A doctor has discovered why cold weather causes men's penises to shrink dramatically in cold temperatures. It's a phenomenon as old as humans themselves, with most men having experienced extreme shrinkage of their penis at some point.

"This happens due to restricted blood flow, as the body prioritizes other, more important areas to maintain heat, such as the vital organs located in our core." The testicles contract to stay as close to the body as possible and retain heat, he explained Dr. Grant.

He says it's a "completely natural reaction" to the colder weather and shouldn't be a cause for concern.

"The reaction can last as long as the body is exposed to cold temperatures, and the size returns to normal after the body returns to a warmer and more comfortable state," he added.

Dr Grant advised anyone experiencing long-term changes in the shape and size of their genitalia to consult a GP for further advice, to rule out any worrying medical conditions.

He also shared advice for those already suffering from erectile dysfunction, as – although not directly related – the 'winter penis' can affect men's ability to 'achieve and maintain an erection'.

“As previously stated, cold weather restricts blood flow throughout the body, dramatically affecting the quality of an erection as the body prioritizes more important parts of the body. Therefore, men who already suffer from erectile dysfunction may find it more difficult to control their erections when the weather starts to deteriorate," he said.