Specific behaviors involving a man’s ejaculated semen may be considered erotic to some, but unappealing to others. Such behaviors may include ejaculating onto a partner’s face during sex (a motif in pornography commonly referred to as a “facial”), or into a partner’s mouth. In the latter case, which may arise during fellatio if the penis is not withdrawn from the mouth at the point of orgasm, the giving partner may choose to spit the semen out, or to swallow it. The choice is ultimately a personal one, but with safe sex practices, communication with your partner, and experimentation, you may discover your own opinions about swallowing ejaculate.
Can I Really Swallow It?
Yes, but before you do, or before you engage in fellatio, we recommend that you and your partner both get tested for sexually transmitted infections (STIs). If you or your partner have not been tested, we also recommend using barriers for oral sex and abstaining from making contact with ejaculate.
Semen is mostly water.(1) Semen also contains amino acids and protein, sugars such as fructose and glucose, minerals such as zinc and calcium, vitamin C, and a few other nutrients. (2) Sperm cells themselves make up less than one percent of semen* and are not present for men who have had a vasectomy. Semen is edible, and if swallowed, will travel down the esophagus and into the stomach, where it will be digested in the same way that food is.
Typical nutritional content of human semen. Serving size is large to show trace components.
For sources, see 1,2,16,17,18,19,20,21,22
Some people have gone as far as to make cookbooks and cocktail recipes incorporating semen as an ingredient, but others complain that swallowing semen can give them an upset stomach. In rare cases, a person may discover that they have an allergy to the proteins found in semen: a condition known as seminal plasma hypersensitivity.(7)
*While the testes may contribute up to five percent of the total ejaculate by volume (3), this includes fluid that surrounds the sperm cells. We may calculate how much of the semen is actually made up of sperm cells by assuming a spermatozoon volume of 2.22 × 10-11 ml (4), a semen density of 1g/ml (5), and spermatozoon number density no higher than 375 million /ml. (6) We assume spermatozoon density comparable to water (1g/ml), which makes our one percent figure valid both by mass and by volume.
What does It Taste Like?
The taste of semen may vary widely. Semen’s alkaline quality may give it a bitter taste. That it contains sugars such as fructose lends support to a sweet taste. (A high sugar content is also common to ejaculate produced by men with diabetes.8) That it contains zinc also supports claims to a metallic taste, while some people claim that semen tastes salty. Based on anecdotal evidence, one may expect to find the taste of semen anywhere from enjoyable to tasteless to disgusting. There’s really only one way to find out; men may also sample their own semen if they are curious!
The primary way of controlling the taste of semen is through diet. Recommendations may focus on certain foods, but the best way to optimize the taste is to experiment: Keep track of diet, and, if the man isn’t sampling his own semen, communicate with your partner about when it tastes better or worse.
Some recommendations for sweetening the taste of semen include eating or drinking things with high sugar content such as fruits - pineapple in particular, or fruit juices. Other suggestions for improving semen palatability include reducing meat consumption or ingesting cinnamon, lemon, or green tea. Some products and supplements are specifically marketed to improve the taste of semen when consumed, but as with all dietary recommendations listed here, your own experience may differ. Finally, one could also use a sweetened lubricant to try to mask the taste of the semen, or wear a flavored condom so there is no contact with the semen at all.
What about Volume and Consistency?
The average volume of semen produced at ejaculation is two to five milliliters.6 For reference, that’s roughly the volume of two to seven Skittles (about 1.5 and 5 ml respectively). Generally, the volume of ejaculate will increase with the time since last ejaculation (up to some maximum) and with proper hydration.
If it was recently ejaculated, you may expect semen to be a body-temperature, coagulated fluid, with the viscosity of a heavier grade, room-temperature motor oil and with the density of milk.*
*For more about the physical characteristics of semen, you may wish to read the full article.
Does Swallowing Semen Really have Health Benefits?
Numerous sources claim that ingesting semen has health benefits, however most of these “benefits” come from myths and misinterpretations of scientific studies.
Some urban legends involving semen have claimed it as an effective teeth whitener (likely arising from the fact that semen contains relatively high levels of zinc), a good source of protein (at most 1/20th of ejaculate is protein by mass), or a healthy nutrition supplement. Semen does not whiten teeth, and unless consumed in copious amounts, it is unlikely that ingesting semen will have any effect on dietary health. For those concerned, a typical ejaculate will contain only one or two Calories* and less than half a gram of protein.2
One oft-cited study, conducted in 2002, suggested that semen may act as an anti-depressant when absorbed within the vagina,9 while others have linked seminal exposure to decreased risk of breast cancer10,11 and better health in general for heterosexual women.12 A hasty interpretation of these findings should be cautioned against:
These and many similar studies relied on statistical correlations between survey answers, using different methods of contraception as a proxy for semen exposure, and limited their analysis to heterosexual coitus. Alternative causal factors beyond the properties of semen itself have been proposed, as many women who do not use condoms during intercourse may be in more satisfying, long-term relationships, may use alternative contraception, or may receive more satisfying sexual stimulation and achieve better orgasms.12
As for the experience of homosexual men, who may also regularly be exposed to and swallow semen, yet have statistically higher rates of depression, one study suggested that explanations of any anti-depressant effects of semen might have to be exclusive to females.12 Such a constraint should at least encourage our skepticism regarding the anti-depressant qualities of semen.
One final claim with a bit more scientific support is that exposure to the father’s semen during natural pregnancy may benefit the success of the pregnancy by conditioning the mother’s immune system to better tolerate the conceptus.13,14 It has been claimed that this might extend to swallowing semen, however further research is needed to demonstrate the oral absorption of seminal components into the mother’s blood.14
In conclusion, with a possible exception for couples who have recently conceived, any health benefits that arise from swallowing semen are most likely entirely psychological effects, or are at least better associated with the health benefits of sex in general.
*Many sources give higher counts for a single ejaculate in the range of 5-20 Calories, but we may simply consider that for this to be the case, semen would have to be a few times more energy-dense then whole milk (which it certainly is not). Calculating the caloric content of semen due to macronutrients, as Tracie Morrissey has done15 and incorporating the small contributions from organic acids still gives a figure of only ~0.8 Calories for a typical 3.4 ml ejaculate.
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2. Owen, Derek H., and David F. Katz. “A Review of the Physical and Chemical Properties of Human Semen and the Formulation of a Semen Simulant”. Journal of Andrology 26.4 (2005): 459-469. Web. 6 Feb. 2015. DOI: 10.2164/jandrol.04104
3. Dawson, Chris. “Semen and Sperm Quality”. Netdoctor.co.uk. 2015. Web. 6 Feb. 2015. <http://www.netdoctor.co.uk/menshealth/facts/semenandsperm.htm>
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9. Gallup Jr., Gordon G., Rebecca L. Burch, and Steven M. Platek. “Does Semen have Antidepressant Properties?” Archives of Sexual Behavior 31.3 (2002): 289-293. Web. 6 Feb. 2015.
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11. Lê, Monique G., Annie Bachelot, and Catherine Hill. “Characteristics of Reproductive Life and Risk of Breast Cancer in a Case-Control Study of Young Nulliparous Women”. Journal of Clinical Epidemiology 42.12 (1989): 1227-1233. Web. 7 Feb. 2015.
12. Brody, Stuart. "The Relative Health Benefits of Different Sexual Activities." The Journal of Sexual Medicine 7.4pt1 (2010): 1336-361. Web. 7 Feb. 2015.
13. Tremellen, K. P. “The Effect Of Intercourse On Pregnancy Rates During Assisted Human Reproduction”. Human Reproduction 15.12 (2000): 2653-2658. Web. 6 Feb. 2015.
14. Koelman, Carin A., Audrey B.C. Coumans, Hans W. Nijman, Ilias I.N. Doxiadis, Gustaaf A. Dekker, and Frans H.J. Claas. "Correlation between Oral Sex and a Low Incidence of Preeclampsia: A Role for Soluble HLA in Seminal Fluid?" Journal of Reproductive Immunology 46.2 (2000): 155-66. Web. 7 Feb. 2015.
15. Morrissey, Tracie Egan. "A Complete Breakdown of the Nutritional Content of Semen."Jezebel. 8 Aug. 2013. Web. 6 Feb. 2015. <http://jezebel.com/a-complete-breakdown-of-the-nutritional-content-of-se....
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18. Crha, Igor et al. “Seminal Plasma Homocysteine, Folate and Cobalamin in Men with Obstructive and Non-Obstructive Azoospermia”. J Assist Reprod Genet 27.9-10 (2010): 533-538. Web.
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20. Jockenhövel, F. et al. “Seminal Lead and Copper in Fertile and Infertile Men: Blei und Kupfer im Spermaplasma Bei Fertilen und Infertilen Männern”. Andrologia 22.6 (1990): 503-511. Web.
21. Marzec-Wróblewska, Urszula et al. “Zinc and Iron Concentration and SOD Activity in Human Semen and Seminal Plasma”. Biol Trace Elem Res 143.1 (2010): 167-177. Web.
22. Slivkova, Jana et al. “Concentration of Trace Elements in Human Semen and Relation to Spermatozoa Quality”. Journal of Environmental Science and Health, Part A 44.4 (2009): 370-375. Web.