Beyond the risk of pregnancy, casual sex without a condom can open you up to a whole new (and not very pleasant) world of sexually transmitted diseases.
Despite this, only 15% of Brits bought condoms last year, with the UK ranking 33rd out of 36 countries in a Durex study. Yikes.
It tracks as Pharmacy2U has revealed sales of gonorrhoea and chlamydia tests has rocketed by a whopping 1,606.9% during the first two weeks of October.
While London has seen the greatest increase in demand, it’s followed by Birmingham, Edinburgh, Manchester and Leeds, with the spike coinciding with students’ return to university where they engage in Freshers.
So, be vigilant, as some infections take a while to show up and half of UK adults don’t recognise telltale signs they may be infected.
And, find out how long you need to wait to get tested for the most common STIs below – and get familiar with the symptoms too.
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Chlamydia
There were 168,889 chlamydia diagnoses across the country in 2024, so it’s imperative that you get checkout for it.
Dr Hana Patel, GP and consultant for Superdrug Online Doctor, tells Metro you should be tested for chlamydia about two weeks after unprotected sex, as ‘the bacteria needs time to multiply to detectible levels.’
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Symptoms mostly include burning when you wee and abdominal pain, according to the doctor. Specifically women may get bleeding between periods, while men may notice pain or swelling in the testicles.
However, Dr Patel notes: ‘Many people have no symptoms at all, which is why testing after unprotected sex is important.’
If you’re worried you could have it but don’t have symptoms you can order a self-test kit (which you can get for free if you’re under 25), but if you do have symptoms, book an appointment at the sexual health clinic or GP.
To test, you’ll need to give a wee sample or a swab to take fluid from your penis or vagina and possibly your bottom. If you get a positive result, it can be treated with oral antibiotics.
Lymphogranuloma venereum (LGV)
This is a more invasive strain of chlamydia that develops gradually.
‘Symptoms can appear anywhere between three and 30 days after exposure, but waiting until two weeks after sex to test improves the chances of detection,’ Dr Patel says.
The doctor explains this STI develops in stages, starting with small genital or rectal ulcers that can then lead to rectal pain, bleeding and swollen lymph nodes.
If you test positive for chlamydia with these symptoms, the lab will then test another swab sample from the affected area, or do a urine sample, which can take three weeks. Treatment usually involves a 21-day course of antibiotics.
Gonorrhoea
Again, Dr Patel suggests waiting two weeks to get tested after potential exposure to gonorrhoea, of which 71,802 cases were diagnosed in 2024.
‘Common symptoms include unusual discharge, burning during urination and pelvic or testicular pain,’ she says.
‘Women may experience more subtle symptoms than men, which can make the infection easy to overlook.’
If your swab or urine test proves positive, it’s typically treated with a single injection of ceftriaxone, sometimes combined with oral medication
Genital herpes (HSV-1 and HSV-2)
This one is a little different, with Dr Patel sayying, genital herpes (HSV-1 and HSV-2) ‘should be tested for with a swab as soon as symptoms appear.’
Typical symptoms include small blisters that break open into painful sores on the genitals or surrounding areas.
‘If you have had unprotected sex but do not have any symptoms, you should wait around 12 to 16 weeks before having a blood test,’ she adds.
‘This is because blood tests detect antibodies produced by your immune system, and these do not appear immediately after infection. Treatment for genital herpes usually involves antiviral medication such as aciclovir.’
Human papillomavirus (HPV)
This is the most common STI according to the GP. In fact, 80% of adults will contract it in their lifetime.
Women in the UK are screened for HPV through cervical screening from the age of 25, but there’s no routine test for men.
‘Some strains of HPV can cause small fleshy growths or bumps around the genitals or anus which can be removed with cryotherapy (freezing), topical creams or minor surgical procedures,’ Dr Patel explains.
Hepatitis A
‘Hepatitis A can be tested for between two and seven weeks after exposure because the virus can take several weeks to reach detectable levels in the blood,’ says Dr Patel.
‘Symptoms may include fever, nausea, abdominal pain and jaundice.’
This can’t be tested for at home – you’ll need to head to the doctors for a blood test. However, the good news is, most people recover fully with supportive care such as rest, fluids and monitoring.
Hepatitis B
According to Dr Patel, this is usually tested for ‘around six weeks to three months after unprotected sex.’
Similarly to Hepatitis A, it’s detected through a blood test, with the symptoms include abdominal pain and jaundice, as well as fatigue, although many people also have no noticeable symptoms.
‘Acute hepatitis B often resolves naturally, but chronic infection may require antiviral treatment to prevent long-term liver damage,’ she adds.
Syphilis
This less prevalent STI saw 9,535 diagnosed cases in the UK in 2024.
Dr Patel says you can test for it between four and 12 weeks after exposure because the antibodies need time to reach detectable levels, adding: ‘Syphilis symptoms can include a painless sore at the site of infection, swollen glands and, later, a rash on the palms of the hands or soles of the feet.’
As for the test itself, you’ll need either a blood test or a swab of the sore or lesion, and if you’re positive an injection of penicillin should treat it.
Shigella
Otherwise known as bacillary dysentery, this lesser-known STI has seen a spike in the UK in recent years.
‘Shigella should be tested for as soon as symptoms appear, typically through a stool sample,’ Dr Patel says.
These symptoms include diarrhoea, which could be bloody, along with stomach cramps and fever.
The doctor adds: ‘Treatment focuses on maintaining hydration, although antibiotics may be used in more severe cases.’
Trichomoniasis
This is a parasite that causes an STI known as trichomoniasis, which Dr Patel says can be tested for as early as one week after unprotected sex.
‘The parasite becomes detectable fairly quickly,’ she explains. ‘Symptoms may include vaginal discharge, genital itching and discomfort when passing urine, although many men have no symptoms at all.’
If a swab of the infected area or urine sample determines you have this STI, treatment is a course of oral antibiotics.
HIV
Recent estimates from the Terrence Higgins Trust suggest that more than 111,800 people in the UK are living with HIV. Of these, over 5,200 are undiagnosed and unaware they’ve contracted the infection.
So, it’s important to get tested if you think you’ve been exposed, but the waiting times may vary depending on the type of test used.
‘A laboratory blood test can generally detect infection from around four weeks after exposure, while finger-prick or rapid tests are more accurate from around six to twelve weeks,’ Dr Patel says.
‘These tests detect antibodies and, in some cases, viral antigens, which take time to appear after infection.’
Early symptoms may resemble a flu-like illness two to six weeks after infection, followed by a long period with no symptoms.
Unfortunately, there is no known cure, but current treatment involves lifelong antiretroviral therapy, which keeps the virus suppressed enough to be undetectable and allows people to remain healthy.
This article was first published on November 27, 2025, and has been updated.
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