Lexapro (escitalopram) causes side effects in most people during the first few weeks, with nausea, anxiety, insomnia, and fatigue being the most frequently reported. The good news: many of these early side effects fade as your body adjusts to the medication, typically within the first one to two weeks. Some effects, like sexual dysfunction and weight changes, can persist longer.
The Most Common Side Effects
Based on user-reported data from thousands of Lexapro patients, the side effects people experience most often are anxiety (17.2%), nausea (12.2%), insomnia (10.7%), tiredness (10.1%), sexual dysfunction (8.1%), headaches (7.9%), and weight gain (6.9%). Dry mouth, dizziness, and increased sweating also show up frequently. These numbers come from self-reported reviews rather than clinical trials, but they give a realistic picture of what people actually notice day to day.
Nausea, dry mouth, and insomnia tend to improve within the first week or two as your body adjusts. If you’re starting Lexapro, that initial stretch can feel rough, but pushing through those early days often pays off. Taking the medication with food can help with stomach upset, and your prescriber may suggest taking it in the morning if it disrupts your sleep, or at night if it makes you drowsy.
Sexual Side Effects
Sexual dysfunction is one of the most common reasons people consider switching antidepressants, and SSRIs like Lexapro are well known for it. Estimates of sexual side effects across SSRI users range from 22% to 54%, with some studies reporting rates as high as 73%. The wide range reflects the fact that many people don’t bring it up unless directly asked.
The specific problems differ by sex. In men, Lexapro commonly causes delayed ejaculation and can make it harder to achieve or maintain an erection. In women, the more typical pattern is reduced sex drive and difficulty reaching orgasm. These effects are dose-dependent, meaning higher doses generally make them worse. They’re also reversible: sexual function typically returns to normal after stopping the medication or reducing the dose.
Weight Gain
Weight gain on Lexapro is real, but it’s modest compared to many other antidepressants. A study highlighted by Harvard Health found that escitalopram was associated with an average gain of about 1.4 pounds at six months. That’s a population average, so individual experiences vary. Some people gain more, some gain nothing, and a small number actually lose weight (especially early on, when nausea suppresses appetite).
If you’re concerned about weight, it helps to know that Lexapro sits on the lower end of the weight-gain spectrum among antidepressants. The changes tend to be gradual, and staying aware of eating patterns during the first few months can make a difference.
How Lexapro Compares to Other SSRIs
Lexapro and sertraline (Zoloft) are the two most commonly prescribed SSRIs, and their side effect profiles look similar on paper. In user reviews, sertraline shows slightly higher rates of anxiety (18.0% vs. 17.2%) and slightly lower rates of sexual dysfunction (6.9% vs. 8.1%) and tiredness (7.2% vs. 10.1%). Lexapro edges ahead in overall satisfaction, with 66% of users reporting a positive experience compared to 64% for sertraline.
These differences are small enough that individual variation matters more than averages. What works well for one person may not for another, and side effect tolerability is often the deciding factor when choosing between SSRIs that are similarly effective.
Serious but Rare Reactions
Most Lexapro side effects are uncomfortable rather than dangerous. But there are two serious risks worth knowing about.
Serotonin Syndrome
Serotonin syndrome happens when too much serotonin builds up in the brain, usually because of drug interactions rather than Lexapro alone. The classic warning signs are a combination of three things: involuntary muscle movements (jerking, twitching, or tremors), changes in heart rate and blood pressure with heavy sweating, and confusion or agitation. Rapid heartbeat, fever, dilated pupils, and muscle rigidity can also appear. This is a medical emergency. The risk increases significantly if Lexapro is combined with other medications that raise serotonin levels, including certain migraine drugs, pain medications, and other antidepressants.
Increased Suicidal Thinking in Young People
Lexapro carries an FDA boxed warning about increased risk of suicidal thoughts and behavior in children and adolescents. In clinical trials, the rate of suicidal thinking in young people taking antidepressants was about 4%, compared to 2% on placebo. This risk is highest during the first few months of treatment and during dose changes. Families and caregivers of young patients should watch closely for unusual changes in mood or behavior, especially irritability, agitation, or worsening depression, and stay in close contact with the prescriber during those early weeks.
What Happens When You Stop
Lexapro carries a moderate risk of discontinuation syndrome, a set of withdrawal-like symptoms that can appear if you stop taking it abruptly. Symptoms typically begin within two to four days and can include flu-like feelings (fatigue, headaches, body aches, sweating), nausea, dizziness, burning or tingling sensations that some people describe as “brain zaps,” vivid dreams, and mood changes like anxiety or irritability.
Discontinuation syndrome is not dangerous, but it can be very uncomfortable and is sometimes mistaken for a relapse of depression or anxiety. The most reliable way to avoid it is to taper off the medication gradually rather than stopping cold turkey. If symptoms do appear, restarting Lexapro at the previous dose usually resolves them within 24 hours, and your prescriber can then set up a slower tapering schedule. How long the taper takes varies from person to person, but it’s generally a process of weeks to months rather than days.
A Realistic Timeline
The first one to two weeks are when side effects tend to hit hardest. Nausea, headaches, and sleep disruption are common during this window and often resolve on their own. Sexual side effects and weight changes are slower to emerge and can persist for as long as you take the medication. It’s worth noting that the therapeutic benefits of Lexapro also take time: most people don’t feel the full antidepressant effect for four to six weeks, which means there’s an awkward early period where you may be dealing with side effects before the medication is fully working.
If side effects haven’t improved after two to three weeks, or if they’re significantly affecting your quality of life, that’s a reasonable point to talk with your prescriber about adjusting the dose or considering alternatives. Many side effects are dose-dependent, and a lower dose sometimes preserves the benefits while reducing the problems.