People have been selling products that promise to increase semen volume for centuries. Now is as good a time as any to take a moment and ask ourselves: Why?
Let's start by making sure we're all on the same page. Semen, also called seminal fluid, and sometimes incorrectly referred to as sperm (incorrect because sperm is in semen, but makes up only about 1% of it) is the fluid that is expelled from the penis during ejaculation. Most (but not all) men ejaculate when they orgasm, and most of the time some semen comes out. How much semen a man ejaculates depends on several factors, mostly individual difference. A 2010 World Health Organization study which looked at semen volume across the globe put the range (including fertile and infertile men) anywhere from 0.8 milliliters to 7.6 milliliters, and the average is between 3 and 5 milliliters. (For a point of reference, a teaspoon is 5 milliliters.) The amount of semen a man ejaculates will change as he ages, with peak semen volume produced in ages 30-35 and volume being lowest once men reach 55 years and older.
Semen is also a body fluid with a lot of baggage. While most of us are conditioned to want to reduce the amount of fluid that comes out of our bodies (from our pores, our noses, our eyes, our vaginas) semen is, apparently, something men should want more and more of.
Why Increase Semen Volume?
It's hard to know which came first, the product or the desire. Was some guy sitting around thinking to himself, wow, I wish I ejaculated more? Was it the first time that guy's partner said to him, "Gee, you don't ejaculate nearly as much as the last guy ejaculated. What's with you?" Or did some enterprising individual realize that there was a market in exploiting men's insecurities about sex? Probably the most likely explanation is that semen volume was associated with fertility (which is both true and not true; see below) and men who wanted to have more offspring, especially male offspring, were promised a better chance if they had more semen.
Today, the dozens of companies making unfounded claims about their semen-volume-increasing pills seem to focus on three reasons why men should care enough to buy their products: more semen makes you more masculine, more semen increases your sexual pleasure, and more semen can make you more fertile. Let's consider each of these claims.
Semen Volume and Masculinity
Most of the websites that push semen-volumizing products tell you that more ejaculate will make you feel more virile, more like a man (with a not so subtle nod to male porn stars). In some ways this is a perfect pitch because there is no way to prove it. Feeling masculine is a cognitive response; it isn't tied directly to biology. We know there is great variation in semen volume. Someone who ejaculates half a teaspoon may feel very masculine, and someone who ejaculates a lot more may not feel masculine at all. Simply put, we are the ones who give meaning to how much we ejaculate. Not surprisingly, no scientist has really put this idea to the test; we don't really know how many men even think about semen volume and how it impacts their sense of themselves as masculine or their enjoyment of sex.
Increase Your Semen Volume, Increase Your Sexual Pleasure?
This one is a bit easier. There is absolutely nothing to suggest that there is a relationship between volume of ejaculate and sexual pleasure. The virtual salespeople suggest that having more semen means your orgasms will last longer and feel more powerful. These claims are unfounded and highly unlikely. There aren't a lot of nerve endings in the tubes that the semen passes through as it leaves the penis, so it's near impossible to know if men are even feeling the fluid as much as they are feeling the involuntary muscular contractions that are part of ejaculation and move the semen out of the body. The picture they are painting is one of prolonging orgasms for minutes while a steady stream of ejaculate pours forth from your penis. It's a funny image, but more cartoon-funny than real-life-funny.
Semen Volume and Fertility
Most popular writing on semen volume confuses sperm density with overall volume. Sperm density refers to how much sperm is in semen -- the higher the density, the more sperm there is in the semen. Semen volume refers to the total amount of fluid. The relationship between volume and density is one area where there has been a lot of very good scientific research, conducted mostly in the context of fertility. For fertile men with good sperm counts, more semen volume does mean more sperm (because it means more everything). But if a man has a low sperm density, then even if he were able to increase the volume of semen, it may not have any influence on the amount of sperm in the semen, or the likelihood that he could impregnate a partner. The bottom line is that the relationship between fertility and semen volume is not always the same, and if a man is concerned about fertility issues the best thing to do is start with a doctor, not try unproven Internet pills.
Is It Possible to Increase Semen Volume?
This is the $160-for-a-three-month-supply question: Do any of these semen volume increasing pills work? The easy answer is probably not. There's been no published, peer reviewed clinical research to suggest that they do. Many companies refer to research, but when you follow it up you find the research isn't with their product, and is often in an entirely different context. Distorting actual research to suggest that their products work tends to reduce the credibility of these companies. As a sexual health educator I recommend people stay away from these products as they may be, at best, a waste of money, and at worst, harmful.
The more complicated answer is to say that they might work, depending on what you expect them to do. It's possible that there is a placebo effect of taking these pills, that a man will absolutely believe that he's got more ejaculate than before, and feel more manly because of it. Measuring semen volume is much more difficult than you might imagine, and in the absence of any unbiased research, you'd have to take the companies' word for it, which probably isn't the best bet. There has been some research on what does and doesn't impact semen volume. Most of the research that goes looking for impacts find that while illnesses, treatments for illness, and exposure to chemicals can have a huge impact on fertility, they don't have as significant an impact on overall semen volume.
It's probably true that staying hydrated will maximize your semen volume (although that's not the same thing as saying you'll have more than "normal"). At least one study documented that going 2 to 3 days between ejaculations results in more volume. But that same study noted that waiting longer (4 to 6 days) doesn't increase the volume.
What About Ejaculation In Porn?
So howcome all those porn stars seem to be ejaculating in heaps and not teaspoons? There are a few answers to this question. First, there's the magic of camera angles, close ups, and the fact that actors physically manipulate the semen to spread it out, and make it seem more voluminous. Also remember that there is a huge variation in semen volume, and some men have four or five times the volume of other men. Sometimes those men end up making porn. In the end, porn isn't a good measure of real sex and this is true for semen volume as well.
Cooper, T.G., Noonan, E., Eckardstein, S., et al. "World Health Organization Reference Values for Human Semen Characteristics" Human Reproduction Update Vol.16, No.3 (2010) 231–245.
Elzanaty, S., Malm, J., & Giwercman, A. "Duration of Sexual Abstinence: Epididymal and Accessory Sex Gland Secretions and their Relationship to Sperm Motility" Human Reproduction Vol .20, No. 1 (2005): 221–225.
Levitas, E., Lunenfeld, E., Weisz, N., et. al. "Relationship Between Age and Semen Parameters in Men with Normal Sperm Concentration: Analysis of 6022 Semen Samples" Andrologia. Vol. 39, No. 2 (2007): 45-50.