Nicotine patches may have helped many to kick the butt, but these can be equally dangerous as smoking as nicotine itself is carcinogenic, a new study shows.

Nicotine is such a powerful carcinogen that nicotine-infused products designed to help people give up smoking may not be safe, the findings showed.

Nicotine is one of 4,000 chemicals found in cigarette smoke.

While many of these chemicals are recognised as carcinogens, nicotine has, until now, only been considered addictive rather than carcinogenic.

Nicotine exposure causes thousands of mutations in a cell's DNA and this could be a precursor to cancer.

"These results are important," Harold Garner from Virginia Bioinformatics Institute in the US was quoted as saying.

"This is because for the first time they directly measured large numbers of genetic variations caused only by nicotine, showing that nicotine by itself can mutate the genome and initiate cancer," Garner added.