Lexapro contains one active ingredient: escitalopram oxalate, a selective serotonin reuptake inhibitor (SSRI). The rest of the tablet is made up of inactive ingredients that hold it together, help it dissolve, and form its outer coating. Here’s a full breakdown of what’s in each form of the medication and what those ingredients actually do in your body.
The Active Ingredient: Escitalopram
Escitalopram is the drug that does the therapeutic work. It’s a refined version of an older antidepressant called citalopram (Celexa). Chemically, escitalopram is the “left-handed” mirror image of citalopram, isolated because it binds more effectively to its target in the brain. This higher selectivity is why Lexapro was developed as a separate medication rather than simply being a rebranded version of its predecessor.
Lexapro tablets come in three strengths: 5 mg, 10 mg, and 20 mg. The 10 mg and 20 mg tablets are scored, meaning they have a line down the middle so they can be split in half. An oral solution was also FDA-approved at a concentration of 1 mg per milliliter, though it is not currently being marketed.
How Escitalopram Works in the Brain
When brain cells communicate, they release serotonin into the gap between neurons. Normally, the sending cell quickly reabsorbs that serotonin through a transporter protein, recycling it. Escitalopram blocks that transporter, so serotonin stays in the gap longer and continues stimulating the receiving cell. Over weeks, this sustained increase in serotonin activity helps regulate mood and reduce anxiety.
What makes escitalopram unusual among SSRIs is that it also binds to a second spot on the same transporter protein. This “allosteric” binding locks the drug onto the transporter more tightly, making its blockade more complete. The result is a cleaner, more targeted effect on serotonin compared to many other antidepressants in the same class.
Once in your system, escitalopram is processed by the liver and has a half-life of roughly 27 to 32 hours, meaning it takes about a day and a half for your body to clear half of a dose. This is why it’s taken once daily and why effects linger for several days after stopping.
Inactive Ingredients in the Tablets
The inactive ingredients (sometimes called excipients) don’t treat depression or anxiety. They serve structural and functional roles:
- Microcrystalline cellulose and colloidal silicon dioxide: These form the bulk of the tablet and give it its shape and firmness.
- Croscarmellose sodium: A disintegrant that helps the tablet break apart in your digestive system so the drug can be absorbed.
- Magnesium stearate: A lubricant that prevents the powder from sticking to manufacturing equipment during production.
- Talc: Another flow agent used during the compression process.
The white film coating on the outside of each tablet contains hypromellose, titanium dioxide (which gives the tablet its white color), and polyethylene glycol. This coating makes the tablet easier to swallow and protects the active ingredient from moisture and light.
Lexapro tablets do not contain lactose or artificial dyes. The FDA label does not list gluten-containing ingredients, but if you have celiac disease or a severe sensitivity, checking directly with the manufacturer or your pharmacist about the specific lot is the safest approach, since suppliers of raw materials can vary.
Ingredients in the Oral Solution
The liquid form of Lexapro has a different set of inactive ingredients, designed to keep the drug dissolved, stable, and palatable. The full list includes sorbitol, purified water, citric acid, sodium citrate, malic acid, glycerin, propylene glycol, methylparaben, propylparaben, and natural peppermint flavor.
Sorbitol acts as a sweetener and stabilizer. Citric acid and malic acid adjust the pH and add a slight tartness. Methylparaben and propylparaben are preservatives that prevent bacterial growth in the liquid. If you have a known sensitivity to parabens, this formulation would be worth flagging. The oral solution is not currently on the market, but generic liquid versions of escitalopram may still be available with slightly different inactive ingredients.
What Lexapro Is Prescribed For
Lexapro is FDA-approved for two conditions: major depressive disorder (MDD) in adults and adolescents 12 and older, and generalized anxiety disorder (GAD) in adults. Doctors also prescribe it off-label for other anxiety-related conditions, though those uses haven’t gone through the formal FDA approval process.
The Boxed Warning on Suicidal Thinking
Every Lexapro label carries an FDA boxed warning, the most serious type of safety alert. In clinical trials, antidepressants including escitalopram were associated with increased suicidal thoughts and behavior in younger patients compared to a placebo. The numbers break down by age: among patients under 18, there were 14 additional cases of suicidal thinking per 1,000 patients treated. For ages 18 to 24, there were 5 additional cases per 1,000. Adults 25 to 64 actually showed 1 fewer case per 1,000, and adults 65 and older showed 6 fewer cases per 1,000.
This warning applies to the early weeks of treatment and dose changes, when mood can shift before the full antidepressant effect takes hold. It does not mean the medication causes suicidal behavior in most people, but it does mean close monitoring matters during the initial adjustment period, especially for younger patients.
Generic vs. Brand Differences
Lexapro is the brand name marketed by AbbVie (formerly Forest Laboratories). Generic escitalopram, widely available since 2012, contains the same active ingredient at the same dose. The differences are in the inactive ingredients. Generic manufacturers may use different fillers, binders, coatings, or dyes. If you’ve had an allergic reaction or sensitivity to a specific inactive ingredient, comparing the ingredient lists between brand and generic versions is worth the effort. Your pharmacist can pull the full excipient list for whichever generic your pharmacy stocks.