Bupropion (Wellbutrin)

Bupropion (Wellbutrin)

Bupropion is an dopamine and noradrenaline re-uptake inhibitor and works as an antidepressant. Meaning it works on dopamine and noradrenaline rather than serotonin, which is what makes it different from almost everything else in its class. Most people are prescribed it for depression, smoking cessation, or seasonal affective disorder, but it gets used off-label for ADHD, low motivation, fatigue-dominant depression, and to rescue sex drive in people whose SSRIs have flattened it. The practical reasons people end up on it: it doesn't kill libido, it doesn't cause weight gain (often the opposite), and it tends to be activating rather than sedating.
If you're choosing between bupropion and an SSRI, the trade-off is roughly this: bupropion preserves sex drive, energy, and weight but is less effective for anxiety and carries a small but real seizure risk at higher doses. SSRIs are better for anxiety and panic but commonly blunt libido and add weight over time. For people whose depression looks like low energy, low motivation, anhedonia, oversleeping, and brain fog, bupropion is often the better fit. For people whose depression is driven by anxiety or rumination, it's usually not.

Deep-dive

Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI). It blocks the dopamine transporter (DAT) and norepinephrine transporter (NET), which keeps more of those two neurotransmitters in the synapse for longer. It has essentially no effect on serotonin, which is why its side effect profile diverges so sharply from SSRIs. It's also a negative allosteric modulator of nicotinic acetylcholine receptors, which is the mechanism behind its smoking cessation effect, separate from any antidepressant action.
A lot of bupropion's clinical effect actually comes from its metabolites, particularly hydroxybupropion, which has higher affinity for NET than the parent drug and circulates at higher plasma concentrations. The drug is metabolised primarily by CYP2B6 in the liver. People with reduced CYP2B6 activity (genetic variants or co-administered inhibitors) accumulate more parent drug, which can shift the side effect profile.
Depression. Efficacy is roughly equivalent to SSRIs and SNRIs in head-to-head trials. A meta-analysis comparing bupropion XL to venlafaxine found similar response and remission rates, with bupropion causing significantly less sexual dysfunction. A systematic review of bupropion as an antidepressant confirmed efficacy across MDD populations and noted its differentiated profile on weight and sexual function. Where it tends to underperform: severe anxious depression with prominent rumination. Where it tends to overperform: depression with hypersomnia, low energy, and anhedonia.
Smoking cessation. Bupropion was the first non-nicotine pharmacotherapy approved for quitting smoking and remains a workhorse. In a French multicentre RCT, 6-month abstinence rates were 31% on bupropion versus 16% on placebo. In a 1,524-person Group Health trial in real-world primary care settings, bupropion paired with even minimal counseling produced clinically meaningful 12-month quit rates. Effects appear independent of whether the smoker has a history of depression and seem to work via reducing craving and withdrawal rather than mood.
Seasonal affective disorder. Bupropion XL is the only antidepressant licensed specifically for SAD prevention. Three large prevention RCTs in 1,042 patients found that starting bupropion XL in autumn (before symptoms appear) cut recurrence rates roughly in half compared to placebo. A Cochrane review graded the evidence as moderate quality. The practical protocol is to start 150-300 mg in the autumn before symptoms hit and taper off in early spring.
ADHD. Used off-label, especially in adults who don't tolerate stimulants or have comorbid depression, anxiety, or substance use issues that make stimulants unwise. A meta-analysis of randomised trials in adults found bupropion superior to placebo. The original Wilens trial found 52% of adults on bupropion were rated 'much improved' or 'very much improved' versus 11% on placebo. The honest summary: it works, but less reliably and less powerfully than stimulants. It's a second-line option, useful when stimulants aren't.
Sexual function. This is one of bupropion's most distinctive features. Unlike SSRIs, which cause sexual dysfunction in roughly 30-70% of people taking them, bupropion's rate of sexual side effects is not significantly different from placebo. It's also actively used as an add-on to rescue SSRI-induced sexual dysfunction, with reasonable evidence it helps. In nondepressed women with hypoactive sexual desire disorder (HSDD), open-label trials showed roughly 29% response rates. A 2022 systematic review and meta-analysis found the pooled effect across HSDD trials wasn't statistically significant on its own, but the dose-response signal was meaningful: lower doses (150 mg) outperformed higher doses (300 mg) for sexual desire specifically. So while it's not a guaranteed fix, it's one of the few options that doesn't make things worse and sometimes makes things noticeably better.
Weight. Bupropion is one of the only antidepressants associated with weight loss rather than gain. The combination drug Contrave pairs bupropion with naltrexone for obesity. The COR-II Phase 3 trial in 1,496 overweight and obese adults showed 6.4% weight loss at 56 weeks versus 1.2% on placebo, with about half of treated participants hitting at least 5% weight loss. The bupropion-only effect on weight is more modest but consistently downward in monotherapy depression trials.
Cognition and energy. The dopaminergic and noradrenergic profile is why bupropion tends to feel activating rather than sedating. Many people report sharper focus, better motivation, and reduced fatigue within the first few weeks, often before mood lifts. It's more effective than SSRIs at improving hypersomnia and fatigue in depression, which is a clinically meaningful difference for the energy-depleted depression phenotype.
Women. Pharmacokinetic studies adjusting for body weight find no meaningful sex difference in bupropion exposure, though women do tend to have a longer half-life because antidepressants are lipophilic and women have proportionally more body fat. Efficacy in women is comparable to men, and the sexual side effect advantage holds across sexes. The HSDD evidence above is specifically female. There's a meaningful prescribing imbalance, bupropion is prescribed roughly 3-4 times more often to men than women for depression, partly because of historical concerns about interactions with hormonal contraceptives and partly because the weight and sexual side effect profile is often pitched as a male preference. It's a perfectly reasonable choice for women too. Pregnancy data are limited, so most clinicians avoid initiating it during pregnancy unless the benefit clearly outweighs unknowns. It does pass into breast milk in small amounts.
Older adults. Pharmacokinetics are largely unchanged with age, but tolerability is more variable. Start lower and titrate slower. Bupropion is generally well-tolerated in older adults compared to TCAs and has a lower fall risk than serotonergic agents that cause orthostatic hypotension.
Limits of the evidence. Almost all the long-term data is in depression and smoking cessation. ADHD trials are mostly 6-10 weeks and underpowered. HSDD trials are small and heterogeneous. Long-term safety data beyond 1-2 years is limited. The seizure risk gets quoted often, but in absolute terms it's roughly 0.1% at standard doses (under 300 mg/day) and rises to about 0.4% at 450 mg/day, which is a real but small effect at therapeutic doses.

Dosage:

  • Standard starting dose (XL/extended-release): 150 mg once daily in the morning for 4-7 days, then 300 mg once daily. This is the target dose for most people on it for depression, SAD, or off-label uses
  • Maximum dose: 450 mg/day. Above this the seizure risk rises sharply (roughly 10x at 600 mg). Don't exceed 450 mg without specific reason and clinical oversight
  • SR (sustained-release): 150 mg once daily for 3 days, then 150 mg twice daily, with the second dose taken before 3pm to avoid insomnia. Max 200 mg twice daily (400 mg/day)
  • Smoking cessation: 150 mg once daily for 3 days, then 150 mg twice daily for 7-12 weeks. Start the medication 1-2 weeks before your quit date so it's at full effect when you stop
  • SAD prevention: Start 150 mg/day in autumn before symptoms typically appear, increase to 300 mg/day after a week, continue through winter, taper to 150 mg for two weeks in early spring before stopping
  • HSDD or SSRI-induced sexual dysfunction: 150 mg/day SR or XL is often more effective than 300 mg for desire specifically, per the dose-response data. Higher doses can paradoxically worsen the desire response
  • Older adults: Start at 75-150 mg/day and titrate more slowly. Effects are unchanged but tolerability windows narrow
  • Timing: Always take in the morning. Bupropion is activating and late-day dosing reliably wrecks sleep
  • Don't crush or chew XL or SR tablets. This converts a slow-release formulation into an immediate-release dump and dramatically increases peak concentration and seizure risk. The empty tablet shell sometimes appears in stool with XL, this is normal
  • Onset: Activation, energy, and focus often improve within 1-2 weeks. Mood effects typically take 4-6 weeks at the target dose. Don't judge it before week 4
  • Stopping: Bupropion has minimal withdrawal compared to SSRIs and SNRIs because it doesn't act on serotonin. Most people can taper relatively quickly (over 1-2 weeks) without significant discontinuation symptoms

Here's what you can expect:

In the first week or two, the activating effects usually come first: more energy, better focus, less of the leaden fatigue that often comes with depression. Some people feel slightly wired, jittery, or anxious during the initial titration, especially if they're sensitive to stimulants. This usually settles by week 3-4 as the system adjusts.
Mood improvement is slower. Most people don't notice clear mood lift until weeks 4-6 at the target dose, and the trajectory tends to be gradual rather than dramatic. If you're someone whose depression presents as anhedonia, low motivation, and brain fog, bupropion often works well. If your depression is dominated by anxiety, panic, or obsessive rumination, it's less reliable and may not be the right fit.
Subjectively, people often describe bupropion as 'taking the floor out from under' rather than 'lifting the ceiling.' It restores baseline function, energy, and motivation without producing the emotional flattening that some people get on SSRIs. Sex drive is usually preserved or improved. Weight is usually stable or trends slightly down. Sleep can be hit or miss, insomnia is the most common complaint, especially in the first month.
For smoking cessation, cravings drop within the first week or two and the urge to smoke becomes meaningfully easier to ignore. Most people who succeed on bupropion describe it as 'taking the edge off' withdrawal rather than eliminating cravings entirely.

Side effects & risks:

  • Insomnia is the most common side effect, affecting roughly 30-40% of people. Take the dose in the morning. If insomnia persists past a few weeks, the XL formulation tends to cause less disruption than SR or IR
  • Dry mouth, headache, nausea, constipation are common in the first few weeks and usually settle. Headaches respond well to standard analgesics
  • Anxiety, jitteriness, restlessness especially in the first 2 weeks. This is the activation effect of NDRIs. If it doesn't settle, the medication may not be right for you
  • Seizures are the most serious risk. At doses up to 300 mg/day the risk is roughly 0.1%, rising to 0.4% at 450 mg/day, and roughly 10x higher above 450 mg. Risk factors that compound this: history of seizures, head injury, alcohol or benzodiazepine withdrawal, eating disorders, low electrolytes, concurrent medications that lower seizure threshold (tramadol, theophylline, certain antibiotics, antipsychotics)
  • Eating disorders are an absolute contraindication. In a 1988 trial in bulimic patients, 4 out of 55 had grand mal seizures, far higher than expected. The mechanism likely involves electrolyte disturbances combined with bupropion's lower seizure threshold. Active or prior anorexia nervosa or bulimia means do not use bupropion
  • MAOIs are an absolute contraindication. The combination can cause hypertensive crisis. Wait at least 14 days between stopping an MAOI and starting bupropion (or vice versa)
  • Suicidality warning applies to all antidepressants. People under 25 should be monitored closely in the first 1-2 months for emergence of suicidal thinking, agitation, or behavioural change. This is a class-wide effect, not specific to bupropion
  • Sexual side effects are uncommon, in fact bupropion is often used to treat sexual dysfunction caused by other antidepressants
  • Weight loss is common but usually modest (1-3 kg). Worth noting if you're underweight or have a complicated relationship with food
  • Drug interactions: Bupropion inhibits CYP2D6, which raises levels of drugs metabolised by that enzyme (some beta-blockers, tricyclics, certain antipsychotics, dextromethorphan, codeine). It's also metabolised by CYP2B6, so inhibitors of that enzyme (some antiretrovirals, ticlopidine, clopidogrel) raise bupropion levels
  • Pregnancy: Limited data. Most guidelines suggest avoiding initiation during pregnancy unless the benefit clearly outweighs the unknown. If already on it and stable, decisions get individualised
  • Breastfeeding: Passes into breast milk in small amounts. Generally considered compatible with breastfeeding, but worth a conversation with your prescriber
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Blood markers

Blood pressure, baseline before starting and rechecked at 4-6 weeks once you've reached your target dose. Bupropion can push BP up modestly, occasionally significantly, and the FDA explicitly requires monitoring. If you're already hypertensive or on stimulants, this matters more.
Liver enzymes (ALT, AST), baseline and at 3 months if you have any history of liver disease or are taking other hepatically metabolised medications. Bupropion is metabolised primarily by CYP2B6, and impaired liver function shifts the dosing significantly (halve the dose or extend the interval in moderate-to-severe hepatic impairment).
Sodium, particularly in older adults or anyone on diuretics. Hyponatremia is rare but a known cause of lowered seizure threshold.
TSH, optional but useful if you're treating fatigue-dominant or hypersomnic depression. Subclinical hypothyroidism mimics this presentation and won't respond to bupropion.
Most people on standard doses (150-300 mg/day) without other risk factors don't need extensive monitoring beyond blood pressure. The people who do need closer follow-up: anyone on 450 mg/day, anyone with cardiovascular history, older adults, anyone with hepatic impairment, and anyone combining bupropion with stimulants, nicotine replacement, or other medications that lower seizure threshold.
Prescription-only in most countries. Approved for depression, smoking cessation, and seasonal affective disorder; widely used off-label for ADHD, weight management, and sexual dysfunction.