Several sexually transmitted infections can cause burning when you pee, but the most common culprits are chlamydia, gonorrhea, trichomoniasis, and genital herpes. The burning happens because these infections inflame the urethra, the narrow tube that carries urine out of your body. As urine passes over inflamed or damaged tissue, it triggers that stinging, burning sensation.
Why STIs Cause Burning
The urethra is lined with delicate cells. When bacteria, parasites, or viruses from an STI infect these cells, they trigger inflammation or outright kill the cells as they replicate inside them. This is called urethritis. The damaged, swollen lining becomes extremely sensitive, so even the normal flow of urine feels painful. Some infections also cause discharge from the urethra, and the irritation from that discharge adds to the discomfort.
Chlamydia
Chlamydia is one of the most common STIs linked to burning urination. It’s caused by bacteria that invade the cells lining the urethra and destroy them during replication. Symptoms typically show up 5 to 14 days after exposure, though many people never develop symptoms at all. When symptoms do appear, they’re often mild enough to be mistaken for a urinary tract infection.
Along with burning, you might notice a yellow or unusual discharge, more frequent urination, or (in women) bleeding between periods or during sex. Because chlamydia is so often silent, it can go untreated and lead to complications like infertility in both men and women.
Gonorrhea
Gonorrhea causes similar symptoms to chlamydia and the two infections frequently occur together. Burning with urination is a hallmark, along with discharge that can range from thin to thick and yellow. In men, symptoms tend to appear within about five days of exposure. In women, symptoms generally develop within 10 days, though gonorrhea also often causes no noticeable symptoms.
Like chlamydia, gonorrhea symptoms overlap heavily with a UTI. The key difference is that gonorrhea is more likely to produce noticeable discharge and can also cause rectal pain or bleeding if the infection spreads to that area.
Trichomoniasis
Trichomoniasis is caused by a parasite rather than bacteria, and it’s a frequently overlooked cause of painful urination. Symptoms can appear anywhere from 5 to 28 days after exposure, a wider window than most bacterial STIs.
In women, trich often produces a thin, frothy vaginal discharge that can be clear, white, yellow, or green and has a noticeable foul smell. Genital burning, soreness, itching, and pain during sex or urination are common. In men, trichomoniasis rarely causes obvious symptoms, but when it does, burning with urination and irritation inside the penis are the main complaints. Many people with trich have no symptoms at all.
Genital Herpes
Genital herpes, caused by herpes simplex virus, can produce intense burning during urination. The mechanism is slightly different from bacterial STIs. Herpes causes open sores or ulcers on or near the genitals, and urine passing over these raw areas creates sharp pain. The virus can also infect the urethra directly, adding internal inflammation on top of the external soreness.
Herpes symptoms tend to appear within about 12 days of exposure. A first outbreak typically includes pain, itching, tender swollen lymph nodes in the groin, and a clear discharge alongside the sores. The burning during urination can be severe enough that it’s sometimes the symptom that drives people to seek care. Notably, the level of pain with herpes is often out of proportion to what a standard urine test would show, which can help distinguish it from a UTI or bacterial STI.
Mycoplasma Genitalium
A lesser-known infection called Mycoplasma genitalium is an increasingly recognized cause of urethritis and burning urination. It’s a bacteria that doesn’t show up on standard STI panels in many clinics, which means it can persist undetected. It’s particularly common among people with non-gonococcal urethritis, a diagnosis given when there’s clear urethral inflammation but tests for chlamydia and gonorrhea come back negative. If you’ve been treated for a UTI or STI but the burning hasn’t gone away, this infection is worth asking about.
How to Tell an STI Apart From a UTI
Burning urination is a classic symptom of urinary tract infections too, which makes it tricky to self-diagnose. A few patterns can help you sort out what’s more likely.
UTIs tend to cause frequent urination, cloudy urine, and mild lower abdominal pain without any unusual discharge from the vagina or penis. STIs are more likely to produce abnormal discharge, genital sores or blisters, itchiness, pain during sex, and in women, heavier or more painful periods or bleeding between cycles. Blood in the urine is more common with UTIs but can occasionally appear with certain STIs as well.
The overlap is real, and both conditions can exist at the same time. If you’ve had a new sexual partner or unprotected sex in the weeks before symptoms started, STI testing is worth pursuing even if a UTI seems like the obvious explanation.
Getting Tested
The gold-standard test for chlamydia and gonorrhea is a nucleic acid amplification test, which detects genetic material from the bacteria. For men, this is typically done with a urine sample. For women, a vaginal swab (self-collected or taken during an exam) works as well. Trichomoniasis is diagnosed through a similar swab or urine test, and herpes is usually confirmed by swabbing an active sore.
If your initial tests come back negative but the burning continues, ask specifically about Mycoplasma genitalium testing, which requires a separate test that not all clinics run automatically. Most STIs that cause burning are curable with the right treatment, and herpes, while not curable, can be managed effectively to reduce symptoms and outbreaks.
Because chlamydia, gonorrhea, and trichomoniasis are so often asymptomatic, it’s common for people to carry and transmit these infections without knowing it. Burning urination is actually a useful signal, one your body is sending you that something needs attention.