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Usnea Lichen Health Benefits and Side Effects

author avatar Dr. Eric Berg 08/31/2023

Usnea is a type of lichen that grows on trees and rocks in damp and humid environments.   

Also known as old man's beard, usnea lichen has been used in traditional medicine for centuries to support wound healing and as a natural remedy for upper respiratory tract infections. 

Let's look at usnea's health benefits and how you can use usnea lichen products safely to support your health and well-being. 

lichenized fungi

What is usnea lichen?

Usnea lichen typically grows on trees, rocks, and other natural surfaces in moist or humid environments such as forests, meadows, and coastal regions. Many different usnea species are found across the globe, including in Europe, Africa, and North America.  

Lichens are symbiotic organisms that consist of algae and fungi. While the fungus provides structure and protection, the algae produces food and energy through photosynthesis.

Usnea lichen is rich in usnic acid, which has been found to possess potent antimicrobial properties and may be effective against bacterial, yeast, and viral infections.

Usnea has been used for its natural antimicrobial properties for centuries, and it remains a popular herbal remedy for skin infections and is believed to aid weight loss. 

three lichen species

Ways to use usnea 

Usnea is a popular medicinal lichen used in traditional herbal medicine to promote wound healing and as a natural remedy for respiratory and urinary tract infections. 

Herbal tinctures are a convenient form of usnea lichen. Because alcohol-based tinctures make some poorly soluble lichen metabolites more available, they are amongst the most popular usnea products. 

You can apply usnea tincture directly to gums or skin, drink usnea tincture mixed with water or tea, or make a gargle solution to combat a sore throat and other mouth infections. 

Usnea also is milled into a fine powder and sold in capsule form. Because of its antimicrobial properties, usnea is often added to herbal formulas that promote immunity.  

Traditional Chinese medicine typically uses usnea in tea form. Usnea can be steeped in hot water, which releases usnea’s bioactive phenolic compounds that are thought to protect from viral and bacterial infections, including influenza and streptococcal bacteria.


Potential health benefits of usnea

Usnea contains several lichen constituents that have been studied for their health-promoting properties. These active constituents include usnic acid, diffractaic acid, evernic acid, and vulpinic acid.

Research suggests that these potent plant chemicals impact metabolic health, suppress microbial activity, and promote a strong immune system

Here are four potential health benefits of usnea.

1. May lower the risk of infections  

Research suggests that usnic acid is a powerful antimicrobial compound that inhibits the activity of microbes and significantly lowers the risk of bacterial and viral infections.

Usnic acid has been found to be effective against antibiotic-resistant Staphylococcus aureus. These staph bacteria have developed resistance to many antibiotic medications, and severe infection can pose significant health risks.   

Usnea also appears to be an effective remedy against human papillomavirus (HPV) infections when combined with zinc sulfate. 

2. May support weight loss

It’s not uncommon to find usnea lichen in weight loss-promoting dietary supplements. There is some evidence from animal studies that usnic acid increases cellular energy production and stimulates metabolic functioning, which may support weight loss. 

However, human trials have not confirmed usnea’s effect on weight loss. And, what’s more, some weight-loss supplements containing usnic acid caused liver failure and even death. 

The U.S. Food and Drug Administration (FDA) issued a statement warning the public of the health risks associated with taking usnea weight loss products. 

3. May promote wound healing 

Usnea contains several phytochemicals and phenolic compounds that promote wound healing and support skin health. 

Evernic acid and usnic acid are potent antimicrobial compounds that help to keep wounds free of microbes and lower the risk of infection. These acids also may stimulate the formation of collagen and skin cell renewal which is linked to quicker wound closing and skin healing.

4. May protect against cancer growth

Although cancer-related research has only been conducted in test tubes, evidence suggests that usnea’s phytochemicals have anticancer properties

Usnic acid, diffractaic acid, evernic acid, and vulpinic acid are all potent antioxidants that protect your cells from oxidation and damage by free radicals, which are metabolic by-products that can cause cellular damage and inflammation.

Free radicals significantly increase the risk of DNA damage linked to an increased risk of cancer. Usnea’s bioactive chemicals appear to inhibit free radical activity and trigger apoptosis, also known as programmed cell death, of cancerous cells.  

Woman reading product label

Possible side effects and risks of usnea

Usnea contains a chemical called usnic acid, also known as sodium usniate. Some people appear to be sensitive to usnic acid, and consuming usnea tea or tinctures can result in gastrointestinal issues, including nausea and diarrhea.

Although usnea is generally safe as a topical application, it may cause allergic contact dermatitis and other skin reactions.

There is evidence that a high intake of usnea lichen can cause liver disease. Excessive amounts of usnic acid can harm liver cells and cause acute hepatitis and even liver failure. In fact, the FDA received several reports of liver toxicity caused by weight loss diet supplements containing usnea. 

usnic acid preparation

Usnea dosage and tips

The appropriate dosage of usnea lichen will depend on the form in which it's taken.

Here are some general dosage recommendations for usnea lichen:

  • Tinctures: The standard dosage for usnea tincture is around 30 drops, taken twice daily for no longer than ten days.

  • Teas: Steep one teaspoon of dried usnea lichen in hot water for 10 to 15 minutes. It's not recommended to exceed three cups daily. 

  • Dietary supplements: The standard dosage for usnea supplements is one capsule taken with food three times daily. 

  • Topical applications: Usnea cream or ointments can be applied to the affected area as needed.

It's crucial to remember that usnea lichen isn't intended to be consumed in high doses, and it's important to follow instructions on the product label or to consult with a healthcare provider. 

lichen species usnea barbata

Key takeaways

Usnea is a type of lichen that has been used in herbal formulas for centuries. It’s high in usnic acid, a potent antiviral and antibacterial plant chemical. 

Usnea is typically used to support immunity, as a natural remedy for respiratory and urinary infections, and to soothe a sore throat. 

Excessive amounts of usnic acid are harmful and can cause liver disease. It’s crucial to follow product-label instructions and to avoid taking usnea for extended periods.



1. Is usnea an antiviral and antibiotic?

Yes, usnea has potent antiviral and antibiotic properties. 

Usnea lichen is rich in usnic acid, and research suggests that usnic acid has antimicrobial properties that may protect from aerobic and anaerobic microorganisms, including viruses and bacteria. 

2. What does usnea taste like?

Although edible, usnea lichen isn't considered food. The taste of usnea depends on its location, but it's generally described as unpleasant. Usnea teas and tinctures typically have a bitter and earthy flavor. 

3. Is usnea edible?

Yes, usnea lichen is edible, but it's not particularly pleasant to eat and can cause gastrointestinal issues. Usnea isn't considered a food fit for human consumption.    

4. How much usnea can I use?

That depends on the usnea product and its intended use. Because too much usnic acid is harmful to the liver and can cause acute hepatitis, it's important to read product labels and avoid excessive intake of usnea. 

To avoid side effects, taking usnea for extended periods isn't recommended. 

5. What are the side effects of usnea?

Excessive amounts of usnea can harm the liver and even cause liver failure. Research in animals found usnic acid-induced necrosis in isolated rat liver mitochondria, meaning that usnea can potentially trigger liver cell death. 

Some individuals are sensitive to usnic acid and other active constituents of usnea, resulting in a range of symptoms, including gastrointestinal issues, rashes, and allergic reactions. 

6. What are the benefits of usnea?

Usnea contains usnic acid, a potent antimicrobial compound that may lower your risk of viral and bacterial infections. It's also believed that phytochemicals in usnea stimulate wound healing and may be beneficial in reducing cancer risk. 

7. Is usnea the same as old man's beard?

Yes, usnea is commonly referred to as old man's beard due to its long, hair-like growths that resemble a beard. 

8. Where does usnea grow?

Usnea grows on trees, rocks, and other surfaces in damp and humid forests, meadows, and mountain areas. It can be found across the world and thrives in many different climates. 

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