Nicotine excessively mutates a cell’s DNA, according to researchers at the Virginia Bioinformatics Institute who have labeled the chemical a “formidable carcinogen” and say that nicotine-infused smoking cessation products, like e-cigarettes, may not be the safest way to help smokers quit.

Nicotine is one of 4,000 chemicals found in cigarette smoke. While many of these chemicals are recognized as carcinogens, nicotine has up until now only been considered addictive rather than carcinogenic. It is heavily used in smoking cessation products in patches, gum, and now in the increasingly popular electronic cigarette.

But according to the research, nicotine causes thousands of mutations called single nucleotide polymorphisms (SNPs) in exposed cells, compared with control cells that were not exposed. These patterns are similar to those identified in cells experiencing oxidative stress, which is a known precursor to cancer.

“These results are important because for the first time they directly measure large numbers of genetic variations caused only by nicotine, showing that nicotine alone can mutate the genome and initiate a cancer state. This is particularly timely since nicotine is used as a smoking cessation therapeutic,” said and Harold “Skip” Garner, director of the institute’s Medical Informatics and Systems Division.

Future studies will focus on understanding the effects of long-term exposure of nicotine.