The world's longest documented hair belongs to Xie Qiuping (China) at 5.627 m (18 ft 5.54 in) when measured on May 8, 2004. She has been growing her hair since 1973 from the age of 13.

That is really long hair, if i tried to grow it that long I would get frustrated and cut it off. That is a very long time to grow hair. what a great Guinness world record!