What’s in Your Medicine? A Guide to Ingredients

Medications play a crucial role in our healthcare. They help to treat symptoms, manage chronic conditions, and even save lives. But have you ever wondered what your medications are made of and where their ingredients come from? 

Learning more about your medications can help you understand why certain ingredients are used and how different ingredients work together to make a drug effective.

What are medicines made of?

Most medications are made of a combination of active and inactive ingredients.

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Active pharmaceutical ingredients (also called APIs) provide the therapeutic effects of the medication. Inactive ingredients (also called excipients) are added to help with absorption, appearance, and more. The FDA reviews both the active and inactive ingredients in medications.

The specific ingredients and their amounts can vary depending on the medication and its intended use. The dosage form can also make a difference. For example, the ingredients used to make a suppository help release the active ingredient slowly as it melts inside the body. And modified-release capsules and tablets have ingredients that delay or prolong release of the active ingredient.

What are some common ingredients in medicine?

Today, there are many different ingredients in medications. Below are a few examples of both active and inactive ingredients.

Active ingredients

Some common active ingredients found in medicines include:

• Acetaminophen: a pain reliever and fever reducer. It’s found in medications such as Tylenol, cold and flu products, and prescription pain pills.

• Ibuprofen: a nonsteroidal anti-inflammatory drug (NSAID) used for pain relief and fever reduction. It’s found in medications such as Advil and Motrin.

• Aspirin: another NSAID used for pain relief and blood thinning. It’s found in medications such as Bayer aspirin and Aggrenox (aspirin/dipyridamole).

• Diphenhydramine: an antihistamine used for allergy relief and as a sleep aid. It’s found in medications such as Benadryl and ZzzQuil.

• Pseudoephedrine: a decongestant used for nasal congestion relief. It’s found in medications such as Sudafed.

Other popular active ingredients include:

• Atorvastatin: a statin medication that treats high cholesterol. It’s found in medications such as Lipitor and Caduet (amlodipine/atorvastatin).

• Lisinopril: a medication for high blood pressure and other heart conditions. It’s found in Zestril, Qbrelis, and combination blood pressure pills.

• Metformin: an oral diabetes treatment. It’s found in medications such as Fortamet, Glumetza, and combination diabetes pills.

Inactive ingredients

Some common inactive ingredients include the following:

• Binders help the medication hold its shape and size. Examples include gelatin and acacia.

• Fillers increase the volume of the medication. Examples include lactose and cellulose.

• Lubricants prevent the medication from sticking to machinery during manufacturing. Examples include magnesium stearate and stearic acid.

• Coatings improve the appearance and ease of swallowing the medication. Examples include gelatin and shellac.

• Preservatives prevent germs from growing in the medication. Examples include parabens and sodium benzoate.

• Color additives can help with the medicine’s appearance and aid with identification. Examples include yellow, red, and blue dyes.

It’s important to pay attention to a medication’s inactive ingredients, especially if you have allergies. That’s because some of them can cause allergic reactions. Examples include artificial dyes and polyethylene glycol.

Where do medicine ingredients come from?

Medication ingredients can come from different sources depending on the medication and its manufacturing process.

For example, active ingredients may come from plants, animals, or synthetic compounds. Biologic active ingredients come from a wide variety of sources, including microbes, humans, and animals. Inactive ingredients are often made from starches, sugars, and minerals.

Examples of medicines and their active ingredient sources include:

• Armour Thyroid is a desiccated thyroid extract for hypothyroidism. It comes from dried and ground thyroid glands of pigs.

• Premarin is conjugated estrogens for hormone replacement. It comes from the urine of pregnant horses.

• Estrace is a “bioidentical” type of estrogen called estradiol. It comes from a chemical extracted from soy or wild yam.

• Gene therapy is a type of biologic treatment. Ex-vivo gene therapy comes from your own cells.

How is medicine made?

Chemical-based medications are typically made by following a recipe. Active and inactive ingredients are measured and combined together into the final dosage form. Their structures are well defined and easier to copy.

Biologics, on the other hand, are much more complex. For example, some biologics are made by isolating and changing a component from a natural source, then using living cells to make copies of it. Because of this, there can be slight variations in the medication each time it’s made. But these small differences don’t affect how it works.

The safety and effectiveness of medications depend not only on their ingredients but also on their quality and purity. This is why the FDA has strict guidelines and requirements for the manufacturing and testing of medications.

Why trust our experts?

Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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