1. Health
Send to a Friend via Email
You can opt-out at any time. Please refer to our privacy policy for contact information.

Discuss in my forum

What are TSNAs?


Updated September 08, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What TSNAs are:

Tobacco-specific N-nitrosamines (TSNAs) are known to be some of the most potent carcinogens present in smokeless tobacco, snuff and tobacco smoke.

TSNAs consist of four chemical compounds:
  • N-nitrosonornicotine (NNN)
  • 4-methyl-N-nitrosamino-1-(3-pyridyl)-1-butanone (NNK)
  • N-nitrosoanatabine (NAT)
  • N-nitrosoanabasine (NAB)
Two of these chemical compounds, NNN and NNK, have been classified as Group 1 carcinogens.

Where TSNAs come from:

While TSNAs exist in low concentrations in green tobacco, it is the process of fermenting and curing tobacco that produces high levels of TSNAs in smokeless tobacco as well as tobacco smoke.

Cancers associated with TSNAs:

TSNAs are highly toxic and linked to several cancers:There is a growing concern that TSNAs may be associated with cervical cancer, because these carcinogens have been found in large quantities in the cervical mucus of women who smoke.

More on the chemicals in tobacco:

Cigarette smoke is a toxic mixture of over 7,000 chemicals including 250 poisonous and 70 carcinogenic compounds.


Hoffman, D et al, "The biological significance of tobacco-specific N-nitrosamines: smoking and adenocarcinoma of the lung." Critical Reviews in Toxicology, 1996; 26(2): 199-211.
Accessed March 2008.

U.S. Department of Health and Human Services. Reducing the Health Consequences of Smoking: 25 Years of Progress. A Report of the Surgeon General 1989.
Accessed March, 2008.

Prokopczyk, B et al. "Identification of Tobacco-specific carcinogen in the cervical mucus of smokers and non-smokers." Journal of the National Cancer Institute, 1997 Jun 18;89(12):868-73.
Accessed March 2008.

International Agency for Research on Cancer. Agents Classified by the IARC Monographs, Volumes 1–100.
Accessed June, 2010.

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.