Including why some men are growers vs. showers, and the nutritional value of semen.

Anthea Levi
February 20, 2018

As any loyal Health reader knows, we write about vaginas fairly often. So when The Penis Book ($17, amazon.com) arrived at our office, we figured it was only fair we give it a look. Let’s just say, we learned a lot. Author and urologist Aaron Spitz, MD, covers everything you've ever wondered about your man's member (from how erections happen, exactly, to average penis size), and some stuff you probably haven't thought about (like the protein content of semen—it's pretty high!). Below are five surprising facts we picked up in Dr. Spitz's guide.

Small penis syndrome is a "real medical condition"

We know that just like women, men have insecurities about their bodies too, of course. But we didn’t know that small penis syndrome is a serious form of anxiety. Dr. Spitz explains that men who struggle with the disorder aren’t just concerned their member isn’t as sizable as the next guy’s; they're are actually excessively worried about it. According to research published in the urology journal BJU International, the condition can manifest as a type of body dysmorphia, or “an obsessive rumination with compulsive checking rituals."

RELATED: Is It Really Possible to Break a Man’s Penis? A Urologist Explains

Semen is vitamin-rich

Yes, you read that right. According to Dr. Spitz, semen contains small amounts of vitamins B12 and C as well as minerals like zinc and magnesium. Also in spunk: protein and carbohydrates. About one quarter of a tablespoon of semen contains 160mg of protein and 10mg of carbs. The nutritional value shouldn't affect your decision to spit or swallow though, as Dr. Spitz points out: “Yes, it’s high in protein, but so is your snot, so that’s not necessarily a compelling argument to get your partner to open wide." We’ll stick with eggs as our go-to protein, thank you very much.

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Food can change the taste of semen

Internet legend has it that eating pineapple can change the way a woman’s vagina tastes. Dr. Spitz says certain foods can affect how semen tastes too. According to the urologist, a diet high in meat and dairy can make semen taste saltier, while fruits and veggies can make a man's secretions sweeter and "smoother." Since semen naturally contains fructose (the sugar found in fruit), it makes sense that eating foods with fructose might bring out its sweetness, writes Dr. Spitz.

Another diet tip for better-tasting semen: Drink plenty of H2O. “Semen is 90 percent water, and the more dilute the better when it comes to the palate,” writes Dr. Spitz. “Less hydration means more concentrated bodily fluids and more concentrated saltiness or bitterness.”

The average penis size is ...

Though there isn’t a ton of research on the length of a typical penis, one study from King’s College London concluded it's about 9 centimeters when soft (give or take 1.5 centimeters when stretched) and about 13 centimeters when erect. The researchers used their data to create a set of graphs to help doctors counsel men concerned about their penis size. "We believe these graphs will help doctors reassure the large majority of men that the size of their penis is in the normal range," author David Veale, MD, said in a press release.

RELATED: The Sex Position That’s Most Likely to Injure His Penis (Yes, Really)

Growers and showers have different tissue composition

The ‘growers versus showers’ phenomenon refers to the fact that some penises get considerably bigger when erect (the "growers"), while others tend to stay at a similar size whether they’re flaccid or hard (the "showers"). The reason for this “size surprise,” as Dr. Spitz puts it, has to do with the tissue makeup of a man’s member.

The sides of the penis are made up of a combination of collagen, which makes the penis durable, and elastin, which makes it stretchy. “Growers have more elastin and less collagen and showers have less elastin and more collagen,” explains Dr. Spitz.

The author adds: Growers are smaller at rest and larger at play, proving you "can’t judge a book by its cover."