Post Vasectomy Pain Forum

Semen Viscosity

In the marketing materials for vasectomy, you frequently read assurances that vasectomy will not affect sex in any way. One common way to reassure men is to tell them that sperm only constitute a very small percentage of the ejaculate, and that you cannot therefore detect any difference. The percentages quoted seem to vary quite a bit. I don’t have a rigorous survey of public statement for this, but my recollection is that people state numbers in the 1% to 5% range.

I found a study recently that tried to quantify this back in 1979:

Small sample size here, but you can see that the decrease in volume is 3% which agrees with what doctors are eager to claim. Indeed, this appears to be the claim the experimenters were investigating, as they conclude that:

These findings support the contention that the volume of semen originating in the testis, efferent ducts and epididymis is very small compared to the volume originating in the prostate and seminal vesicles

But what about that viscosity measurement? That’s a 31% drop. Seem a little shocking that a 3% drop in volume is creating such a large drop in viscosity? It turns out that it doesn’t take very much of change in composition to radically change the viscosity. For example, if you took the gelatin out of a cup of jello, the weight would only change by 2%, but the viscosity would drop by 99.9% I’m willing to bet good money that ejaculating jello would feel pretty different than ejaculating water, even if the volume was exactly the same.

Unsurprisingly, you do not hear doctors cheerfully reassure men that vasectomy will only decrease the viscosity of their semen by 31%. It’s hard to see how a 3% change in volume could affect the sensation of ejaculating, but one might reasonably wonder whether a 31% change in viscosity might result in a sensation that is less like ejaculating and more like urinating. In my opinion, the set of facts that men are given when deciding whether or not to get a vasectomy are not filtered in an unbiased way. Rather, there is the “correct conclusion” that vasectomy is safe and desirable, and facts that threaten this narrative have a hard time getting themselves transmitted to men who are considering whether or not to get a vasectomy.

Some men refer to semen after vasectomy as reminiscent of skim-milk, but when it comes to viscosity specifically, a more reliable comparison is the difference between cold milk and room-temperature milk, which is about 34% less viscous: (Link)


Just one study, so take it for what it’s worth. Does anyone have more science on this?


Thanks a lot for sending this link. Very useful and 100% agree with significant viscosity change. It’s the chemical composition and not the volume. I think sperm is somewhat a catalyzer and changes the semen composition significantly despite its low volume.

Post reversal I see the semen is a lot less viscous and hence flows smoother. This itself helps with the pressure drop in the pipes. Makes perfect sense mechanically speaking.

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My volume decreased by 95% and was reduced to 2 very pathetic looking drops. Felt embarrassed after I saw surprise on her face. I lost that rush and intensity that use to come from orgasm altogether, and whatever I produced was very sickly, very thick, and glue-like looking. Half of the time I wasn’t sure if I had orgasm or not, very anti climatic.

I have had some improvements after reversal, volume is steadily increasing, looks milky-white now.

Orgasms are still not as pleasurable as pre reversal, but enjoyable nevertheless. If only I could get rid of the pain, I’d be very happy.


Ironically after reversal I feel my volume has dropped. The fluid is less viscous and thinner but volume is nowhere near four years ago. I hope it will keep improving but not sure, we’ll see. Overall the viscosity argument in the paper Ethan sent makes sense to me. However while viscosity has to do with the flow in the pipes I think sensation and orgasm is beyond just how smoothly the fluid flow smoothness is. It is likely related to how the nerves work down there. I’m awaiting for the reversal impact to get better so that I can gauge the neurological changes there. Hard to imagine what will happen, but I hope we all improve with time.

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I did not experienced a reduction in volume but the viscosity was reduced significantly. Ejaculate appeared very milky and watery. Orgasm was almost not existing and almost felt like the sensation when scratching an itch. After my reversal the appearance of my semen improved and is back to pre vasectomy. Orgasm is normal again but do take what is feeling like forever to achviece during sex. I still suffer from pain in my left testicle from time to time and urologist recommend removing the epididymis but after doing some research I refused - just have to live with pain meds and regular ejaculation which also seems to help.


Weird how it affected men in different ways. Can relate to non existence of orgasms. As basic as it sounds, it was horrible to live without that release.

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It ruin you emotionally and physically not to speak of the stress on your marriage.


Totally agree and I am still suffering emotionally years later let alone physically


Honestly so far reversal and ejaculation is slightly improved for me post reversal however I don’t think I’m nowhere close to where I expect to be. I don’t want to digress from the topic though …

I’m meeting with PK tomorrow to discuss SA first time - I have semen sample last week for the first time after reversal. I’m awaiting the discussion to see what he says.

I expect another six months before I feel more normal I guess.

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Doctors state there is no differece noticeable pre and post vas considering semen ejaculate. But we can all confirm that is a lie. I rembember a very noticeable difference in odor. The post vas semen was odorless while semen after reversal had a touch of bitter in it. My post reversal semen is a bit lumpy it’s not smooth in the way it used to be. I think it has something to do with formation of macrophage debris due to macrophages invading sperm cells. Doctor told us bs and they will continue doing so, cherry picking and selling vas. Standing by their Hypocritic oath (or whatever they swore)

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I’m convinced that vasectomy causes some kind of prostate dysfunction for some guys. There are so many stories that feature prostate pain, weak urination, reduced ejaculate volume, glue-like semen, strange odors, penile pain (which can be caused by prostate), boggy prostate and that recent Netherlands study confirming that there is a small increase in prostate cancer risk.

Something is negatively impacting the prostate somehow – it’s not getting some kind of substance or signal or … something … that it normally gets. Or the prostate is maybe getting some friendly fire from the immune system. Some guys have mentioned a possible neural pathway that is disrupted that is supposed to link up the prostate and the testes.

The body is just so complicated. Lots of things are connected to lots of other things in surprising ways. It really is a cartoon that we are sold by urologists who describe it as simply obstructing sperm with no side effects.

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All of the above here

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Yeah I’ve noticed difference too. It’s less chunky and more watery post vas. It doesn’t smell the same either. Sensation wise I can only blame testicular pain and congestion which I think is masking any difference due to viscosity.

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I will add that it may be getting signals that it shouldn’t be as well (nerves). We’ve seen some men that had good numbers, poor numbers or azoospermia post reversal that report their symptoms cleared up immediately or eventually. Some claim their symptoms improved shortly down the road, or eventually.

I have personally experienced a wide array of such symptoms in the past post vas and post reversal. I even experienced some stuff down the road post redo reversal that I never experienced prior to it. My guess is that I experienced many different triggers over time and sometimes they were simultaneously. I suppose I am lucky that my symptoms cleared up eventually. I generally don’t experience anything worth writing home about anymore.

When I was fertile and had great numbers, my semen wasn’t as thick. It was generally thinner, more milky, with some globbyness to it. It was more like what I remember as normal. When my redo reversal failed, I definitely remember doing an SA after ~72 hours of abstaining and blowing significantly less volume into the cup.

At this point, there are few posters in this thread, and look at the difference in between what we experienced as individuals. In some cases, we experienced the opposite of one another and something tells me this trend will continue. Very interesting stuff :thinking:

I totally agree.

Yep, and the same could be said in regard to “they just snip the tiny tubes down there”. That seems to be another very common misconception. “Urologist’s disconnect your testicles from the end organ - the penis”. That would be a more honest and revealing statement. Somehow these memes and others seem to be running down the same pipeline of disinformation :roll_eyes:

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Yeah in retrospect the whole idea of cutting a tube in your body seems insane. I can’t think of any other organ, tube, vein, etc. that you would electively disconnect and not expect problems or death. In some sense the whole reason you exist is to shoot your DNA out that tube. It’s really a problem that society regards a vas as safe. How did that ever come to pass?

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in retrospect the whole idea of cutting a tube in your body seems insane.

My thoughts exactly. And size means nothing. The bile duct, the median aperture in your brain, the vas deferens… All about 4mm wide. Obstruct them at your peril.

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My answer would be - through intentional and accidental social programing Through intentional and accidental social engineering, etc. It works something like - the assumed wrong information that keeps on giving.

If the powers that be thought we as humanity should assume otherwise, or thought we should be given a proper warning beforehand, we as humanity would be receiving such information from the proper authorities.

IMHO, overpopulation is the biggest reason that the truth about vasectomies is kept out of sight out of mind. Start researching from the top of the pyramid downward. The BS starts at the top.

Just my opinion.

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I dunno Ringo that sounds like a vast conspiracy and I just don’t think our institutions are up to the task. Though I could be swayed if you have sources. I tend to think it’s a follow the money problem. Only urologists study pvps and they’d be pariahs for exposing the danger in a very lucrative procedure. Even places like pur clinic speak guardedly on the issue in their published media.

Like I said, just my opinion based on nearly a decade of research. Follow the money is just part of it, and that’s more like mid pyramid.

I have been following the doc’s you mentioned and several others for nearly a decade too. What have they changed about any of what I am addressing? How have their contributions effected the big picture? I will not elaborate.

On a side note, do you know the origin of the term conspiracy theory? Don’t answer that.

I’m thinking this discussion would be better in a thread of it’s own. If anyone feels the urge, by all means, please start one.

Let’s get back on topic.

Onto the topic of viscosity. I haven’t ever noticed a difference from my vasectomy. Which I was very curious of prior. It is more effected by diet and frequency of orgasm. I used to take a zinc supplement to increase volume and intensity of orgasms, back in the golden days. Also LOTS of water and a really healthy diet helped semen viscosity. I dont take zinc today as it aides in sperm production as well and I am in the process of trying to kill all the sperm in my body.

I did not have pain for the first 4/5 years of my vasectomy. So lots of vasectomy orgasms on zinc supplements.

As far as no sensation from orgasm. Some can be great, half or less of my orgasms can fizzle, or have little sensation, but I never attributed it to my vasectomy. Usually its the timing of my kegle’s or prostate “pumps” during orgasm. I know sometimes I will ‘miss a beat’ and then my orgasm is alright, or not so sensational.

My primary issue is pain in left testicle. Figured some other data might help.

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