Most STIs in men produce no symptoms at all, which means you can’t rely on how you feel to know whether you’re infected. Studies tracking men with confirmed chlamydia found that 94% reported no symptoms, and among men with gonorrhea, roughly 88% had none either. The only reliable way to know is to get tested. That said, when symptoms do appear, they tend to follow recognizable patterns worth understanding.
The Most Common Warning Signs
The symptoms that do show up in men tend to cluster around a few body areas: the penis, the testicles, and the rectum. Here’s what to watch for with the most common infections:
- Chlamydia: Burning during urination, discharge from the penis, and pain or swelling in one or both testicles. If transmitted through anal sex, you may notice rectal pain, discharge, or bleeding.
- Gonorrhea: Thick, cloudy, or bloody discharge from the penis, burning when you urinate, and swollen testicles. Rectal symptoms include soreness, itching, discharge, and painful bowel movements.
- Trichomoniasis: Discharge from the penis, itching or irritation inside the urethra, and painful urination. Symptoms are often mild and easy to overlook.
- Genital herpes: Small red bumps or blisters that break open into painful sores, typically around the genitals, rectum, or mouth. You may feel itching or tenderness around your inner thighs, buttocks, and genital area. Urination can sting if urine contacts an open sore.
- HPV (genital warts): A small bump or cluster of bumps in the genital area. They can be flat or raised, and larger clusters sometimes take on a cauliflower-like shape. Itching is common.
Burning during urination and unusual discharge are the two symptoms that send most men to a clinic. If you notice either one, that’s a strong signal to get tested, but the absence of these symptoms means very little on its own.
How Sores and Bumps Differ by Infection
If you notice a sore on or around your genitals, the characteristics of that sore point toward different infections. A syphilis sore, called a chancre, is typically a single, firm, round sore that doesn’t hurt. It appears at the spot where the bacteria entered your body and heals on its own within a few weeks, which leads many men to assume it was nothing serious. The infection, however, continues to progress.
Herpes sores look different. They usually appear as a cluster of small, painful blisters that rupture and leave shallow ulcers. Pain, tingling, and itching are hallmarks of herpes, while syphilis sores are notably painless. Both infections can present in unusual ways, though, so a visual guess is never a substitute for a lab test.
HPV warts are distinct from both. They’re flesh-colored bumps that don’t ulcerate or blister. They grow slowly and are typically painless, though they may itch.
HIV Feels Like the Flu at First
About two-thirds of people infected with HIV develop flu-like symptoms within two to four weeks of exposure. These include fever, chills, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes, a rash, and mouth ulcers. The combination of a rash with flu symptoms shortly after a potential exposure is particularly suggestive.
These symptoms typically resolve on their own within a week or two, and then the virus can remain silent for months or years. That initial flu-like phase is easy to dismiss, especially if you weren’t thinking about HIV risk at the time. By the time more serious immune problems develop, years of untreated infection may have passed.
Why You Can’t Wait for Symptoms
The asymptomatic rates for the most common bacterial STIs in men are strikingly high. A multi-country study published in the journal Sexually Transmitted Infections found that the proportion of men with chlamydia who reported no symptoms ranged from 94% to 100%, depending on the time period measured. For gonorrhea, the asymptomatic range was 67% to 100%. These aren’t rare exceptions. Symptom-free infection is the norm, not the outlier.
This matters for two reasons. First, untreated chlamydia and gonorrhea can spread to a partner without either of you knowing. Second, even in men, untreated infections can cause complications like inflammation of the tube behind the testicle, which leads to pain and, in some cases, fertility problems. Syphilis left untreated progresses through stages that can eventually damage the brain, heart, and other organs.
What STI Testing Actually Involves
If you’re picturing an uncomfortable swab inserted into the urethra, that’s mostly outdated. The CDC-recommended test for chlamydia and gonorrhea in men is a nucleic acid amplification test, and a simple urine sample is the standard specimen. You urinate into a cup, and the lab analyzes it. No swab required for most routine screening.
That said, urine samples aren’t equally sensitive for every infection. Research comparing urine to a gentle external swab of the penile opening found that urine detected 77% of chlamydia cases while the swab caught 94%. For trichomoniasis, urine missed more than half of infections, detecting only 39% compared to 80% with a swab. For gonorrhea, urine performed reasonably well at 89%. If your provider suspects trichomoniasis specifically, a swab may be more appropriate than urine alone.
For herpes, testing typically involves a swab of an active sore or a blood test that detects antibodies. Syphilis is diagnosed through a blood test. HIV is also a blood test, though rapid oral fluid tests exist and can give results in about 20 minutes.
When to Test After Exposure
Every STI has a window period, the gap between when you’re infected and when a test can reliably detect it. Testing too early produces false negatives.
- Chlamydia and gonorrhea: Wait at least one to three weeks after exposure for accurate results.
- Syphilis: The window ranges from 10 to 90 days, with an average of about three weeks.
- HIV: A fourth-generation test (which checks for both antibodies and a viral protein) is generally reliable by about three to four weeks, though some guidelines recommend confirming with a follow-up test at the 90-day mark for maximum certainty.
- Herpes: Blood antibody tests may not turn positive for several weeks to three months after infection. Swab tests of active sores, however, work during an outbreak regardless of timing.
If you test negative during the window period but had a genuine exposure, repeat testing after the full window has passed gives you a more definitive answer.
Who Should Get Tested and How Often
There’s no single screening schedule that applies to all men. The U.S. Preventive Services Task Force hasn’t established a universal chlamydia and gonorrhea screening recommendation for men the way it has for sexually active young women, largely because there isn’t enough research on whether routine screening in men reduces long-term complications. That doesn’t mean testing isn’t important. It means the decision is based on your individual risk.
Men who have sex with men are generally advised to test for syphilis, chlamydia, gonorrhea, and HIV at least annually, and every three to six months if they have multiple partners. Sexually active men with new partners, inconsistent condom use, or a partner who has tested positive for an STI all have good reason to test. HIV screening at least once is recommended for everyone between the ages of 15 and 65, regardless of perceived risk. If you’re unsure whether testing makes sense for you, a straightforward conversation with a provider or a visit to a sexual health clinic can sort it out quickly.