Trichomoniasis in men is a sexually transmitted infection caused by a microscopic parasite that lives inside the urethra, the tube that runs through the penis. It is the most common nonviral STI in the world, with an estimated 82.6 million new infections in males globally in 2020 alone. Most men who have it don’t know it, because the infection often produces no symptoms at all.
How Men Get Trichomoniasis
The parasite responsible, called Trichomonas vaginalis, spreads during sex. It typically passes from a vagina to a penis or from a penis to a vagina. Once inside the male urethra, the parasite can survive for months or even years without treatment. Unlike bacteria, this is a single-celled organism with a tail-like structure that lets it move through the urethral lining and evade the immune system. The infection stays localized in the urogenital tract and does not spread to other parts of the body through the bloodstream.
Symptoms in Men
The majority of men with trichomoniasis are asymptomatic, meaning they feel perfectly fine and have no visible signs. This is the main reason the infection spreads so easily. Men can carry and transmit the parasite for a long time without ever suspecting they have it.
When symptoms do appear, they typically include:
- Urethral discharge: a thin or watery fluid from the tip of the penis, sometimes white or slightly cloudy
- Pain or burning during urination
- Irritation or itching inside the penis or at the tip
- Discomfort after ejaculation
These symptoms can be mild enough to dismiss or may come and go. They also overlap with other STIs like chlamydia and gonorrhea, which is why testing matters more than guessing based on symptoms alone.
How Trichomoniasis Is Diagnosed in Men
Diagnosing trichomoniasis in men used to be unreliable. Older methods like examining a sample under a microscope (wet mount) or growing the parasite in a lab culture had poor sensitivity, detecting only 44% to 75% of infections at best. Some rapid point-of-care tests perform even worse in men, with one common test catching only about 38% of male infections.
The most accurate option now is a molecular test that detects the parasite’s genetic material from a urine sample. One widely used version, cleared specifically for male urine specimens, has a sensitivity of 99.5% to 100% and a specificity above 99%. This means it catches virtually every true infection while almost never producing a false positive. If you’re being tested for trichomoniasis, a urine-based molecular test is the one you want. A simple urine sample is all that’s needed.
What Happens If It Goes Untreated
Because the infection can persist for years without symptoms, untreated trichomoniasis has time to cause real problems. In men, it has been linked to urethritis (inflammation of the urethra), epididymitis (painful swelling of the tube behind the testicle that stores sperm), and prostatitis (inflammation of the prostate gland). These conditions can cause chronic pelvic pain and may affect fertility.
There’s also a significant connection to HIV. Trichomoniasis causes low-level inflammation in the genital tract, which creates more entry points for the virus and increases the concentration of HIV in semen among men who are already living with HIV. Research from clinical settings in sub-Saharan Africa found that men with trichomoniasis had roughly 1.4 times the odds of also being HIV-positive compared to men without the infection. For men who are HIV-negative, having trichomoniasis raises the risk of acquiring HIV during future sexual encounters. For men who are HIV-positive, it increases the likelihood of passing the virus to a partner.
Treatment
Trichomoniasis is curable with a course of antiparasitic medication, typically taken by mouth. For men, treatment is usually a single dose, which makes it straightforward. The medication kills the parasite effectively in the vast majority of cases. You should avoid alcohol during treatment and for a period afterward, because the combination can cause nausea and vomiting.
Both you and your sexual partner need to be treated at the same time. If only one person takes the medication, the parasite simply passes back during the next sexual contact. This back-and-forth reinfection is one of the most common reasons people think the treatment “didn’t work.” You’ll need to abstain from sex until both you and your partner have completed treatment and any symptoms have fully resolved.
Why Partner Treatment Matters
Because so many men carry trichomoniasis without symptoms, the infection often gets diagnosed first in a female partner. If your partner has been diagnosed, you almost certainly need treatment too, even if you feel fine. Waiting for your own test results before starting treatment increases the window for reinfection. Many clinics offer expedited partner therapy, where your partner’s provider can prescribe medication for you without requiring a separate office visit. This approach reduces the gap between one partner’s treatment and the other’s, which lowers reinfection rates significantly.
After treatment, retesting is not always routine for men, but it may be recommended if symptoms persist or if reinfection is suspected. If a retest is done, it should happen at least two weeks after finishing the medication, because molecular tests are sensitive enough to pick up dead parasite fragments for a short window after successful treatment, which could produce a misleading positive result.