Does duloxetine contain lactose? (+9 other constituents)

This article will explore whether duloxetine contains lactose. It will also discuss the effects of taking duloxetine while being lactose intolerant.

Furthermore, the article will provide tips on how to identify medications that contain lactose. It also mentions the other ingredients present in duloxetine capsules.

Does duloxetine contain lactose?

No, duloxetine does not contain lactose. The tablets of Cymbalta (duloxetine) are lactose-free and can be safely administered by individuals suffering from lactose sensitivities or intolerances [1]. However, it is important to discuss all your concerns about intolerances or allergies with your doctor and pharmacist.

What do duloxetine formulations contain?

Duloxetine (Cymbalta) is formulated in capsule strengths of 30 mg or 60 mg of duloxetine. Other than duloxetine hydrochloride, there are other additives in Cymbalta, including [1]:

  • Sugar spheres are used as a filler and help with the controlled release of the medication. 
  • Hypromellose is a semisynthetic polymer used as a coating for the capsules. 
  • Purified talc is used as a lubricant in the manufacturing process. 
  • Purified water is used as a solvent in the formulation. 
  • Sucrose is a sweetening agent. Diabetes patients or people who are sensitive to sugar should be cautious when taking duloxetine.
  • Hypromellose phthalate is another coating agent for the capsules. 
  • Triethyl citrate is used as a plasticizer for the capsule shell. 


  • Gelatin is used to make the capsule shell. Some people may be allergic to gelatin, so it is important to inform your doctor about your allergies. The presence of gelatin also makes it non-vegan, similar to other antidepressants like Effexor and escitalopram.


  • Titanium dioxide is a coloring agent, and brilliant blue FCF is also used as a coloring agent. Some people may be allergic to these coloring agents, so it’s important to consult with a healthcare professional if there are concerns about allergies or intolerances to any of these ingredients.

The effects of taking duloxetine and dairy in lactose-intolerant people

If someone who is lactose intolerant takes duloxetine and also consumes dairy, they may experience some of the following side effects:

Increased gastrointestinal side effects

When lactose-intolerant people consume lactose-containing foods or drinks, they can experience various side effects, such as bloating, gas, diarrhea, and abdominal discomfort.

Duloxetine can also cause stomach pain and diarrhea in some people, so it is important to limit your intake of lactose while taking duloxetine to avoid experiencing increased gastrointestinal side effects [2].

Increased weight loss side effects

Furthermore, while lactose intolerance itself does not directly cause weight loss, the associated gastrointestinal problems and diarrhea that occur after lactose consumption can decrease one’s appetite and indirectly cause weight loss.

Moreover, avoiding lactose-containing foods can potentially lead to decreased calorie intake, which may result in weight loss.

Duloxetine may also affect appetite in some people, leading to increased weight loss, especially in those with lactose intolerance.

However, this is not a common side effect of duloxetine, and weight loss does not occur in everyone with lactose intolerance. Thus, not everyone with lactose intolerance may experience this interaction [2].

Impact on mental health problems

Finally, lactose-intolerant people experience uncomfortable symptoms when they consume dairy, which can impact their overall well-being and mental health and lead to feelings of frustration or even anxiety. This can decrease the subjective effectiveness of duloxetine in enhancing mood and treating anxiety. 

If someone with lactose intolerance is worried about the reduced effectiveness of duloxetine, it is recommended to discuss any concerns related to mood or medication efficacy with a doctor.

How to avoid medications that contain lactose?

First of all, you should inform your doctor about your lactose intolerance and discuss lactose-free options with a pharmacist. They can help identify lactose-free alternatives. For example, it is important to know that sertraline contains lactose.

Additionally, it is recommended that you read the medication inserts and labels for any mention of lactose or lactose-containing ingredients. Some manufacturers may state whether their drugs are lactose-free. For instance, look for drugs that have phrases like “lactose-free” or “does not contain lactose” on the packaging.

If the label doesn’t provide enough information, you can always get back to a pharmacist and ask them about the presence of lactose in a specific formulation.

Furthermore, some websites contain information on lactose-free drugs, such as drug databases that are made to help lactose-intolerant people find appropriate medications.


In conclusion, based on my knowledge, duloxetine tablets are lactose-free. In my perspective, taking duloxetine while lactose intolerant can lead to increased gastrointestinal side effects and duloxetine-induced decreased appetite and weight loss. 

Additionally, I found that the uncomfortable symptoms associated with lactose intolerance may impact overall well-being and mental health, potentially reducing the subjective effectiveness of duloxetine in enhancing mood and treating anxiety.

To avoid medications containing lactose, I recommend informing your doctor about lactose intolerance and discussing lactose-free options with a pharmacist. Reading medication inserts and labels for lactose information and utilizing lactose-free drug databases can also help identify appropriate medications.

Furthermore, based on my research, I found that duloxetine formulations contain various additives, including sucrose, gelatin, titanium dioxide, and brilliant blue FCF. Individuals with allergies or sensitivities to any of these ingredients should take care and inform their healthcare provider.

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Dhaliwal JS, Spurling BC, Molla M. Duloxetine. [Updated 2023 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

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