Does Mirtazapine Have Iron in It? The Surprising Answer About Medication Ingredients

November 18, 2025 •

3 min read

While the active ingredient in mirtazapine is the compound mirtazapine itself, its tablet formulations often contain specific colorants made from iron oxides. This means that in certain dosages, mirtazapine tablets do have a small, non-medicinal amount of iron present, though it is not bioavailable for the body's iron needs. This element is included solely as an excipient for coloring purposes, not for any therapeutic effect.

Quick Summary

Mirtazapine tablets, particularly certain strengths, contain iron oxides as inactive ingredients for coloring, not therapeutic purposes. These colorants are non-medicinal and do not affect the body's iron levels or nutritional needs. Understanding excipients clarifies how medications are manufactured.

Key Points

Iron is Present in Some Mirtazapine Tablets as a Colorant: Certain doses of mirtazapine tablets, like 15 mg and 30 mg, use iron oxides (E172) to give them their distinct yellow or brownish-red color.
Iron Oxides are Inactive and Non-Medicinal: The iron found in these tablets is a pigment, not a therapeutic agent. It is not bioavailable and does not provide nutritional iron to the body.
Does Not Treat Iron Deficiency Anemia: Mirtazapine should not be mistaken for an iron supplement. It will not correct iron deficiency, and patients should rely on prescribed iron therapy if they are anemic.
Iron Colorants Aid in Dosage Identification: The use of different colored tablets for varying dosages is a standard manufacturing practice to help patients and caregivers easily distinguish between strengths.
Check Inactive Ingredients on the Package Insert: For precise information on the ingredients in your specific medication, including excipients like iron oxides, always refer to the package insert or consult your pharmacist.
Potential for Allergic Reactions is Rare: While highly purified and safe for most, allergic reactions to inactive ingredients, including colorants, are theoretically possible but extremely uncommon.

Mirtazapine's Ingredients: Active vs. Inactive

When you take a medication, it's easy to focus solely on the active ingredient—the substance that produces the therapeutic effect. However, a pill is made of many components, both active and inactive. In the case of mirtazapine, the active compound is the chemical mirtazapine, which functions as an antidepressant. The remaining ingredients, known as excipients, are added for a variety of reasons, including stability, texture, and appearance. It is within these inactive ingredients that iron is found in some mirtazapine formulations.

Iron Oxides: The Coloring Agents in Mirtazapine

The iron in mirtazapine tablets is not in the form of an iron supplement like ferrous sulfate. Instead, it is present as iron oxides, a type of mineral pigment used to give certain dosage strengths their characteristic color. For example, the 15 mg and 30 mg mirtazapine tablets are often colored with yellow iron oxide (E172), and the 30 mg tablet may also contain red and black iron oxides. The iron oxides serve as a visual identifier for patients and healthcare providers to distinguish between different dosages, helping to prevent medication errors. The 45 mg tablet, which is typically white, usually does not contain these iron oxide colorants.

The Role of Excipients in Drug Manufacturing

Excipients are a critical part of pharmaceutical manufacturing. They are selected for their inert properties and their ability to help in the production, administration, and preservation of the drug. Other common inactive ingredients found in mirtazapine tablets include:

Microcrystalline cellulose: A bulking and binding agent.
Croscarmellose sodium: A disintegrant that helps the tablet dissolve.
Lactose monohydrate: A filler and binder.
Magnesium stearate: A lubricant to prevent the tablet from sticking to manufacturing equipment.
Hypromellose and polyethylene glycol: Components of the film coating that makes the tablet easier to swallow.
Titanium dioxide: An opacifier and pigment.

Why This Type of Iron Does Not Affect Health

The iron from iron oxides is chemically distinct from the form of iron absorbed by the body. Because it is used as a pigment, it is not bioavailable and does not provide nutritional value. This means it will not contribute to the body's iron stores and is not a treatment for iron-deficiency anemia. It also does not carry the same risks as iron supplements, such as gastrointestinal side effects. For individuals with a true iron deficiency, mirtazapine does not serve as a source of replacement iron, and a proper iron supplement prescribed by a doctor would be necessary.

Potential Concerns for Patients

Some patients might be concerned about the presence of any metal in their medication, especially if they have a known sensitivity or allergy. However, iron oxides used in pharmaceuticals undergo rigorous purification to ensure they are safe for consumption. In very rare cases, individuals may experience an allergic reaction to an inactive ingredient, but this is not specific to iron oxides. The primary concern for most patients with iron deficiency should be that this medication does not address their nutritional needs. They should not rely on mirtazapine as a source of dietary iron.

Comparison of Mirtazapine Dosage Strengths and Colorants


Dosage Strength	Tablet Color	Active Ingredient	Inactive Colorants	Purpose of Iron Oxide
15 mg	Yellow	Mirtazapine	Yellow iron oxide (E172)	Visual identification
30 mg	Reddish-brown	Mirtazapine	Red and yellow iron oxides (E172)	Visual identification
45 mg	White	Mirtazapine	Titanium dioxide only	Visual identification

Conclusion: Iron in Mirtazapine is for Color, Not Health

In summary, the question of whether mirtazapine contains iron is answered by examining its inactive ingredients. For specific dosages, particularly the 15 mg and 30 mg tablets, iron oxides are used as pigments to create the distinctive color. This is a completely different form of iron than a dietary supplement and has no effect on the body's iron levels. Patients can be assured that the presence of iron oxide is a standard pharmaceutical practice for identification and is not related to any therapeutic or nutritional aspect of the medication. The active ingredient responsible for treating depression is still mirtazapine, and any concerns about iron deficiency should be discussed with a healthcare provider who can prescribe a suitable iron supplement.

[Disclaimer: This article provides information for educational purposes and should not be considered medical advice. Always consult with a qualified healthcare professional regarding any medical questions or concerns.]

Frequently Asked Questions

The iron in some mirtazapine tablets is in the form of iron oxide colorants, which are inactive ingredients. These pigments, like yellow and red iron oxides, are used to create the specific color of the tablet for identification purposes and have no medicinal effect.

No, the iron oxides used in mirtazapine are not absorbed by the body in a way that affects your systemic iron levels. They are not a source of nutritional iron and will not correct or cause iron deficiency.

No, the iron is an inactive ingredient, or excipient. The active ingredient is the compound mirtazapine, which works to treat depression. Inactive ingredients like iron oxides are used for manufacturing and cosmetic purposes.

No, not all strengths contain iron. For example, the 45 mg tablet is often white and lacks the iron oxide colorants found in the 15 mg and 30 mg tablets, which are typically yellow and reddish-brown, respectively.

Iron oxide in medication is a non-bioavailable pigment, meaning the body cannot absorb or use it. Iron supplements (e.g., ferrous sulfate) contain a form of iron that the body can absorb to treat iron-deficiency anemia.

Common inactive ingredients include microcrystalline cellulose, croscarmellose sodium, lactose monohydrate, magnesium stearate, hypromellose, polyethylene glycol, and titanium dioxide.

For most people, the inactive ingredients, including iron oxides, are completely safe. They are extensively tested for human consumption. If you have concerns, speak to your pharmacist or doctor, but the colorants themselves are not harmful.