Originally published 2019-04-15.
A condom that changes colour when it detects a sexually transmitted infection is, so far, an idea rather than something you can buy. It was dreamed up in 2015 by three schoolboys at the Isaac Newton Academy in Ilford, east London, who called it S.T.EYE and won the healthcare category of the UK's TeenTech Awards with it. Their concept made headlines around the world, but no such condom has been approved or sold.
Here is what the students proposed, how it was meant to work, why scientists and reporters raised questions, and what actually protects you from STIs today.
Who came up with the idea
The inventors were Daanyaal Ali, Chirag Shah and Muaz Nawaz, aged 13 and 14 at the time. They entered TeenTech, a UK programme that encourages teenagers to design technology solutions for real problems, and their entry took the healthcare award. The prize included a cash award and a visit to Buckingham Palace, and the judging panel for the category included the television doctor Christian Jessen.
The boys admitted they were nervous about pitching something so personal. Muaz said they worried some people would think they were treating a serious subject as a joke. Their school described the entry as a little risqué but praised its originality and design.
The story was picked up by outlets including Time, CNN and the Washington Post, and Time reported that condom companies had already approached the team about the idea.
How the colour-changing condom was supposed to work
The concept borrows the logic of many rapid diagnostic tests. The condom would carry antibodies that latch on to antigens, the molecular markers of specific infections. If bodily fluids containing those antigens touched the latex, the binding reaction would trigger a visible colour change.
Press reports described a colour code for different infections:
- Green for chlamydia
- Yellow for herpes
- Purple for human papillomavirus (HPV)
- Blue for syphilis
The students' main argument was privacy. Many people put off testing because a clinic visit feels awkward. As Daanyaal Ali told CNN: "People find it embarrassing to go to the clinic so this makes sure that their privacy is maintained." He also stressed that anyone who saw a colour change would still need to visit a clinic for proper testing and treatment.
The open questions
An award for a clever idea is not the same as a working medical test, and the concept left several practical problems unsolved. Time's report noted that the idea was at a very early stage and listed some of them:
- Would a colour change mean the wearer had an infection, the partner, or both?
- What would happen if the condom met more than one infection at once?
- Could anyone realistically notice and interpret a colour change in the moment?
- How would people with colour blindness read the result?
There are scientific hurdles too. Diagnostic tests need to be validated for sensitivity (how often they catch a real infection) and specificity (how often they avoid false alarms). A false positive could cause panic and damage a relationship; a false negative could give dangerous reassurance. Some infections, such as herpes and HPV, can be passed on without any obvious fluids or symptoms, which would make them hard to flag this way. Any coating would also have to leave the condom's strength, shelf life and barrier protection untouched, and the finished product would need regulatory approval as a medical device.
None of that makes the idea foolish. It simply explains why, years later, there is still no colour-changing STI condom on shop shelves.
How well ordinary condoms protect you
Standard condoms remain one of the most effective tools for safer sex. According to figures summarised on Wikipedia's condom article, they are about 98% effective at preventing pregnancy with perfect use, falling to roughly 82% with typical, real-world use, mostly because of inconsistent or incorrect use.
For infections, latex condoms give strong protection against HIV, gonorrhoea, chlamydia, trichomoniasis and hepatitis B. They protect less fully against infections spread by skin-to-skin contact, such as genital herpes, HPV and syphilis, because they do not cover every area. Lambskin condoms block sperm but are much less effective against infections. If you have a latex allergy, polyurethane or polyisoprene condoms are alternatives.
Why the idea struck a nerve
The headlines spread because the idea speaks to a real worry: you cannot see an infection, and you often have to take a partner's word about their status. Deliberate lying happens, but far more often a person simply does not know they are infected. Many STIs, including chlamydia, frequently cause no symptoms at all, so people pass them on without realising.
That is why the most reliable answer today is unglamorous: regular testing for you and your partners, honest conversations, and consistent condom use. Free and confidential testing is available through sexual health clinics in many countries, and some services offer home testing kits. If you are worried about an infection, talk to a doctor or a sexual health clinic.
Myths and facts
Myth: You can buy condoms that detect STIs. No approved product does this. S.T.EYE was a student concept.
Myth: Condoms protect equally against all STIs. They are very effective against fluid-borne infections but less complete against those passed through skin contact.
Myth: Someone with an STI would know. Many infections are symptomless for long periods, which is exactly why testing matters.
The three Ilford teenagers did not solve STI testing, but they showed how young inventors can spot a real gap. For now, the safest approach combines condoms with regular check-ups rather than waiting for a condom that changes colour.
Sources: First shared by Healthy Holistic Living; TechXplore: UK youths design colour-changing condom for STIs; Time: STD-sensitive condoms; Wikipedia: Condom.
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