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What Is An Inactive Ingredient In OTC Medicine?

Why Are Inactive Ingredients Used?

Dr. Erin Williams Profile Photo

Written by Dr. Erin Williams on July 2, 2021

When purchasing a medication over the counter (OTC) at the local pharmacy, many patients check the list of active ingredients to see if the medication will help to treat their symptoms.

However, fewer people take the time to learn about the inactive ingredients that make up the majority of the medication. While these ingredients receive less attention, they can contribute to adverse effects in some patients, particularly those who have allergies or sensitivities to foods and medications.

So, what is an inactive ingredient in OTC medicine and what risks may be associated with these ingredients?

What is an inactive ingredient in OTC medicine?

All over the counter medications and prescription drugs contain two types of ingredients: inactive ingredients and active ingredients. The government provides definitions of both inactive ingredients and active ingredients under 21 CFR 210.3(b)(8).

As defined in 21 CFR 210.3(b)(8), an inactive ingredient is defined as any component of a drug product other than the active ingredient. Inactive ingredients comprise approximately 75 percent of the mass of the average medication, and these components contribute to shaping the look, feel, and taste of a medication.

An article authored by Harvard Medical School indicates that the average medication contains about nine different inactive ingredients.

In general, inactive ingredients are used for a number of different reasons, including:

  • Slowing the absorption rate of a medication
  • Making a medication taste better by masking the bitterness of active ingredients
  • Extending the shelf life of a medication by preventing the growth of fungi and bacteria
  • Binding the ingredients together to give the medicine a cohesive shape
  • Helping the body to absorb the drug more easily by combining with an easily digestible substance like a fatty acid

What is an active ingredient?

Most people are more familiar with the active ingredients of a medication as compared to the inactive ingredients of a medication.

Active ingredients are defined by 21 Code of Federal Regulations (CFR) 210.3, Current Good Manufacturing Practice in Manufacturing, Processing, Packing or Holding of Drugs, Part (b)(7) as any component of a drug product that is intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body of humans or animals.

Put more plainly, the active ingredients of a medication are the ingredients that have therapeutic benefit and work to relieve the symptoms of a medical condition. For example, if you’re experiencing a rash, the active ingredient in the medication would be the ingredient that reduces the itchiness and makes the rash disappear.

Why are inactive ingredients used in medications?

Inactive ingredients have many different purposes in medications despite the fact that they do not provide a therapeutic benefit.

Most drugs need inactive ingredients in order to work properly and maintain their form. Without these additional components, people may struggle to take their medication, the medication may not be absorbed properly, or the medication may have a shorter shelf life.

When formulating a medication, manufacturers use inactive ingredients for many different reasons, including:

  • To stabilize the active ingredients prior to ingestion
  • To extend the shelf life of the medication by preventing the growth of fungi and bacteria
  • To enhance the flavor of the medication to make it easier to swallow
  • To improve the appearance of the medication by adding color to make it more palatable
  • To act as binders between the ingredients of the medication
  • To act as buffers
  • To coat the surface of tablets, pills, and capsules to make them easier to swallow and less bitter
  • To act as a filler to increase the mass of the medication, making it easier to handle
  • To ensure that your body can absorb the medication effectively
  • To help the medication dissolve at the proper time in the digestive tract

Inactive ingredients are known to influence the color, size, shape, taste, and feel of a medication. Approximately 75 percent of the average medication is composed of inactive ingredients.

Most inactive ingredients do not have an effect on the human body. However, some ingredients that may be considered inactive ingredients in some circumstances may act as active ingredients, such as alcohol.

Are there any FDA requirements for inactive ingredients?

Active ingredients are tightly regulated by the U.S. Food and Drug Administration (FDA), while inactive ingredients are less restricted. However, the FDA does require that each medication list all of the inactive ingredients on the label of the product.

Consumers who are interested in understanding the inactive ingredients of a medication should check the label first.

While it can be easy to think that medications that have a similar appearance and have the same active ingredients, such as some non-steroidal anti-inflammatory drugs (NSAIDs), would have the same inactive ingredients, this is not always the case. That’s why it’s important to check the label every time you purchase a new medication.

Are inactive ingredients associated with any risks?

While the active ingredients of medications receive the most attention when it comes to side effects because these are the ingredients that actually treat your symptoms, inactive ingredients are also associated with a potential for adverse effects.

People with allergies to foods or medications, as well as those who have food sensitivities or intolerances, must be especially careful when choosing a medication product, as they may be more likely to experience adverse effects from inactive ingredients.

Although inactive ingredients are included in small quantities in most drugs, people who are highly sensitive to these ingredients or who consume multiple medications containing the same inactive ingredient can experience a reaction.

Two of the most common risks associated with inactive ingredients in medications include the potential for allergic reactions and digestive distress due to intolerances.

Allergic Reactions

Allergic reactions to the inactive ingredients in medications are considered to be rare. They can range in severity from mild to severe, with some allergic reactions being potentially life threatening or even fatal.

Presently, a total of 38 different inactive ingredients have been identified as having the potential to contribute to an allergic reaction. Inactive ingredients that are known to act as allergens include, but are not limited to:

  • Gluten
  • Lactose
  • Wheat starch
  • Peanut oil
  • Allura red dye
  • Brilliant blue dye
  • Sunset yellow FCF dye
  • Artificial sweeteners like aspartame, mannitol, sucrose, and saccharin
  • Sulfites
  • Benzoates
  • Oleic acid
  • Benzyl alcohol
  • Soya lecithin
  • Propylene glycol
  • Sorbitan trioleate

In its most severe form, an allergic reaction to inactive ingredients in a medication can result in a life threatening condition known as anaphylaxis. Anaphylaxis, which can potentially be fatal, causes swelling of the face, lips, and throat, difficulty breathing, and hives; a patient who experiences this condition must receive treatment right away. More mild symptoms of an allergic reaction include itching, skin irritation, and mild hives.

An estimated 93 percent of pills or capsules researched as part of one study were found to contain at least one potential allergen. Patients who have experienced adverse reactions or allergic reactions when taking medications that contain certain inactive ingredients may find that they react more favorably to medications that do not use artificial dyes or preservatives.

Digestive Distress

While allergic reactions to inactive ingredients are relatively rare, many more people are estimated to experience intolerances or sensitivities to certain ingredients. Most commonly, these individuals experience symptoms that include digestive distress, as evidenced by gas, bloating, or diarrhea.

The inactive ingredients most likely to cause digestive distress belong to a group of foods called FODMAPs, an acronym that stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. FODMAPs all contain sugars that some people may struggle to digest properly; these sugars are commonly used to mask the bitterness associated with many active ingredients and improve the taste of the drug, making it easier to swallow.

An estimated 55 percent of all oral medications include at least one FODMAP, with artificial sweeteners being the most common culprit.


An inactive ingredient in an OTC medicine is an ingredient that does not contribute to the relief of symptoms of a medical condition and instead influences characteristics like the taste, color, appearance, and feeling of a medication.

Inactive ingredients may cause allergic reactions or digestive distress even in small doses, particularly when consumed by patients who are allergic or highly sensitive. Patients who take a number of different medications are more likely to experience adverse effects like allergic reactions or digestive distress.