrain from sleeping after the first round? I don’t mind the second one. I’m sure my baby thinks I’m weak because she older than me.

  • Ryan Oliver Dakura January 19, 2014, 9:02 pm

    I dont feel sleepy at all i can work right away,if i have a active partner i can have another one nd i prefer working hard as if nothing ever happened,what is wrong wth me.

    • GLOOM February 27, 2014, 2:43 am

      Nothing is wrong with you. Not everyone feels sleepy after sex.

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