Many STIs in men cause no symptoms at all, which means you can’t always tell by how you feel. When symptoms do show up, the most common signs are pain during urination, unusual discharge from the penis, sores or bumps in the genital area, or a rash. But the only reliable way to know your status is testing. Here’s what to look for and what to expect from the process.
Discharge and Pain During Urination
The two most common bacterial STIs, chlamydia and gonorrhea, share a signature set of symptoms in men: a burning sensation when you pee and discharge from the tip of the penis. Gonorrhea tends to produce a thicker, pus-like discharge, while chlamydia discharge is often thinner and more watery. Both can also cause mild testicular pain or swelling.
The catch is that many men with chlamydia, and a smaller portion with gonorrhea, never develop noticeable symptoms. You can carry and spread either infection for weeks or months without any sign something is wrong. If you’ve had unprotected sex and notice even mild burning or a slight dampness at the tip of your penis that wasn’t there before, those are worth taking seriously.
Trichomoniasis, a parasitic infection, produces similar symptoms: itching or irritation inside the penis, burning after urination or ejaculation, and sometimes a thin discharge. About 70% of people with trich have no symptoms at all, making it another infection you can easily miss without testing.
Sores, Bumps, and Blisters
Visible changes on or around your genitals point to a different set of infections. The key is knowing what you’re looking at, because the differences matter.
A syphilis sore (called a chancre) is typically a single, firm, painless round sore. It shows up at the spot where the infection entered your body, often on the penis, scrotum, or around the anus. Because it doesn’t hurt, many men don’t notice it or dismiss it as nothing. It heals on its own after a few weeks, but the infection continues progressing internally if untreated.
Genital herpes looks quite different. It produces clusters of small, painful, fluid-filled blisters that eventually break open into shallow sores. These tend to burn or sting and can make urination painful if they’re near the urethra. The first outbreak is usually the worst, often accompanied by flu-like symptoms such as body aches and swollen lymph nodes in the groin.
Genital warts from HPV appear as small bumps or groups of bumps in the genital area. They can be raised or flat, small or large, and sometimes have a rough, cauliflower-like texture. They’re painless and a healthcare provider can usually identify them on sight. Most strains of HPV that cause warts are low-risk for cancer, but other strains can cause problems without ever producing visible warts.
Symptoms That Don’t Look Like an STI
HIV and hepatitis often don’t produce genital symptoms at all, which is why many men never suspect them. Early HIV infection, roughly two to four weeks after exposure, can trigger what feels like a bad flu: fever, fatigue, sore throat, swollen lymph nodes, and sometimes a widespread rash. The rash can appear on the torso, face, or limbs. These symptoms fade on their own within a couple of weeks, and the infection then enters a long period with no obvious signs, sometimes lasting years.
Hepatitis B and C primarily affect the liver and may cause fatigue, nausea, dark urine, or yellowing of the skin and eyes, but many infections produce no symptoms for months or even years. By the time symptoms appear, significant liver damage may already be underway.
Why You Can’t Rely on Symptoms Alone
The core problem is that the most dangerous STIs are often the quietest. Chlamydia, HIV, hepatitis, HPV, and trichomoniasis can all be present with zero symptoms. Waiting for something to feel wrong is not a reliable strategy. If you’ve had unprotected sex, a new partner, or multiple partners, testing is the only way to actually know.
What Testing Looks Like
STI testing for men is simpler than most people expect. For chlamydia and gonorrhea, the standard test is a urine sample. You’ll be asked to hold your urine for at least an hour beforehand, then provide a “first-catch” sample (the initial stream, not midstream). Research shows urine-based testing is just as accurate as a urethral swab for detecting both infections in men, and clinical guidelines in multiple countries list it as the preferred method. No swab inside the penis is necessary for routine screening.
HIV, syphilis, and hepatitis are detected through blood tests. Some clinics offer rapid HIV tests using an oral cheek swab, with results in about 20 minutes. Herpes is typically diagnosed by swabbing an active sore, though blood tests can detect antibodies if no sore is present. Genital warts are diagnosed visually during a physical exam.
If you’ve had oral or anal sex, let the provider know. Throat and rectal swabs may be needed to check for gonorrhea and chlamydia at those sites, since a urine test only detects infections in the urethra.
When to Get Tested After Exposure
Testing too early after a potential exposure can produce a false negative, because your body hasn’t generated enough of the infection or immune response for the test to pick up. Each STI has a different detection window:
- Chlamydia and gonorrhea: Urine tests are generally reliable about two weeks after exposure.
- Syphilis: A blood test catches most infections at one month, and nearly all by three months.
- HIV (blood test): Detectable as early as two weeks with newer tests, with almost all infections caught by six weeks.
- HIV (oral swab): Catches most infections at one month, nearly all by three months.
- Hepatitis B: Blood tests are reliable at three to six weeks.
- Hepatitis C: Detectable for most people at two months, with nearly all infections caught by six months.
If your initial results come back negative but you tested early in the window, a follow-up test at the longer interval gives you a more definitive answer. This is especially important for HIV and hepatitis C, where the gap between “catches most” and “catches almost all” spans several weeks.
Where to Get Tested
You can get tested at your regular doctor’s office, a local health department, community health clinics, or sexual health clinics like those run by Planned Parenthood. Many of these offer free or low-cost testing, and some provide walk-in appointments with no need for a referral. At-home test kits for HIV and several other STIs are also available online and at pharmacies, though in-person testing allows for a broader panel and immediate guidance if something comes back positive.