Heparin, Premarin, and More: These Medications Are Made With Animal Byproducts

When people think about how their medications are made, they typically think of different chemicals produced in a laboratory. This is true for many medications, but certain medications actually come from animals.

Animal byproducts are parts of animals that don’t come from cuts of meat you might find in the grocery store. Instead, they’re made from other animal parts. Traditional medicine practices — such as those dating back thousands of years in ancient China — sometimes involved animal byproducts in the form of tiger bones and snake bile. Today, these byproducts include animal parts such as fats, glands, and connective tissue.

In the U.S., several FDA-approved medications contain animal byproducts that are important for either their function and purpose (active ingredients) or manufacturing and production (inactive ingredients). Read on to learn more about popular medications that contain animal byproducts and how they can be safely used to treat different health conditions.

What common medication ingredients come from animals?

Hormones are the most common animal-derived active ingredient in medications. Hormones are chemical messengers that travel between different organs and tissues to perform important roles involved in growth and development, metabolism, and reproduction.

For example, early-day insulin products came from pork and beef. Animal insulins are no longer approved for use in the U.S., but they’re still used in some foreign countries. And several other hormones from animals are still used in U.S. medications today — those are discussed later.

Other medications contain inactive ingredients from animal byproducts. These are important for their production during the manufacturing process. Here are the most common animal-based inactive ingredients:

• Gelatin. This is a protein that’s often found in gel capsules — it may come from animal skin or bones (usually from beef or pork).

• Lactose. A type of sugar that comes from cow’s milk, lactose is sometimes used as a binder or filler in tablet medications.

• Glycerin (or glycerol). This can be used as a sweetener and may come from animal fats.

• Stearic acid. This ingredient is found in some tablets and capsules — especially controlled-release medications. It sometimes originates from animal fats, but it can also come from vegetable sources.

What popular medications are made with animal byproducts?

The table below lists some popular medications made with animal byproducts. This is not a comprehensive list. 

Do liquid medications contain animal products?

Many liquid medications contain glycerin, which may come from either animal fat or vegetable oils. Glycerin is an oily and clear liquid that adds thickness and sweetness to liquid medications. 

Unfortunately, medication labels often don’t specify whether the glycerin came from animals or vegetables. But, you or your pharmacist can contact the drug company directly to find out more information about the source.

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Is it safe to consume medications made with animal products?

In general, yes. All FDA-approved medications — including those that contain animal byproducts — undergo a strict approval process. They’re evaluated for safety and effectiveness before they become available for the public to use.

However, people with certain dietary restrictions or food allergies should still talk to their healthcare professional (HCP) before taking medications that contain animal byproducts. Medication ingredients originating from animals can cause allergic reactions in people who are sensitive to them. Make sure that all members of your healthcare team are aware of any allergies, intolerances, or dietary restrictions that you have.

Does the FDA regulate the use of animal products in medications?

Yes. The FDA regulates the safety of all approved medications — including those containing animal byproducts.

However, it’s not always obvious to consumers if a medication contains animal byproducts. There are ongoing efforts to raise awareness about medications containing animal byproducts, but the FDA doesn’t currently have recommended guidelines to alert people about animal-derived medications.

Good to know: In 2019, the FDA updated its policies to also provide regulations for medical devices that contain animal byproducts, such as certain heart valves used in open-heart surgeries.

Are there alternatives to common animal products in medications?

In several cases, yes. For instance:

• HCPs can prescribe a different anticoagulant for people needing to avoid pork-derived heparin. Some examples include warfarin (Coumadin), apixaban (Eliquis), and rivaroxaban (Xarelto).

• People who need to avoid horse-derived estrogens in Premarin can talk to their HCP about potential estrogen alternatives, such as estradiol (Estrace, Vivelle-Dot, others).

• Levothyroxine (Synthroid) is a synthetic thyroid hormone that can be used instead of desiccated thyroid hormones from pigs. Today, synthetic thyroid hormones are used as first-choice medications to treat hypothyroidism.

Unfortunately, there are no vegan or animal-free alternatives for some medications, including pancreatic enzymes, propofol, or fish oil capsules.

Are any medications vegan?

A vegan lifestyle is one that excludes animals and animal products as much as “practical and possible.” In general, medications aren’t considered vegan because they’re required to undergo animal testing during clinical development. This is an important step to assess their safety and effectiveness before humans use them.

That being said, times are changing. In the future, fully vegan medications may be available. In 2023, the FDA removed its rules that require animal testing for new medications. Drug companies are still working out ways of safely excluding animals from the medication-making process.

Promising new technologies may change how new medications are tested. For example, advanced computer models could predict how medications will behave in humans. And “organs on a chip” may be able to model how a medication might work in a real human. These advances can allow testing in a way that doesn’t put animals or people at risk.

Clinical studies aside, many medications are manufactured in a way that avoids using animal byproducts. Some organizations prefer to describe these medications as “animal-free” rather than vegan. Thanks to a voluntary certification process, you can see a list of vegan-friendly medications and supplements from an organization called VeganMed.

Why trust our experts?

Written by:

Nathan Williams, PharmD, RYT

Nathan is a clinical pharmacist, certified yoga instructor, and medical content writer. His clinical practice has spanned several sub-specialties including: emergency medicine, nutrition, and pediatrics.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Austin Ulrich, PharmD, BCACP

​​Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. Ulrich’s experience includes direct patient care in hospital and community pharmacies.

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