Which causes more weight gain, Celexa (citalopram) or Lexapro (escitalopram)?

Weight Gain Comparison: Celexa vs Lexapro

Lexapro (escitalopram) causes slightly more weight gain than Celexa (citalopram), though the difference is modest—approximately 0.3 kg more at 6 months.

Direct Comparative Evidence

The most robust head-to-head comparison comes from a large-scale 2024 target trial emulation study involving 183,118 patients across 8 U.S. health systems 1. This study provides the highest quality evidence for your question:

• Escitalopram (Lexapro) was associated with 0.41 kg greater weight gain at 6 months compared to sertraline as the reference 1
• Citalopram (Celexa) was associated with only 0.12 kg greater weight gain at 6 months compared to sertraline 1
• The difference between them is approximately 0.29 kg (about 0.6 pounds) over 6 months, with escitalopram causing more weight gain 1

Risk of Clinically Significant Weight Gain

Beyond mean weight change, the probability of gaining ≥5% of baseline body weight matters more clinically:

• Escitalopram increased the risk of ≥5% weight gain by 10-15% compared to sertraline 1
• Citalopram showed minimal increased risk for this threshold 1

Additional Supporting Evidence

An 8-month head-to-head trial comparing escitalopram with duloxetine found that escitalopram was associated with significantly more weight gain (+1.83 kg) compared to duloxetine (+0.61 kg) at 8 months 2. While this doesn't directly compare to citalopram, it confirms escitalopram's propensity for weight gain among SSRIs.

A 2011 study comparing escitalopram to nortriptyline found minimal weight change with escitalopram (average increase of 0.14 kg over 12 weeks, representing a 0.05-point BMI increase) 3. This positions escitalopram as relatively weight-neutral compared to tricyclics, though still associated with some weight gain.

Clinical Context Within SSRI Class

According to the American Gastroenterological Association, within the SSRI class 4:

• Paroxetine has the highest risk of weight gain among all SSRIs 4
• Fluoxetine and sertraline typically cause initial weight loss followed by weight neutrality with long-term use 4
• Escitalopram and citalopram fall in the middle, with escitalopram slightly worse than citalopram 1

Practical Clinical Algorithm

When weight is a concern in patients requiring antidepressant therapy 4:

1. First choice: Bupropion (if no contraindications such as seizure disorders or eating disorders) - consistently associated with weight loss 4, 1
2. Second choice: Fluoxetine or sertraline - weight-neutral to modest initial loss 4
3. Third choice: Citalopram - minimal weight gain 1
4. Fourth choice: Escitalopram - modest weight gain 1
5. Avoid: Paroxetine, mirtazapine, amitriptyline - highest weight gain risk 4

Important Caveats

• The absolute difference between citalopram and escitalopram is clinically small (less than 0.3 kg at 6 months) 1
• Individual patient responses vary considerably, and baseline weight status influences outcomes 3
• Medication adherence was low in the comparative study (28-41% at 6 months), which may underestimate true effects 1
• Weight monitoring should occur at baseline, monthly for 3 months, then quarterly during continued treatment 4