Inventors have created a soap infused with caffeine which helps users wake up in the morning.

The soap, called Shower Shock, supplies the caffeine equivalent of two cups of coffee per wash, with the stimulant absorbed naturally through the skin, manufacturers say.

"Tired of waking up and having to wait for your morning (coffee) to brew?" ask the makers, thinkgeek.com.

Scented with peppermint oil, each bar is designed to provide a stimulant boost within five minutes.