The World's Greatest Shave, running from March 11 to 13, encourages people to shave or colour their hair to support patients with blood cancers and to fund vital research.

The Cleveland District State High School Year 11 student usually spends more than two hours every morning washing, treating, conditioning, blow drying and styling her hair, as well as applying a range of other products such as heat protector, before-and-after- straightening sprays, waxes and more.

At school on Thursday, however, the hair-loving teenager will go "no blade" and lose it all, being left with only a shiny scalp, which she said her friends will sign.

"Cancer patients don't have a choice about how much hair they lose, so why should I?" Lannah said.

Having lost her grandmother, to whom she was very close, and a friend to cancer, Lannah is passionate about raising funds to help research the disease.

"I saw a lady who was bald and I wondered if that was her choice or if she had to be bald because of cancer and I thought, 'Why not do it for Nan?'," she said.

"I didn't really think of the whole cause at first. I just wanted to do it for Nan but now I want to raise as much money as I can."

Lannah said the feeling that came with "doing something to help" was "amazing".

"It's a cause we really need to help," she said.

Lannah's proud mother, Julie Gafa, said Lannah was "always there for the underdog".

"She has pity for the disadvantaged and she's got a big heart," Julie said.

Lannah has so far raised $1000 for the Leukaemia Foundation, with more pledges still to come.

She is registered on the World's Greatest Shave website www.worlds greatestshave.com, where people can make a donation.