How many cigarettes a day a person smokes – and how hard it is for them to quit – is at least partly dependent on the CYP2A6 gene.
This article explains the function of the CYP2A6 gene, which is part of the CYP450 family of enzymes tasked with breaking down and eliminating substances in the body. Additionally, we will explore the genetic variants (check your raw genetic data) in the CYP2A6 gene and then cover ways to speed up or slow down the enzyme. Members will see their genotype report below, plus additional solutions in the Lifehacks section. Join today.
CYP2A6 is part of the CYP450 family of genes that code for detoxification enzymes. (Learn more about other detoxification genes.)
The CYP2A6 enzyme is involved in the breakdown (metabolism) of:
- tegafur (cancer drug)
- Letrozole (cancer drug)
- Efavirenz (antiretroviral)
- Artemisinin (antimalarial)
- valproic acid (antiepileptic, bipolar, migraine med)
- Pilocarpine (glaucoma and dry mouth)
Note that some drugs are metabolized through more than one CYP enzyme.
The estrogen hormone, estradiol, causes higher CYP2A6 activity, and women usually have a somewhat higher activity of this enzyme.[ref]
We don’t just produce CYP2A6 to break down chemicals and drugs. In the body, the CYP2A6 enzyme also breaks down retinoic acid and some steroid compounds.[ref]
While other enzymes can also break down nicotine, the primary way that your body metabolizes it (breaks it down) is through hepatic CYP2A6 (70–80%). Also important to note is that the major metabolite of nicotine, called cotinine, is exclusively metabolized by the CYP2A6 enzyme.[ref] So, the CYP2A6 enzyme is responsible for two steps in the body’s process of getting rid of nicotine.
When it comes to smoking, the CYP2A6 genetic variants impact the speed at which nicotine is metabolized.
Researchers link genetic variants of CYP2A6 that cause decreased enzyme activity with a lower level of dependence in smokers, making it easier for them to quit. Basically, the slower CYP2A6 variants make the effects of nicotine last longer, thus reducing the number of cigarettes smoked.
On the other hand, people with increased CYP2A6 enzyme activity have an enhanced metabolism of nicotine and are likely to smoke more cigarettes per day.[ref]
CYP2A6: Genotype Report
Grapefruit juice contains a substance that inhibits CYP2A6 enzyme activity. So be careful – especially if you have a slow variant of the gene – with combining grapefruit juice with any drug that is metabolized by CYP2A6.[ref]
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