Brace yourself, because we’re about to get all high school health class over here. Call it what you like, but everyone’s wondered at one point or another what’s going on with semen—and maybe even what happens when we consume it. Is semen high in calories? Does a teaspoon of the gooey stuff provide our muscles with extra protein? Is it a nutritional sinkhole or a secret superfood? For better or worse, we’re getting to the sticky, icky bottom of this eternal mystery.

Love Potion No. 9—How Semen Gets Made

Male ejaculate isn’t just about those lil’ swimmers. (But remember kids: No glove, no love.) Semen is a viscous liquid composed of sperm (aka male reproductive cells) and various other secretions from the male reproductive system that are released during ejaculation. The potent brew is designed to pave the way out of the penis and make it easier help sperm reach their target and fertilize eggs. Mother nature thinks of everything, right?

Sperm cells are produced within the testicles in densely coiled tubes called seminiferous tubules (say that 10 times fast!). After this step (called "spermatogenesis"), sperm hang out in the epididymis (a series of ducts behind the testes), where they mature for about one day. When sexytime comes around, sperm conga-line through the vas deferens, the ejaculatory ducts, and finally out through the urethra. But that’s not all, folks! A lonely little sperm cell without any help or protection would never get to the endzone. Along the journey from testes to “the tip," other glands and ducts contribute the extra fluids that make up semen. The prostate produces a slightly alkaline liquid called prostatic fluid, which makes up most of the volume of semen. The seminal vesicles and Bulbourethral glands also produce fluids that go along for the ride. Each of these add-ins has an important function in baby-making: Prostatic fluid neutralizes the slightly acidic vaginal environment; seminal fluid contains fructose (aka sugar), fatty acids, and proteins to nourish the sperm; and Bulbourethral fluid cleans out any urine in the urethra and lubricates the dude’s ahem, hardware, too A neglected gland: a review of Cowper’s gland. Chughtai B, Sawas A, O’Malley RL, Naik RR, Ali Khan S, Pentyala S. Department of Urology, SUNY at Stony Brook, Stony Brook, NY, USA. International Journal of Andrology. 2005 April; 28(2):74-7.. Now that we know how semen is made, let’s take a closer look at the, er, nutritional side of things.

Special Sauce—The Answer/Debate

Nobody needs to know the how’s or why’s, but since we’re all adults here, we can acknowledge that sometimes semen ends up in unexpected places. Fortunately, a bit of love juice isn’t likely to ruin that low-fat, low-cal, no-sugar cleanse. A normal male ejaculation (about one teaspoon’s worth) contains between five and 25 calories and a minimal amount of protein. Semen is only one percent sperm; the rest is composed of over 200 separate proteins, as well as vitamins and minerals including vitamin C, calcium, chlorine, citric acid, fructose, lactic acid, magnesium, nitrogen, phosphorus, potassium, sodium, vitamin B12, and zinc Proteins of human semen. I. Two-dimensional mapping of human seminal fluid. Edwards JJ, Tollaksen SL, Anderson NG. Clinical Chemistry. 1981 August; 27(8):1335-40.. Levels of these compounds (including sperm count and mobility) vary depending on age, weight, and lifestyle habits like diet and exercise Dietary patterns and semen quality in young men. Gaskins AJ, Colaci DS, Mendiola J, Swan SH, Chavarro JE. Department of Nutrition, Harvard School of Public Health, Boston, MA, USA. Human Reproduction. 2012 October; 27(10):2899-907.. That said, we’re talking about one teaspoon of total fluid here—semen is hardly going to make it onto the food pyramid anytime soon. For anyone worried about getting enough protein, we heartily recommend sticking to more conventional sources. Even though it will likely never become a new diet craze, semen can have some positive effects on the body. A study showed that sexually active women who came in contact with semen in the reproductive tract were less depressed than their counterparts who used condoms Does semen have antidepressant properties? Gallup GG Jr, Burch RL, Platek SM. Department of Psychology, State University of New York at Albany, Albany, NY, USA. Archives of Sexual Behavior. 2002 June; 31(3):289-93.. Contact with semen has also been proven to reduce the risk of preeclampsia, a serious pregnancy complication Sperm exposure and development of preeclampsia. Einarsson JI, Sangi-Haghpeykar H, Gardner MO. Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA. American Journal of Obstetrics and Gynecology. 2003 May; 188(5):1241-3. Correlation between oral sex and a low incidence of preeclampsia: a role for soluble HLA in seminal fluid? Koelman CA, Coumans AB, Nijman HW, Doxiadis II, Dekker GA, Claas FH. Department of Immunohematology and Blood Bank, Leiden University Medical Centre, Leiden, The Netherlands. Journal of Reproductive Immunology. 2000 March; 46(2):155-66.. That said, forgoing a condom can have some serious repercussions (pregnancy and STIs come to mind), so take these studies with a grain (or the whole shaker) of salt.

The Takeaway

Sorry, ladies and gents, but we’re putting this ninth grade rumor to rest once and for all. Despite the complex compounds that make up each drop of ejaculate, semen doesn’t have significant concentrations of protein or calories.