Humans have been indelibly marking their skin with ink for thousands of years, but why did we start to tattoo ourselves and how does it work? As always science has the answers, and this week Luke has been delving into the research and experiments to bring us the most fascinating knowledge - including why getting a tattoo can have a positive impact on your mental health, and why our own immune systems is the reason behind how tattoos work. Listen and subscribe to Show Me the Science on Apple Podcasts ,Google Podcasts and Spotify. Download, listen and subscribe on the Newstalk App. You can also listen to Newstalk live on newstalk.com or on Alexa, by adding the Newstalk skill and asking: 'Alexa, play Newstalk'.

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“What did the council decide on item 42?” — answered with the speaker and the moment.