Many STIs cause no noticeable symptoms at all, which is one reason they spread so easily. When symptoms do appear, the most common sensations are burning during urination, itching in the genital area, unusual discharge, and sores or bumps on or around the genitals. What you actually feel depends entirely on which infection you have, and some feel like nothing for months or even years.
Most STIs Are Silent
The World Health Organization estimates that the majority of curable STIs are asymptomatic. That means the person carrying the infection has no burning, no itching, no visible signs. Chlamydia is a prime example: many people carry it for weeks or months without any clue. The same is true of gonorrhea, HPV, and early-stage HIV. So “what does having an STI feel like?” often has a frustrating answer: it feels like nothing. This is exactly why routine testing matters more than waiting for something to feel wrong.
Burning and Pain During Urination
The single most recognizable STI sensation is a burning feeling when you pee. Chlamydia, gonorrhea, and trichomoniasis all cause this. It typically feels like a sharp sting or heat concentrated at the opening of the urethra. With gonorrhea, the burning tends to appear quickly, often within 2 to 8 days of exposure. Chlamydia takes a bit longer, usually 1 to 3 weeks, and the burning can be milder or come and go.
Herpes can also make urination painful, but for a different reason. Open sores near the urethra sting when urine passes over them. This is a surface-level pain rather than the internal burning that chlamydia or gonorrhea produces.
Itching and Irritation
Persistent genital itching is another hallmark. Trichomoniasis causes vaginal itching, burning, and soreness, or an irritating feeling inside the penis. Genital herpes often begins with itching around the genitals, buttocks, or inner thighs before sores develop. HPV-related genital warts can cause mild itching or general discomfort in the area, though many people with warts feel nothing at all. Even hepatitis can cause widespread itching, though this tends to show up later as the liver is affected.
The itching from an STI differs from a yeast infection or jock itch in that it usually comes alongside other symptoms like discharge, sores, or pain. But in isolation, it’s impossible to tell the difference by feel alone.
Unusual Discharge and Odor
Several STIs alter what comes out of the body. Chlamydia and gonorrhea can both cause abnormal discharge from the penis or vagina. In men, gonorrhea often produces a thick, yellowish or greenish discharge from the penis. In women, the changes can be subtler and easier to dismiss.
Trichomoniasis has one of the more distinctive discharges: it can be clear, white, yellowish, or greenish, sometimes with a thin or frothy texture and a noticeable fishy smell. If your discharge has changed in color, consistency, or odor and you’ve had recent unprotected sex, that combination is worth taking seriously.
Sores, Bumps, and Skin Changes
Syphilis produces a sore called a chancre at the site of infection, usually on or around the genitals, anus, or mouth. Here’s what makes syphilis tricky: the sore is typically firm, round, and painless. Because it doesn’t hurt, people often miss it entirely. It appears an average of 21 days after exposure, though the window ranges from 10 to 90 days, and it heals on its own even without treatment. The infection, however, does not.
Herpes sores feel very different. The first outbreak usually starts with tingling or itching in a specific spot, followed by small blisters that break open into shallow, painful ulcers. The first episode tends to be the worst and can come with swollen lymph nodes and general achiness. Recurrent outbreaks are typically milder. Many people learn to recognize a “prodrome,” a tingling or burning sensation in the skin a day or two before sores reappear.
Genital warts from HPV are raised, flesh-colored growths that can be flat, rounded, or have a bumpy cauliflower-like texture. They’re usually painless, though large warts in certain locations can become uncomfortable or itchy. Warts may take anywhere from 3 weeks to many months to appear after exposure.
Flu-Like Symptoms and Whole-Body Effects
Some STIs cause symptoms that don’t feel “sexual” at all. Acute HIV infection, which occurs 1 to 2 weeks after exposure, often mimics a bad flu. Fever occurs in more than 70% of symptomatic cases. Fatigue is equally common. Muscle aches, sore throat, night sweats, swollen lymph nodes, and sometimes a rash round out the picture. About 20% of people develop oral or genital ulcers. These symptoms fade on their own within a few weeks, and then HIV can remain silent for months to years.
Secondary syphilis, the stage that follows if a chancre goes untreated, can also cause a rash, fever, sore throat, and swollen glands. Hepatitis B and C may cause fatigue, nausea, and joint pain weeks to months after infection, though many people with hepatitis feel fine for years.
Deep Pelvic Pain
When bacterial infections like chlamydia or gonorrhea go untreated, they can spread deeper into the reproductive tract. In women, this leads to pelvic inflammatory disease, which causes pain in the lower abdomen. This pain can range from a dull, persistent ache to sharper discomfort, and it sometimes shows up during sex. Left untreated, PID can cause long-term pelvic pain and damage to the fallopian tubes. In men, untreated infections can inflame the tube behind the testicle, causing swelling and pain on one side of the scrotum.
When Symptoms Appear
The gap between exposure and the first sign of trouble varies widely. Gonorrhea is one of the fastest, often producing symptoms within days. Chlamydia takes 1 to 3 weeks. Herpes blisters average about 4 days but can take up to 12. Trichomoniasis may take 5 to 28 days. Syphilis averages 3 weeks but can hide for up to 3 months. HPV-related warts can take months. HIV antibodies may not be detectable for weeks, and the virus can remain clinically silent for years.
These timelines matter because feeling fine a few days after unprotected sex doesn’t mean you’re in the clear. Many infections need weeks to incubate, and as noted above, many never produce symptoms at all. If you’re searching this question because you’re worried about a recent exposure, the timing of your symptoms (or lack of them) can help narrow the possibilities, but testing is the only way to know for sure.