Tobacco-Specific Nitrosamines (TSNAs)
Created by tobacco itself. Exist nowhere else.
At a glance
- Also known as
- TSNA · NNN · NNK
- CAS number
- 16543-55-8 (NNN), 64091-91-4 (NNK)
- Toxicity
Very high
- Carcinogenic
- Yes — IARC Group 1
- In cigarette smoke
- 100-1000 ng total TSNA per cigarette (brand-dependent, DKFZ + Hoffmann)
- In vape aerosol
- trace amounts (depends on liquid origin and contamination)
What is Tobacco-Specific Nitrosamines (TSNAs)?
Tobacco-specific nitrosamines (TSNAs) are a group of cancer-causing compounds that occur exclusively in tobacco products — and in trace amounts in nicotine replacement products — and nowhere else in the human environment. The most important are NNN (N-nitrosonornicotine) and NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone). Both have been classified by IARC as Group 1 carcinogens since 2007.
Why is Tobacco-Specific Nitrosamines (TSNAs) in cigarettes?
TSNAs form already during drying and fermentation of tobacco leaves: nitrite from the soil reacts with nicotine and its breakdown products to form nitrosamine compounds. Burning during smoking produces additional amounts. Each cigarette delivers 100 to 1,000 nanograms of total TSNAs into the mainstream smoke, depending on brand and processing method — some US brands have significantly higher content than European ones.
What Tobacco-Specific Nitrosamines (TSNAs) does to your body — short term
TSNAs cause no noticeable acute symptoms — their action is purely genetic. Like benzo[a]pyrene, they're enzymatically converted in the body to reactive intermediates that bind directly to DNA and can trigger mutations. NNK is especially potent in the lung, NNN in the oral cavity and oesophagus.
What Tobacco-Specific Nitrosamines (TSNAs) does long term
NNK is considered one of the most important organ-specific lung carcinogens — animal studies in rats and mice show that NNK alone, in amounts far below what a smoker takes in over years, induces lung tumours. NNN is closely linked to cancers of the oral cavity, throat and oesophagus — the typical cancers in chewing and snuff tobacco consumers. In cigarette smokers, both TSNAs act simultaneously.
Where else do you know Tobacco-Specific Nitrosamines (TSNAs) from?
TSNAs exist in the human environment exclusively in tobacco products (cigarettes, cigars, chewing and snuff tobacco, snus) and as trace amounts in nicotine replacement products. There's no industrial use, no occurrence in food, no presence in ambient air beyond tobacco smoke. This makes them unambiguous markers: anyone with TSNA breakdown products in their urine has been exposed to tobacco smoke — passively or actively.
How it compares
For TSNAs there are no separate workplace exposure limits, because they're tobacco-specific and don't occur outside tobacco processing. The FDA has listed NNN and NNK since 2012 as „Harmful and Potentially Harmful Constituents“ and requires US tobacco manufacturers to report them quantitatively; a 2017 proposed NNN limit of 1 µg/g tobacco applies exclusively to smokeless tobacco products (snus, chewing tobacco) — not cigarettes. No binding EU regulation exists. The only reliable way to avoid TSNAs is to abstain from tobacco.
Workplace exposure limit: kein Arbeitsplatz-Grenzwert (tabakspezifisch, keine anderen Vorkommen)
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