Day 20 after quitting smokingToo many receptors

By Yevhenii, who smoked for 26 years · Updated 30 Oct 2026 · 2 min read

In shortYears of nicotine make the brain grow extra receptors, and in one study they were still raised at four weeks and back to normal between six and twelve weeks. A craving with no trigger is that hardware being dismantled, not weakness.

What's happening in your body

Long exposure to nicotine makes the brain grow extra nicotinic receptors. A smoker has noticeably more of them than a non-smoker, and they do not vanish when the nicotine does. In brain imaging of people who had stopped, receptor levels were still raised at four weeks and had come down to the level of never-smokers somewhere between six and twelve weeks.

At four weeks, the more receptors a person still had in one part of the brain, the stronger their craving was on the day of the scan. The study was small, and only six people were scanned at the latest point, so treat the dates as a guide rather than a timetable.

What to expect

This explains a puzzle. The drug left your body in three days, yet something physical still seems to be asking for it. That something is real and it is on a schedule. You are roughly a third to a half of the way through it. It also explains why a craving can arrive with no trigger at all, on a calm evening when nothing has happened.

There is hardware in your head that was built for a substance and is being dismantled, and it complains while that happens. A craving like that is not weakness and not a step backwards.

Try this

The next time a craving comes out of nowhere, name it to yourself as the receptors, and note the time until it fades.

What else you could do

Mark those unexplained cravings in the Diary over the next few weeks. If the picture from the study holds, they should thin out. Nicotine replacement works on exactly these receptors, so if they are giving you a hard time, a pharmacist can talk you through the options, and using it is not smoking. While you wait, the same things as before still help. A short walk, a glass of water, the minute of breathing in SOS.

Sources. Cosgrove KP, Batis J, Bois F, et al. Beta2-nicotinic acetylcholine receptor availability during acute and prolonged abstinence from tobacco smoking. Arch Gen Psychiatry, 2009.