Why Your Boyfriend Smells Like Fish Down Below & What to do About it

Why Your Boyfriend Smells Like Fish Down Below & What to do About it

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Article updated: April 26, 2023

Running a blog that is geared towards men’s health, hygiene, and grooming has elicited many strange questions from my readers over the years.

One such question that pops up in my inbox with surprising frequency is: Why does my boyfriend smell like fish down below?

Yes, believe it or not that question is asked far more frequently than you probably would’ve ever guessed or imagined.

Man on a skateboard

Now if my inbox was flooded with questions from men asking why their girlfriend smells like fish down below, now that would be a bit more understandable. Because, well, you know… that’s a fairly common thing that women deal with. No judgements from me ladies. I get it…. bacteria, pH balances, yeast, yadda yadda…. there’s a lot going on down there that needs attention, and shit happens.

Now men on the other hand aren’t commonly known to smell like a fish processing plant down below, but it does in fact happen.

While many men will never experience the unpleasantness of a fishy smelling package (thankfully), there are plenty of guys out there who suffer from this nasty issue.

So what the hell causes the male groin area to smell like fish? Is it normal? What can be done about it?

In this article I will cover all of these questions, offer some solutions, and hopefully, for your sake and sanity, put an end to the fishy smelling disaster that is known as your boyfriends package.

Causes of Fishy Smelling Groin in Men

Smegma – AKA “Dick Cheese”

As appetizing as cheese might be, I can assure you that you want no part of this sort of cheese. Smegma is probably the most disgusting natural body substance that will ever grace the planet earth. Aptly nicknamed “dick cheese”, smegma is a horrific smelling buildup that can occur around the head of an uncircumcised penis if proper hygiene is not being practiced. Consisting of sebum, dead skin cells, and sweat, smegma looks and often times smells like gooey white cheese, sour milk, and in some cases, fish.

Neon sign that says "Say Cheese"

Although smegma is typically associated with an uncircumcised penis, in can in fact develop on a circumcised penis if there are folds and creases present around the head. In fact smegma can even be found in the folds of the vagina, although this is typically less common.

So, smegma… gross right? The good news is that smegma is easily eradicated by good hygiene. The bad news is that your boyfriend’s hygiene probably sucks — hence the dick cheese. Smegma is easily prevented by thoroughly washing under the foreskin and in between folds, creases, and crevices located around the head of the penis.

If smegma is in fact present on your boyfriend’s penis, the first course of action should be to help improve his grooming and hygiene habits. For this I recommend using a soap that is specifically designed for a man’s groin area such as Chassis 5-in-1 Shower Primer. This unique body wash is formulated to provide a deep down clean while also helping to keep sweat and odor at bay throughout the day.

Dried Semen (Jizz)

One of the most common causes of a fishy smelling groin in men is dried up old semen. While fresh semen typically doesn’t smell like fish, it’s actually quite common for old, dry semen to have some unpleasant fishy notes to it.

While it’s not my job to speculate as to why your boyfriend might have dried up semen on his penis, I will say that one of the most common reasons is masturbation.

A single yellow banana with white cream on the tip against a red background

Yes, as I am sure you are well aware, most (i.e. all) men masturbate. While masturbation itself is extremely common and generally accepted as normal behavior, it can become a problem if the masturbator (your boyfriend) isn’t properly cleaning up after the deed is done. Semen that is allowed to dry on the penis can often develop a fishy odor once it starts to mingle with groin sweat and bacteria. The odor can become noticeably worse the longer your boyfriend goes without showering.

So even though old semen might be the cause of your boyfriend’s fishy smelling groin, the root of the problem is actually bad hygiene. While it can be tricky to get a grown man to change his bad hygiene ways, it’s certainly worth a conversation if his fishy smelling crotch is an issue for you (it should be).

If your serious about improving your boyfriend’s crotch hygiene, you might want to check out one of my previous articles covering the best soaps and body washes for men’s groin.

Poor Hygiene

Although your boyfriend might not want to admit it, it’s entirely possible that the cause of his fishy smelling crotch might simply be the result of piss poor hygiene.

One of the smelliest places on a man’s body (likely the smelliest) is the crotch/groin/ass hole region. The reason this area is capable of being so foul smelling is because it’s the perfect breeding ground for odor causing bacteria to thrive and multiply.

Since your boyfriend’s crotch spends the majority of its day constricted by underwear and pants, it’s highly likely that sweat and moisture is present throughout the day.

And if there is one thing that odor causing bacteria absolutely love, it’s a warm, moist environment. Once these bacteria get the party started, they begin forming products called thioalcohols. These thioalcohols have a very pungent odor which is often compared to sulfur, meat, onions, cheese, and in some cases fish.

The solution to preventing odor causing bacteria all comes down to hygiene and a little bit of preventative maintenance. If your boyfriend is lacking in the hygiene department, the problem is easily solved by him showering and thoroughly cleansing his junk on a daily basis. If you suspect that your boyfriend’s current showering routine is lacking, I recommend checking out my list of best soaps and washes for mens balls.

Urinary Tract Infection (UTI)

While it’s much more common for women to get UTI’s, men can certainly get them too. UTI’s occur when the urinary tract becomes infected by bacteria. Some of the most common causes of infection are from: Sex, urinary retention (an inability to drain all the urine from the bladder), diabetes, kidney stones, and an enlarged prostate.

While UTI’s present a wide range of symptoms, some of the most obvious symptoms include:

  • Fishy smelling penis
  • A frequent need to pee
  • Burning sensation while peeing
  • Dark urine
  • Foul smelling urine

The good news about UTI’s is that they are easily treated with antibiotics. If you or your boyfriend suspect that a UTI is the cause of their fishy smelling penis; a trip to the doctor’s office might be in order.

Yeast Infection (Penile Yeast Infection)

Kind of like a urinary tract infection, most people associate yeast infections with women. But what you might not know is that men can get yeast infections too.

Penile yeast infections are caused by an overgrowth of a certain type of fungus called candida. While candida is commonly found on the skin in small quantities, an overgrowth of this fungus can lead to a penile yeast infection.

Two of the most common causes of a candida overgrowth in men are:

  1. Having unprotected intercourse with a woman who has a yeast infection.
  2. Poor hygiene.

While the symptoms of a penile yeast infection can vary, some of the most common symptoms include:

  • Itching at the head of the penis
  • Burning or stinging at the head of the penis
  • Burning or stinging sensation while urinating
  • Moist skin on the penis
  • Areas of shiny, white skin on the penis
  • Redness and inflammation
  • Foul smelling discharge

The good news is that penile yeast infections are pretty easy to treat with over the counter topical anti-fungal ointments and creams. In serious cases a prescription strength treatment might be required.

Trimethylaminuria (Fish Odor Syndrome)

Since trimethylaminuria is a long ass word and pretty much impossible to pronounce, I’ll refer to this disorder simply as fish odor syndrome.

While it’s highly unlikely that fish odor syndrome is why your boyfriend smells like fish down below, I wanted to include it on this list because as unlikely as it may be, it’s still possible.

Fish odor syndrome is a rare metabolic disorder that causes sweat, urine, semen, and breath to give off a strong fishy odor.

Fish piled inside a yellow bin

While I’m not going to get too heavy into the science behind the disorder, I will say that the primary cause of fish odor syndrome is a defect in the way an enzyme called flavin-containing monooxygenase 3 is produced in the body.

Like I said, fish odor syndrome is extremely rare. It’s also more commonly found in women than men. That being said, if you suspect fish odor syndrome is the cause of your boyfriend’s fishy smelling groin, a simple urine or blood test is all that’s needed to diagnose.

If you want to learn more about fish odor syndrome you can do so here.

Thanks for reading. If you have any comments, questions, or experiences please share them in the comment section below.