Many STIs in men cause no symptoms at all, which means you can’t rely on how you feel to know whether you’re infected. When symptoms do appear, the most common signs include unusual discharge from the penis, burning during urination, sores or bumps on the genitals, and pain or swelling in the testicles. But each STI has its own pattern, and knowing what to look for can help you act faster.
Why You Might Have No Symptoms
This is the most important thing to understand: some of the most common STIs, especially chlamydia and gonorrhea, frequently cause no noticeable symptoms in men. You can carry and transmit these infections for weeks or months without feeling anything unusual. HIV, syphilis, and herpes can also have long stretches with no visible signs. If you’ve had unprotected sex or a new partner, the absence of symptoms does not mean you’re in the clear.
Discharge, Burning, or Pain
Chlamydia and gonorrhea are the two STIs most likely to cause discharge from the penis. With chlamydia, the discharge is often clear or slightly cloudy, and you may notice a burning sensation when you urinate. Symptoms, if they appear at all, typically show up several weeks after exposure. Testicle pain or swelling can also occur, though that’s less common.
Gonorrhea tends to produce more obvious symptoms than chlamydia. The discharge is often thicker and may be white, yellow, or greenish. Burning during urination is common. Gonorrhea can also infect the throat (from oral sex) or rectum (from anal sex), causing soreness, discharge, or bleeding in those areas. If it spreads further, it can cause joint swelling and pain.
Both infections are easily treated once diagnosed, but left alone they can lead to epididymitis, a painful inflammation of the tube behind the testicle. Untreated epididymitis can cause chronic pain and, in some cases, affect fertility.
Sores, Bumps, or Blisters
If you notice a sore on or around your genitals, two STIs are the most likely causes: syphilis and herpes. They look and feel quite different from each other.
A syphilis sore, called a chancre, is typically firm, round, and painless. It can appear on the head of the penis, the shaft, or around the anus or mouth. Because it doesn’t hurt, it’s easy to miss entirely. It usually shows up about three weeks after exposure, lasts a few weeks, and then heals on its own. But the infection doesn’t go away. It progresses to later stages that can cause rashes on the palms and soles, and eventually serious damage to organs if untreated.
Herpes sores are different. They usually start as small, painful blisters that break open into shallow ulcers. You may feel tingling or itching before the blisters appear. The first outbreak tends to be the worst, sometimes accompanied by flu-like symptoms, and can last two to four weeks. After that, the virus stays in your body and can cause recurring outbreaks, though these are usually milder.
Genital warts from HPV look nothing like either of these. They appear as small, skin-colored bumps, sometimes with a rough, cauliflower-like texture. They’re usually painless and can be so small and flat you might not notice them. Warts can show up weeks to months after exposure.
Flu-Like Symptoms After Exposure
About two to four weeks after contracting HIV, many people develop what feels like a bad flu: fever, fatigue, sore throat, swollen glands, body aches, and sometimes a rash. This is called acute HIV infection, and it happens as your immune system first responds to the virus. The rash can appear on the torso, face, or limbs.
These symptoms go away on their own within a couple of weeks, and then the virus enters a long phase where you may feel completely fine for years while it slowly damages your immune system. That initial flu-like illness is often the only early warning sign.
What Testing Looks Like
Getting tested is straightforward and usually involves one or more of three things: a urine sample, a blood draw, or a swab. Chlamydia and gonorrhea are most commonly tested with a urine sample. You urinate into a cup, and that’s it. If you’ve had oral or anal sex, your provider may also swab your throat or rectum.
Syphilis, HIV, hepatitis B, and hepatitis C are diagnosed with blood tests. A small sample is drawn from your arm. Herpes can also be tested through blood, or through a swab of an active sore if one is present. If you have visible warts or sores, a provider may examine or swab them directly.
There are no routine screening tests for HPV in men. If warts are present, a provider can diagnose them visually.
When Tests Become Accurate
Testing too soon after exposure can produce a false negative. Each STI has its own window period, the minimum time your body needs to produce a detectable infection or immune response.
- Chlamydia and gonorrhea: One week catches most infections. Two weeks catches nearly all.
- Syphilis: A blood test catches most cases at one month. Three months catches nearly all.
- HIV (blood test): Two weeks catches most with newer antigen/antibody tests. Six weeks catches nearly all.
- HIV (oral swab): One month catches most. Three months catches nearly all.
- Herpes (blood test): One month catches most. Four months catches nearly all.
- Hepatitis B: Three to six weeks.
- Hepatitis C: Two months catches most. Six months catches nearly all.
If your initial test is negative but you’re still within the window period, repeat testing later gives a more reliable result.
Who Should Get Tested Routinely
The CDC recommends that all men ages 13 to 64 get tested for HIV at least once, even without symptoms or known exposure. Beyond that baseline, screening recommendations depend on your situation.
Men who have sex with men should be tested at least annually for chlamydia, gonorrhea, syphilis, and HIV, regardless of condom use. If you have multiple partners, are on PrEP, or are living with HIV, testing every three to six months is recommended. Hepatitis B testing is also recommended for all men who have sex with men.
For men who have sex only with women, routine chlamydia and gonorrhea screening isn’t broadly recommended unless you’re in a higher-risk setting. Syphilis screening is recommended if you’re under 29, have a history of incarceration, or have other risk factors. Hepatitis C screening is recommended for all adults over 18 at least once.
Any time you have a new partner, notice symptoms, or learn that a past partner has been diagnosed with something, testing is the only reliable way to know your status. Most STIs are highly treatable when caught early, and several of the most common ones clear completely with a short course of treatment.