Everything You Need to Know About Trichomoniasis

It's super common STI but — good news — easily curable.

Trichomoniasis
Photo: Alex Sandoval

"Peter Piper picked a peck of pickled peppers" might be the most common tongue-twister, but there's another tongue-twister you should know about if you're invested in your sexual health: Trichomoniasis.

Trichomoniasis is a sexually transmitted infection that is not commonly discussed but is super common amongst sex-havers — particularly those with vaginas. In fact, trichomoniasis is the most common curable STI — period. Data shows that nearly 2 million people in the U.S. test positive for trichomoniasis each year, the majority of whom are people with vaginas, according to the Centers for Disease Control and Prevention. (

Right about now, you're probably thinking, "Why haven't I heard of this hard-to-pronounce, yet very-common infection?" By the end of this story, you'll be up to speed on trichomoniasis.

Read on for everything sexually active people should know about trichomoniasis, its symptoms, treatment, transmission, and more.

What Is Trichomoniasis?

What's unique about trichomoniasis is that while other common STIs are either viral (herpes, HPV, HIV) or bacterial (gonorrhea, chlamydia, syphilis), trichomoniasis is not. "Trichomoniasis is a parasitic sexually transmitted infection that's caused by a parasite called the trichomonas vaginalis, which is a type of single-celled organism known as protozoan," explains Felice Gersh, M.D., author of PCOS SOS: A Gynecologist's Lifeline to Naturally Restore Your Rhythms, Hormones, and Happiness. In fact, if you were to look at this infection under the microscope, you'd be able to see it move around. "Under a microscope, it looks like a little tadpole — you can see the parasite's little tail (its flagella) moving around," she explains.

Feeling a little skeeved out that you could potentially have a parasite wiggling around your genitals? That's natural, but know that while your doctor may be able to see the parasite swimming under a microscope, you wouldn't notice them with the naked eye, explains Emily Rymland, D.N.P., F.N.P.-C., AAHIVS-certified HIV expert and clinical development manager at Nurx, a virtual healthcare platform. (Trichomoniasis is not like pubic lice or crabs in that way.)

How Do You Get Trichomoniasis, Exactly?

"The trichomoniasis can be transmitted through bodily fluids during sexual contact," says Rymland. Specifically, through P-in-V intercourse and scissoring (vagina-on-vagina contact), according to Dr. Gersh. "It's rare for trichomoniasis to be spread through oral and anal sex." That's because, due to its pH, the vagina is a more optimal environment for the trichomonas vaginalis parasite to live than the mouth or the anus, she says. The vagina is also a more ideal temperature and moistness for parasites, in general, compared to other body parts.

This is why trichomoniasis is more common in vagina-owners than people with penises. However, people with penises can still contract and spread trichomoniasis, and as such, people with all sorts of anatomies should know their current trichomoniasis status.

Trichomoniasis Symptoms

Trichomoniasis symptoms aren't as obvious as the symptoms of, say, chickenpox. The most common trichomoniasis symptom is actually no symptom at all, according to Dr. Gersh.

"Symptoms are present in less than 20 percent of people with the infection," she says. And the percentage of penis-owners who experience symptoms may be even lower. "It's unknown why some people develop symptoms and others do not," adds Rymland. People who do experience symptoms of trichomoniasis usually develop them within a month of infection, according to the U.K. National Health Service.

So what symptoms of trichomoniasis might show up? The most common symptoms for people with vaginas, according to Dr. Gersh, are:

  • heavy discharge with a distinctive, foul odor
  • discharge that is green and frothy or white or grey in color and chunky
  • burning with urination
  • irritation during intercourse
  • generalized genital itchiness

In people with penises, trichomoniasis can lead to:

  • urethritis (inflammation of the urethra)
  • painful urination
  • painful ejactulation
  • discharge from the penis
  • general irritation inside the penis

These trichomoniasis symptoms mirror those of other common genital infections such as yeast infections and/or bacterial vaginosis. As such, it's common for people to try to treat the symptoms with over-the-counter yeast infection meds, says Dr. Gersh. Obviously, this is unsuccessful. It's always a smart move to get in touch with your gynecologist or hed to your local Planned Parenthood if you notice something off with your genitals rather than trying to self-diagnose and self-treat, she says. (See: 6 Home Remedies for Yeast Infections That You Should Never Try)

Trichomoniasis Testing and Treatment

"Testing and treatment for trichomoniasis are both easy," says Rymland. "People with vaginas can be tested with a simple vaginal swab and people with penises can be tested through a urine test," she explains. And, unlike other STIs, you can be tested for trichomoniasis even if you don't have symptoms, meaning you can (and should) make it part of your regular STI testing routine. (See: How Often Should You Really Get Tested for STIs?)

Most health clinics offer STI testing, including university health centers, mobile testing centers, and urgent care facilities. If, however, you'd prefer to get tested in the comfort of your own home, you can opt for an at-home trichomoniasis testing kit from Nurx or Everlywell. (

If the trichomoniasis test is positive, you'll be prescribed a simple anti-parasite oral medication that will clear up the infectionin about a week. There are two medications that are commonly used, according to Dr. Gersh: Metronidazole, which is typically prescribed as a one-time large dose, and tinidazole which is typically prescribed with a lower dose taken twice a day for seven days. Whichever medication your doctor prescribes, you're going to want to avoid alcohol for a few days during treatment because "when mixed with alcohol, these medications can cause nausea," she says.

Above all, if you test positive for trichomoniasis, it's important that you avoid sex until the infection is totally cleared and inform all your recent sexual partners so that they can get tested and receive treatment, too. Trichomoniasis has an extraordinarily high re-infection rate (about 1 in 5), according to Dr. Gersh. "You don't get immunity to trichomoniasis just because you've had it once," she says. "So, it's common for someone to get re-infected within three months by someone who also has trichomoniasis, but who did not receive proper testing or treatment." Until everyone you're having sex with receives a negative trichomoniasis test, the risk of entering a reinfection cycle is high, she says. (See More: Your Guide to Dealing with a Positive STI Diagnosis)

Why Knowing Your Trichomoniasis Status Is So Important

Generally speaking, you should know your current status for all STIs! This information is vital in prioritizing your own health and protecting any/all of your sexual partners. It's also information your sexual partners need to have in order to give complete and total consent to a sexual encounter.

Beyond that, left untreated, trichomoniasis can have implications for your health. Due to the genital inflammation it creates, "people with trichomoniasis are more susceptible to other sexually transmitted infections, such as HIV," says Dr. Gersh. Reminder: HIV is a life-long infection. (

A trichomoniasis infection can also cause complications during pregnancy. "One study found that trichomoniasis was linked to a 30 percent increase in low-birth-weight infants and a 30 percent increase in preterm birth," says Dr. Gersh. "It's unknown why this is the case, but it supports the idea that you should know your trichomoniasis status."

ICYWW: Trichomoniasis can't travel up your reproductive tract, causing permanent scarring and pelvic inflammatory disease the way chlamydia and gonorrhea can. "But while trichomoniasis doesn't pose as much risk as other STIs, you should still know your trichomoniasis status so you can get treatment if you're positive," says Rymland.

How to Protect Yourself from Trichomoniasis

If you're sexually active, the only way to protect yourself from trichomoniasis is to know your own trichomoniasis status (by getting tested!) and know the STI status of your partner(s).

If you have a partner who has trichomoniasis and/or you don't know their STI status, it's important to understand that there is no way to guarantee that the parasite won't be transmitted, says Dr. Gersh. Wearing an external or internal condom during penetrative intercourse and a dental dam during scissoring (and other vagina-on-vagina sex acts), however, is your best protection method, she explains.

Just keep in mind that the infection can be transmitted from contact with the genital regions that are not covered by the barriers, she says. Meaning, using condoms can reduce — but not totally eliminate — your risk of getting trichomoniasis. So, if you find out a sexual partner has the infection, get tested. Given how easy testing is, there's really no excuse not to.

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