Days two and three are usually the worst of it, and it does get flatter after that. The NHS timeline says your pulse starts to settle within twenty minutes, carbon monoxide in your blood halves by eight hours and is down to a non-smoker's level by forty eight, and by seventy two hours your breathing is easier and your energy is up. The misery and the repair are running at the same time.
Here is the shape of those three days, and the short list of things to have in the house before you start.
Before the first morning
Do these the night before. All of them take minutes and all of them are things you will not manage on day two.
- **Fast-acting NRT in the pocket you actually use**, not in a drawer. Patch on before the day starts, since it does nothing for the first hour or so.
- **Get the smoking things out of the house.** Lighters, ashtrays, the emergency pack in the coat, the spare in the car.
- **Food in.** Being hungry and in withdrawal at the same time is a bad combination you can simply avoid.
- **Tell one person the date.** One is enough.
- **Book the free help.** A stop smoking service supplies the treatment and the weekly contact, and the NHS says you are "up to 3 times more likely to stop smoking for good" using both together.
Day one
The first few hours are often easier than people expect, which is its own trap. There is adrenaline in a decision, and it carries you until roughly lunchtime.
What to expect after that: cravings arriving in waves rather than as a constant, restlessness, a short fuse, and a strong urge to reorganise something. The first cigarette of the day is the one most people miss hardest, so the morning after the quit date is a specific hurdle rather than a general one.
By eight hours the carbon monoxide in your blood has halved. You will not feel that, but it is happening.
What to do with the evening: change it. The chair, the timing, the routine after dinner, all of it. Sitting in the exact spot at the exact hour where you always smoked and testing your resolve is the hardest available version of this.
Day two
This is the day people write about.
Expect the worst irritability of the whole quit, poor sleep or vivid dreams, a headache, and a rolling sense that the decision was stupid. That last one is the important one. The conviction that this was a mistake is itself a symptom, and it lifts.
At forty eight hours the NHS puts carbon monoxide at a non-smoker's level, your lungs beginning to clear mucus, and taste and smell starting to improve. The mucus part is why some people cough more in the first week rather than less, which feels like the opposite of progress.
Practical things for day two: do not schedule anything that requires patience, use the fast-acting NRT properly rather than rationing it, and keep the [craving routine](/guides/nicotine/getting-through-a-nicotine-craving) short and repeatable rather than heroic.
Day three
Usually still hard, and usually the day the slope turns.
The NHS puts seventy two hours at breathing becoming easier as the bronchial tubes relax, and energy increasing. Plenty of people do not feel energetic at all on day three, and that is not a sign the quit is going badly. Sleep is often still broken.
Day three is also when the reasoning gets clever. "I've proved I can stop, so one won't matter." That thought arrives on schedule for a lot of people, at the exact moment your defences are lowest.
What comes after the 72 hours
The rest of the fortnight, mostly. Smokefree.gov's summary is the most useful sentence written on this: "the worst withdrawal symptoms usually last less than two weeks, but that time can be really tough."
After that the cravings change character. They get shorter, further apart, and attached to places and routines rather than to your body. Then the milestone worth writing down: the NHS says that once you reach twenty eight days smoke-free, you are much more likely to quit for good.
The after-effects nobody warns you about, appetite, mood and the rest, are covered in [weight, mood and the things nobody warns you about](/guides/nicotine/weight-mood-and-the-things-nobody-warns-you-about).
What is hard, and what to ask about
We are not going to tell you from a web page which of your own symptoms are fine. What we will say is this: if something frightens you, or feels wrong rather than just difficult, ask a pharmacist, your stop smoking adviser or your GP. All three are free and all three would rather you asked. A pharmacist can answer most of it over a counter in two minutes.
Two specific things worth raising rather than sitting on. If low mood is deepening rather than lifting, that is a GP conversation, not something to get through alone. And if you take regular prescribed medicine, ask your pharmacist or prescriber whether stopping smoking changes anything about it. We are not listing which medicines, because we could not source a list we would stand behind, and the person with your prescription in front of them can tell you.
If you are in danger tonight, Samaritans is 116 123, any hour.
If you get through it and then slip on day four
That happens often enough to be ordinary. It does not undo the three days, and it does not mean you have to restart everything as a penance. [You had one, what now](/guides/nicotine/you-had-one-what-now) is the page for the next hour.
Common questions
Which day is the worst?
Most people find day two or day three hardest, with day one running on the adrenaline of having decided. After that it flattens, and Smokefree.gov puts the worst of withdrawal at under two weeks in total.
Why can I not sleep?
Broken sleep and unusually vivid dreams are common in the first days, and they are one of the reasons day two feels so bad. It is worth not judging anything about the quit on the basis of how you feel at four in the morning.
Should I take time off work?
Some people do and it helps, others find an empty week gives the cravings a clear run at them. If you can, avoid scheduling anything on days two and three that needs patience or a long fuse.
Why am I coughing more?
The NHS timeline has the lungs starting to clear mucus around forty eight hours, so coughing more in the first week is a known part of the picture rather than a sign of damage. If it worries you or persists, that is a normal thing to ask a GP or pharmacist about.
Does using a patch mean I am not really quitting?
No. NICE names nicotine replacement therapy among the options most likely to result in people stopping, and it is supplied free by a stop smoking service. What you are quitting is smoking, and the nicotine is dealt with second. There is more in [patches, gum, vapes: what actually helps](/guides/nicotine/nrt-vapes-and-what-actually-helps-you-quit).
Sources
- [NHS Better Health, Quit smoking](https://www.nhs.uk/better-health/quit-smoking/). The timeline of what happens at 20 minutes, 8 hours, 48 hours and 72 hours, and the 28 day milestone.
- [Smokefree.gov, Withdrawal](https://smokefree.gov/challenges-when-quitting/withdrawal). How long the worst withdrawal symptoms usually last.
- [NHS Stop Smoking Services help you quit](https://www.nhs.uk/live-well/quit-smoking/nhs-stop-smoking-services-help-you-quit/). The "up to 3 times more likely" figure and what a free service supplies.
- [NICE NG209 surveillance decision, February 2024](https://www.ncbi.nlm.nih.gov/books/NBK602607/). The treatments named as more likely to result in stopping smoking.
