Join Here   |   Log In

CYP2A6: Breaking down nicotine and other medications

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:

  • nicotine
  • 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]

Nicotine metabolism:

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.

Quitting Smoking:

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

Members: Log in to see your data below.
Not a member? Join here.
Why is this section is now only for members? Here’s why…

Member Content:

Not a member?

Join Here



Grapefruit juice:

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]

Member Content:

Not a member?

Join Here

Related Articles and Topics:

CYP2C9: Breaking down prescription medications
Have you ever wondered why certain medications don’t work well for you? Genetic variants can change how fast or how slow the medication is broken down in your body. Learn how the CYP2C9 variants impact quite a few prescription medications.

Statins and Muscle Pain: Genes that impact myopathy
Statins are one of the most prescribed medications in the world. One side effect of statins is myopathy, or muscle pain and weakness. Your genetic variants are important in whether you are likely to have side effects from statins.

CYP1A1: Estrogen, hydrocarbons, air pollution
This phase I detoxification gene is important in the breakdown of the hydrocarbons produced in smoke and air pollution. It also affects the metabolism of estrogen.


About the Author:
Debbie Moon is the founder of Genetic Lifehacks. Fascinated by the connections between genes, diet, and health, her goal is to help you understand how to apply genetics to your diet and lifestyle decisions. Debbie has a BS in engineering from Colorado School of Mines and an MSc in biological sciences from Clemson University. Debbie combines an engineering mindset with a biological systems approach to help you understand how genetic differences impact your optimal health.