Educational information, not medical advice — ask your doctor or midwife.
Beard lichen (Usnea barbata) is a pale grey-green lichen that hangs in threads from tree branches. It is not a plant. It is a fungus and an alga living together as one body.
In the Nordic countries it was used as a wound pad. Dry handfuls were pressed onto cuts and sores. Today it turns up mostly as a salve base, an oil infusion or a tincture.
Its local names are naava (Finnish), skägglav (Swedish) and lahppu in Sami. These point to long use across the north.
Here is the honest verdict. Lab tests show usnic acid slows some bacteria, but there are almost no human trials on wounds. Long traditional use is not proof that it works, and it is not proof that it is safe.
One hazard stands out. Taken by mouth, usnea and products made from usnic acid have been linked to severe liver injury, including liver failure.
Almost everything known about how usnea acts comes from the lab, not from people.
In test tube studies, usnic acid slows the growth of several gram-positive bacteria. These include the Staph and Strep germs often found on skin. Whether this happens in a real wound has not been shown.
A dry lichen pad also works in a plain physical way. It is soft, it soaks up fluid, and it holds a dressing against the skin. That alone may explain part of what tradition saw.
In cell and animal studies, usnic acid also damages liver cells. It appears to upset the way cells make energy. This is the main reason it must not be swallowed.
Some lab work suggests it may calm swelling and slow certain fungi. These findings are early. They have not been tested on human skin in good trials.
Beard lichen is sold and used in a small number of simple forms.
The plainest is the dried whole lichen. It can be teased into a soft pad to cover a small cut. This is the form the old Nordic accounts describe.
Salves and oil infusions are the most common modern form. The lichen is steeped in oil or fat, strained, then set firm with beeswax. The result is a greasy balm for minor skin complaints.
Tinctures are alcohol extracts, sold in dropper bottles. Many labels suggest taking them by mouth. That use is not safe, and this page does not support it.
Powders and capsules also exist. Some are sold as fat-burning or weight-loss aids. Those products have been tied to serious liver harm and should be avoided.
You may also see usnic acid listed in deodorants, foot powders and toothpastes. It is used there as a preservative and odour control agent, at low levels.
Beard lichen has a long record as a wound covering across Scandinavia and Sami lands. Herders, hunters and woodsmen reached for what grew on the nearest spruce or pine.
Writers from the 1700s and 1800s describe it packed onto cuts, grazes and boils. It was also used on sore feet and chafed skin. Some accounts mention it for coughs and chest trouble.
In Sami practice it was one of several forest materials kept for first aid. Dry moss and lichen were both used to pad and soak a wound.
Later, lichen salves and usnic acid preparations were made in Nordic and German pharmacies. Some were sold as antiseptic ointments in the mid-20th century. Modern antibiotics and sterile dressings replaced them.
None of this history tells you how well it worked. It records what people did, not what it achieved.
Stop using it and see a doctor if a wound gets worse rather than better.
Get medical help the same day for any of these: - redness spreading out from the wound, or red streaks on the skin - pus, swelling, throbbing pain or a bad smell - fever or chills - a wound that has not started healing after about a week
Get urgent care if you have swallowed a usnea product and feel sick, lose your appetite, have pain under your right ribs, pass dark urine, or your skin or eyes turn yellow. These can be signs of liver injury.
Call emergency services for trouble breathing, swelling of the face or lips, or a rash spreading over the body after use.
In the EU and UK, usnea salves are sold as cosmetics, and usnic acid is allowed as a preservative at low levels. No usnea product is approved as a medicine.
In the United States it is sold as a supplement, and the FDA has warned about liver injury from products containing usnic acid.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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