Some people believe thymus extract can boost your immune system and fight off symptoms of allergies, asthma, and autoimmune disorders. Is there any truth to these claims?

Read on to learn what thymus extract is and which claims are backed by research.

Your thymus gland sits below your thyroid gland and above your heart. It’s pinkish-gray in color and shaped like two ovals.

The thymus is a unique gland in that it works before birth and throughout puberty. When you hit puberty the gland starts to shrink and fatty tissue replaces it. By the time you reach age 75, your thymus gland is usually nothing more than fatty tissue.

Although the thymus gland stops working pretty early on in life, it still fulfills several key purposes. The thymus is responsible for producing and releasing the hormone thymosin. This hormone is responsible for stimulating the production of T lymphocytes, or T cells for short. These immune system cells help to ward off infection in the body. Once produced in the thymus, T cells travel to your lymph nodes, where they fight infection.

Scientists also study T cells for their potential cancer-fighting abilities.

As you age, your thymus gland gets smaller and can become less effective.

Thymus extract is made from the thymus glands of cows, typically calves. It can also be synthetically produced. Note that there is a difference between thymus extract and extract from Thymus serpyllum. The latter comes from the thyme plant.

Since the thymus gland is an important part of the immune system in both animals and people, some people think thymus extract has medicinal benefits. They believe that consuming it can boost your immune system, helping you fight off various diseases.

The idea of using animal glands or organs for medicinal purposes is hundreds of years old. This “glandular therapy” is based on the belief that “like heals like.” For example, glandular therapists believe that consuming nutrients from an animal’s healthy liver can help repair your liver if it’s damaged.

In the 1900s, scientists began to look for active chemicals in organ foods that have health benefits. Scientists and manufacturers have since isolated many chemicals, such as thyroid extracts, estrogen, and cortisol. Thymus extract is one of the chemicals they’ve extracted.

Thymus extract is now sold as a dietary supplement. It’s also sold in a more purified form, called thymomodulin. Both varieties are available in capsule, pill, or liquid form at many health stores.

Some evidence suggests that thymus extract might help ward off respiratory infections, such as bronchitis. This research has focused on people prone to respiratory infections. Other reasons a person may take thymus extract include fighting off hay fever and sinusitis that can all affect the respiratory system.

Some asthma attacks are triggered by an overactive immune system. Some research suggests that taking thymomodulin helps reduce the severity of asthma attack symptoms. It may also help reduce the frequency of asthma attacks.

Some people have used thymus extract to treat autoimmune conditions, such as rheumatoid arthritis, eczema, hepatitis B, hepatitis C, and HIV/AIDS.

Research on these uses is still in its early stages. According to the U.S. Department of Veterans Affairs, preliminary studies have found that thymus extract may help treat hepatitis B and hepatitis C. Some of these studies have used an injectable form of thymus extract. However, many of these studies conducted in the mid- to late-1990s used small sample sizes. The Department of Veterans Affairs found some studies pointed to an effective link between taking thymus extract in combination with interferon. Interferon is an injectable medication that’s also used in treating cancer.

Their findings don’t necessarily demonstrate the effectiveness of oral supplements. Other studies have focused on oral supplements. More current research is needed to support the proposed uses of thymus extract in fighting autoimmune disorders.

Allergic reactions happen when your immune system treats an otherwise harmless substance as a threat. As a result, it goes into attack mode.

Some people believe that thymus extract may help calm rather than boost your immune system if you have food allergies. Thymomodulin may help prevent allergic reactions, reports a study from International Immunopharmacology.

Thymus extract is sometimes added to cosmetics and hair care products as an antiaging ingredient. The extract contains amino acids and peptides, which are thought to help keep the skin supple and smooth. Ingredients lists on skin care products may call bovine thymus “bovine collagen.” The extract is added to moisturizers, facial masks, and more.

No side effects from thymus extract have been reported. But it’s important to note that dietary supplements aren’t well regulated by the U.S. Food and Drug Administration (FDA). For example, they aren’t covered by regulations that ban the sale of food products from cows with mad cow disease. Also, the FDA doesn’t currently list registered skin care products that have thymus extract added to them, yet many exist on the market. For this reason, you should always use caution when buying thymus extract.

Talk to your doctor before trying thymus extract or any other dietary supplements. They can help you assess the potential benefits and risks.

More research is needed to explore the potential benefits and risks of taking thymus extract. Some studies suggest it may help prevent or treat certain conditions, such as respiratory infections and asthma.

Always check with your doctor before trying a new dietary supplement or alternative treatment. It’s possible that bovine extract could react adversely with a medication you may be taking. Don’t stop taking other medications in favor of thymus extract unless directed by a doctor.