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Does Cymbalta cause weight gain?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Jan 8, 2024.

Official answer



Cymbalta is more likely to cause weight loss than weight gain early in the first 8 to 9 weeks of treatment. A modest weight gain may occur after 8 months of treatment. In general, weight loss is minimal and may be due to temporary nausea or loss of appetite, some of the most common side effects of Cymbalta treatment.

Weight loss or weight gain was reported by at least 1% (1 out of 100) of adult patients in clinical trials conducted by the manufacturer. In children treated with Cymbalta, weight loss can be common, most likely due to gastrointestinal (stomach) side effects like decreased appetite, nausea and vomiting.

How much weight gain occurs with Cymbalta?

Significant weight gain with Cymbalta has been reported in some, but not all, longer-term studies.

  • After 34 weeks (8.5 months) of treatment, no significant weight change was seen in patients taking 40 mg twice a day of Cymbalta (0.7 kg) compared to a placebo (0.1 kg).
  • In contrast, in those taking Cymbalta 60 mg twice a day a weight gain of 0.9 kg (1.5 lb) was reported compared to a gain of only 0.1 kg (0.2 lbs) in the placebo group. Weight gain was suggested, but not proven, to be linked with higher doses.
  • In a 52-week, open-label study, Cymbalta-treated patients receiving 40 to 60 mg twice a day had a significant mean weight gain of 1.1 kg (2.4 lb) at the end of the study.

In the 34-week studies, a weight gain greater than 7% of the baseline weight (at the start of the study) occurred in 8.6% of patients taking Cymbalta 40 mg twice a day (186 patients), and in 12.8% of those taking Cymbalta 60 mg twice day (195 patients), compared to 5.7% weight gain with placebo (192 patients). Results with the higher dose of Cymbalta were statistically significant vs. placebo and suggest a dose-related effect.

How can I stop weight gain with Cymbalta?

Overall, weight gain for most people taking Cymbalta is modest. For many people taking antidepressants this weight gain is gradual and can be addressed by lifestyle changes with a modified diet and exercise.

In theory, appetite may improve when depression, anxiety or pain is treated, which may lead to weight gain in some patients. Appetite and weight changes are also common symptoms of depression itself.

Does Cymbalta cause weight loss?

Decreased or loss of appetite (anorexia) was reported in over 7% of patients (vs. 2% on placebo) in several studies and may contribute to weight loss during early treatment. In these pooled studies, no association was found between higher doses of Cymbalta and weight loss. Nausea (23%), decreased appetite (7%) and abdominal pain (5%) were also reported as common side effects in studies submitted to the FDA.

  • Cymbalta (duloxetine) was shown to be more likely to cause a weight loss than a weight gain in pooled studies over the first 8 to 9 weeks of acute treatment in adults.
  • Patients treated with Cymbalta had a mean decrease in weight of 0.5 kg (1.1 lb) compared to an increase of 0.2 kg (0.44 lb) for patients receiving placebo, a statistically significant effect.

Other serotonin and norepinephrine reuptake inhibitors (SNRIs) like Cymbalta are also reported to cause gastrointestinal side effects like decreased appetite, loss of appetite and nausea.

If Cymbalta causes nausea, you can try taking your dose with a small meal which may make the medicine more tolerable. Your doctor will probably start your treatment at a lower dose and gradually increase it to help limit this side effect. If you experience vomiting with Cymbalta, contact your healthcare provider.

Does Cymbalta cause weight loss in children?

In Cymbalta studies, weight loss was one of the most common side effects (≥5% and twice that of placebo) in children 7 to 17 years.

  • In children 7 to 17 years of age receiving Cymbalta in three 10-week studies for depression and anxiety, a ≥3.5% weight loss was reported in 14% of children taking Cymbalta compared to 6% of those on placebo (an inactive treatment).
  • Decreased weight (14%), decreased appetite (10%), nausea (18%), vomiting (9%), and diarrhea (6%) were reported as common gastrointestinal side effects, occurring in at least 5% of children in this age group.
  • In children, Cymbalta is approved to treat generalized anxiety disorder and fibromyalgia, but not depression.

Weight loss may be related to side effects such as nausea (18% vs. 8% placebo), abdominal pain (13% vs. 10% placebo), vomiting (9% vs. 4% placebo), diarrhea (6% vs. 3% placebo) and decreased appetite (10% Cymbalta vs. 5% placebo) in children. Taking the medicine with food may help to lessen nausea.

In a review of uncontrolled studies extended up to 6 months, children taking Cymbalta tended to return to a normal weight on average when compared to peers. Regular monitoring of weight and growth should be performed for children treated with Cymbalta.

Cymbalta is approved by the FDA to treat:

  • major depressive disorder (MDD) in adults
  • generalized anxiety disorder (GAD) in adults and pediatric patients 7 years of age and older
  • diabetic peripheral neuropathic pain (DPNP) in adults
  • fibromyalgia (FM) in adults and pediatric patients 13 years of age and older
  • chronic musculoskeletal pain in adults

Why does Cymbalta cause weight changes?

Studies show that serotonin and norepinephrine reuptake inhibitors (SNRIs) like Cymbalta are frequently associated with weight loss due to gastrointestinal (stomach) side effects like decreased appetite and nausea. Nausea (23%), decreased appetite (7%) and abdominal pain (5%) occur frequently.

Antidepressants may cause weight gain by interfering with neurotransmitters in the brain like serotonin or histamine that help control appetite. Blocking histamine may boost appetite and also lead to weight gain. Some antidepressants may cause sedation and fatigue that lower levels of activity and exercise which may result in weight gain. However, Cymbalta is more likely to cause insomnia than drowsiness.

Decreased appetite and weight loss have been observed in association with the use of selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) in general.

Some antidepressants, like paroxetine (Paxil), fluvoxamine (Luvox) or mirtazapine (Remeron) can lead to significant weight gain.

Other antidepressants, such as sertraline (Zoloft), fluoxetine (Prozac), or bupropion (Wellbutrin XL) are more weight-neutral. Venlafaxine (Effexor) and duloxetine (Cymbalta) are SNRIs that also have more limited effects on weight gain.

Tricyclic antidepressants, an older class of medicines used to treat depression, are well-known to be associated with weight gain.

Related: Cymbalta Side Effects (in more detail)

Medications found in the serotonin-norepinephrine reuptake inhibitor (SNRI) class include:

Significant weight loss or weight gain with any antidepressant treatment should be evaluated by your doctor. Your medicine, dose or schedule may need to be changed. Your doctor can choose among many alternatives in the antidepressant drug class if weight gain, weight loss or stomach side effects like nausea are a concern for you.

  • Hudson JI, Wohlreich MM, Kajdasz DK, et al. Safety and tolerability of duloxetine in the treatment of major depressive disorder: analysis of pooled data from eight placebo-controlled clinical trials. Hum Psychopharmacol. 2005 Jul;20(5):327-41. doi: 10.1002/hup.696
  • Goldstein DJ. Duloxetine in the treatment of major depressive disorder. Neuropsychiatr Dis Treat. 2007;3(2):193-209. doi:10.2147/nedt.2007.3.2.193
  • Wise TN, Perahia DG, Pangallo BA, et al. Effects of the antidepressant duloxetine on body weight: analyses of 10 clinical studies. Prim Care Companion J Clin Psychiatry. 2006;8(5):269-278. doi:10.4088/pcc.v08n0503
  • Nelson C, et al. Serotonin-norepinephrine reuptake inhibitors (SNRIs): Pharmacology, administration, and side effects. Up to Date. Revised Oct. 2, 2020. Accessed Jan. 17, 2022 at
  • Cymbalta (duloxetine) prescribing information. Revised Sept. 2021. Eli Lilly and Co. Indianapolis, IN. Accessed Jan. 17, 2022 at

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