No single antidepressant wins across every category of side effects, but a few consistently rank among the most tolerable. In the largest comparative analysis ever conducted, covering more than 116,000 patients across 522 trials, agomelatine, fluoxetine, escitalopram, sertraline, and vortioxetine stood out as the antidepressants people were least likely to quit because of side effects. The best choice for you depends on which side effects matter most, because each medication trades one set of problems for another.
The Most Tolerable Antidepressants Overall
A landmark 2018 analysis published in The Lancet ranked 21 antidepressants by “acceptability,” meaning how often patients stopped taking them for any reason, including side effects. In head-to-head comparisons, agomelatine, citalopram, escitalopram, fluoxetine, sertraline, and vortioxetine were more tolerable than the rest. On the other end, amitriptyline, clomipramine, duloxetine, fluvoxamine, reboxetine, trazodone, and venlafaxine had the highest dropout rates.
When researchers looked specifically at people who quit because of adverse events (not just lack of improvement), agomelatine was the only antidepressant that didn’t significantly increase the dropout rate compared to a placebo. Every other antidepressant pushed dropout rates 1.6 to 4.4 times higher than a sugar pill. That makes agomelatine unique on paper, though it comes with its own catch: it’s consistently linked to abnormal liver function tests and requires regular liver monitoring.
Sexual Side Effects
Sexual dysfunction is one of the most common reasons people want to switch antidepressants. SSRIs and SNRIs as a class are well known for reducing sex drive, delaying orgasm, or causing erectile difficulties. Among the widely prescribed options, bupropion stands apart. It works through a completely different mechanism than SSRIs, and clinical data consistently show it causes sexual side effects at rates similar to placebo.
Vortioxetine also appears to cause fewer sexual problems than traditional SSRIs. In a study of patients who had already developed sexual dysfunction on an SSRI, switching to vortioxetine led to measurable improvement. Nausea is its most notable downside, with about 4% of patients stopping the drug for that reason alone. Mirtazapine is another option that tends to spare sexual function, though it carries a higher risk of weight gain and sedation.
Weight Gain
A large target trial emulation study comparing weight changes across common antidepressants found meaningful differences at six months. Using sertraline as the benchmark, escitalopram caused about 0.4 kg more weight gain, while bupropion caused about 0.2 kg less. Those numbers may sound small, but they represent averages. Some individuals gain significantly more, especially on mirtazapine and older tricyclics like amitriptyline, which are well established as the worst offenders for weight gain.
If weight is a priority concern, bupropion is the clearest choice. It’s one of the only antidepressants associated with modest weight loss rather than gain. Fluoxetine tends to be relatively weight-neutral in the short term, though its effects can shift over longer use.
Sleep Disruption and Sedation
Antidepressants can disrupt sleep in two opposite directions: some cause daytime drowsiness, others cause insomnia. A 2023 network meta-analysis in the journal SLEEP mapped both problems across 21 drugs.
For daytime sedation, bupropion was the only antidepressant that actually lowered the risk compared to placebo, cutting it roughly in half. Nearly every other antidepressant increased somnolence to some degree, with mirtazapine, trazodone, amitriptyline, and fluvoxamine among the most sedating.
For insomnia, the picture flips. Bupropion, along with most SSRIs and SNRIs, increased the risk of insomnia compared to placebo. Amitriptyline was the only drug that significantly reduced insomnia risk. So if you’re already struggling with sleep, a mildly sedating option like mirtazapine or trazodone might actually help, while bupropion could make things worse. If you’re worried about feeling groggy during the day, bupropion has the clearest advantage.
Heart Rhythm Safety
Some antidepressants can slightly alter heart rhythm by prolonging something called the QT interval, which in rare cases raises the risk of dangerous heart rhythms. Among SSRIs, citalopram carries the most documented risk, and the FDA has placed dose limits on it for this reason. Escitalopram, its close chemical relative, also shows possible dose-related effects.
Fluoxetine, fluvoxamine, and sertraline all show low risk for QT prolongation at standard doses. Paroxetine appears to have the lowest risk of any SSRI for this particular concern. Bupropion and mirtazapine also have favorable cardiac profiles compared to older tricyclic antidepressants, which carry the most significant cardiovascular risks.
Stomach and Digestive Issues
Nausea is the single most common side effect across nearly all antidepressants that boost serotonin. SSRIs and SNRIs cause nausea in roughly 15 to 30% of patients in the first few weeks, though it usually fades. Vortioxetine is notably associated with nausea, especially at higher doses.
Bupropion, because it doesn’t act on serotonin, causes substantially less nausea and digestive upset than SSRIs. Mirtazapine also tends to be gentler on the stomach. If GI symptoms are your main concern, these two are the most reliable options for avoiding them.
Discontinuation Symptoms
How hard an antidepressant is to stop matters as much as how it feels while you’re on it. An early double-blind trial found withdrawal effects in 60 to 66% of patients stopping sertraline or paroxetine after about 11 months, compared to just 14% of those stopping fluoxetine. The difference comes down to how long each drug lingers in your body. Fluoxetine has a very long half-life, meaning it tapers itself naturally over days to weeks, cushioning the transition. Paroxetine and venlafaxine, by contrast, clear the body quickly and are widely considered the hardest antidepressants to discontinue.
If you’re concerned about eventually stopping your medication, fluoxetine’s built-in slow exit is a genuine advantage. Sertraline and escitalopram fall somewhere in the middle for discontinuation difficulty.
Matching the Medication to What Matters Most
Here’s how the practical trade-offs break down by concern:
- Sexual function: Bupropion causes the fewest sexual side effects. Vortioxetine and mirtazapine are also lower-risk options.
- Weight: Bupropion is the safest bet. Fluoxetine is relatively neutral. Mirtazapine and amitriptyline carry the highest risk.
- Daytime drowsiness: Bupropion is the least sedating. SSRIs like fluoxetine and sertraline are moderate. Mirtazapine and trazodone are the most sedating.
- Insomnia: Mirtazapine and amitriptyline are least likely to disrupt sleep. Bupropion and most SSRIs can worsen it.
- Nausea: Bupropion and mirtazapine cause the least GI upset. SSRIs and vortioxetine cause the most.
- Ease of stopping: Fluoxetine is the easiest to discontinue. Paroxetine and venlafaxine are the hardest.
- Overall tolerability: Escitalopram, sertraline, fluoxetine, and vortioxetine rank among the best tolerated in large comparative data.
Bupropion comes closest to a “least side effects” answer for most people, particularly if sexual dysfunction, weight gain, and sedation are the concerns driving your search. Its main downsides are a slightly elevated insomnia risk and the fact that it’s less effective for anxiety-predominant depression than SSRIs. Among SSRIs, sertraline, escitalopram, and fluoxetine offer the best balance of effectiveness and tolerability, which is why they remain the most commonly prescribed first-line options worldwide.