Men who buy illegally-traded erectile dysfunction (ED) pills online have been warned they are gambling with their health - after authorities confiscated more than four million doses last year.
The Medicines and Healthcare products Regulatory Agency (MHRA) said criminals were exploiting "stigma and embarrassment" and many pills had no active ingredient, the wrong dose, or toxic ingredients.
The UK watchdog warned unlicensed pills were especially dangerous for men with heart disease, high blood pressure or those taking other medicines.
Working alongside Border Force agents, the MHRA confiscated 4.4 million doses last year and about 19.5 million between 2021 and 2025 - enough to fill two double-decker buses.
Andy Morling, head of the MHRA's criminal enforcement unit, said the pills might look like genuine brands but are "potentially dangerous".
"These products may contain no active ingredient, the wrong dose, hidden drugs or toxic ingredients," said Mr Morling.
He added: "These seizures show the sheer scale of the illegal market for erectile dysfunction medicines in the UK - and the risks people are taking without realising."
Seizures of illegal erectile dysfunction drugs have more than doubled since 2022, according to the MHRA, which is working with internet firms to block websites and social media accounts selling the rogue drugs.
It said more than 1,500 websites and 1,200 social media posts illegally selling medical products had been removed last year.
Mr Morling said: "These seizures show the sheer scale of the illegal market for erectile dysfunction medicines in the UK - and the risks people are taking without realising."
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Viagra (the brand name for sildenafil) became available without a prescription in the UK in 2018, with generic versions and other ED drugs now available over-the-counter and via online pharmacies.
The MHRA said buyers should only use UK-registered sites displaying an official green cross logo and that a list of registered online pharmacies can be found on the General Pharmaceutical Council's website.
(c) Sky News 2026: Men buying illegal erectile dysfunction pills are risking their health, says watchdog
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