People could one day extend their lifespan by up to 30 years by taking a pill, a scientist has claimed. Professor John Speakman, from Aberdeen University said the hormone thyroxine could boost metabolism and so lifespan. He said tests on mice suggested, if the right dose could be identified, humans who would otherwise have died aged 70 could live to 100. But a leading hormone specialist warned too much thyroxine can cause potentially fatal health problems. Studies carried out by the Aberdeen University team showed the mice with the highest metabolic rate lived around 25% longer than those with the lowest. Professor Speakman said this would translate to a difference of around 30 years in humans. When mice were given thyroxine, they had increased metabolic rates and lived longer, compared with animals who were not given the hormone. Thyroxine is already given to people who do not produce enough of the hormone naturally, so that they have a healthy metabolic rate. But people with too much thyroxine in their bodies also have to take medication to bring their level back to normal.
