Most people take Wellbutrin (bupropion) for 12 weeks to quit smoking, but the process starts about a week before you actually stop. You begin the medication while still smoking, set a quit date during the second week, and then continue taking it for roughly three months to stay smoke-free through the hardest stretch of withdrawal.
The Week Before Your Quit Date
You start taking bupropion about one week before you plan to put down cigarettes. This lead time lets the drug build up in your system so it’s already working when you face your first day without nicotine. For the first three days, the dose is one 150 mg tablet per day. Starting around day three, the dose increases to two 150 mg tablets per day, taken at least eight hours apart, typically one in the morning and one in the evening.
During this first week, you keep smoking as usual. That can feel counterintuitive, but the medication needs time to reach effective levels in your brain. Many people notice their cigarettes become less satisfying during this buildup period, which is actually a sign the drug is doing its job.
How Bupropion Works in Your Brain
Nicotine hijacks the brain’s reward system. When you smoke, nicotine triggers a flood of dopamine, the chemical that makes you feel pleasure and reinforcement. That’s why quitting feels so miserable: your brain has learned to rely on nicotine for that dopamine hit, and without it, you feel flat, irritable, and fixated on cigarettes.
Bupropion tackles this from two angles. First, it blocks 75 to 95 percent of the nicotine receptors in the brain’s reward center, so even if you do smoke, the usual rush is dramatically blunted. Second, it gently raises baseline dopamine activity on its own, which helps fill the gap that quitting leaves behind. The result is that cravings lose their intensity and withdrawal symptoms like low mood and difficulty concentrating become more manageable.
What the 12-Week Course Looks Like
The standard treatment lasts 12 weeks total. Here’s how that breaks down in practice:
- Week 1: Start taking bupropion while still smoking. Pick a quit date during week two.
- Week 2: Stop smoking on your quit date. The medication is now at full dose.
- Weeks 3 through 12: Continue taking two tablets daily. This is the maintenance phase, where the drug helps you ride out cravings and stay abstinent.
Some treatment courses run as short as 7 weeks, but 12 weeks is the most common recommendation. If you’ve been on the medication for 4 weeks and still can’t maintain any stretch of abstinence, continued use may not be effective for you, and it’s worth discussing alternative approaches with your prescriber.
Can Treatment Go Longer Than 12 Weeks?
Yes. Clinical trials have shown that bupropion can help prevent relapse when used for up to one year. The first few months after quitting carry the highest risk of slipping back, so some people stay on the medication well beyond the initial 12 weeks. This is especially common for heavy smokers or people who’ve relapsed in previous quit attempts. Your prescriber can help you decide whether a longer course makes sense based on how you’re doing at the 12-week mark.
Common Side Effects
The two most consistently reported side effects are dry mouth and trouble sleeping. Insomnia is common enough that taking your second dose in the late afternoon rather than the evening can help. Other side effects include headache, nausea, dizziness, constipation, anxiety, and excessive sweating. Most of these are mild and tend to ease after the first couple of weeks as your body adjusts.
Bupropion lowers the seizure threshold, which means it’s not safe for people with a seizure disorder, a current or past diagnosis of anorexia or bulimia, or anyone abruptly stopping alcohol or sedatives. If you’re taking another medication that contains bupropion (it’s also prescribed for depression under different brand names), you can’t add a second bupropion prescription on top of it.
Weight Gain After Quitting
One reason people hesitate to quit smoking is the weight gain that often follows. On average, people who quit gain about 2 to 3 kilograms (roughly 5 to 7 pounds) in the first 12 weeks and 4 to 6 kilograms (9 to 13 pounds) over the first year. Bupropion has a modest advantage here: it reduces post-cessation weight gain by about 0.8 kg compared to quitting without medication. That’s a small effect, but it’s slightly better than nicotine replacement therapy, which reduces gain by about 0.5 kg. It won’t eliminate weight gain entirely, but it takes some of the edge off.
How Bupropion Compares to Other Options
Bupropion is one of two non-nicotine prescription medications approved by the FDA for smoking cessation, alongside varenicline. Among the available options, varenicline is the most effective for helping people quit, followed by bupropion, then nicotine replacement products like patches and gum. That said, bupropion has advantages that make it a better fit for certain people. It’s particularly appealing for those who also experience depression, since it has antidepressant effects. It’s also a reasonable choice for people who prefer a pill over patches or gum, or for those who want some protection against post-quit weight gain.
Some prescribers combine bupropion with nicotine replacement therapy for people who need extra support. The medication works through entirely different pathways than nicotine patches or gum, so using them together can address cravings from multiple directions at once.