Roll Call

“Usnea?”Here!usnea lichen, old man's beard

Plant

Hasn’t appeared in a scanned product yet.

As a supplement

Talk to your doctor or pharmacist.

Roll Call does not check drug interactions or assess personal safety.

Usnea is a lichen — a symbiotic organism of fungus and algae — that grows on trees and rocks. Supplement extracts are usually made from the whole lichen and contain usnic acid as a main compound of interest.

Why it’s used

Taken traditionally to support respiratory and skin health, often marketed as an antimicrobial botanical.

What the evidence says

There is no NIH Office of Dietary Supplements fact sheet for usnea, and no body of well-designed human trials establishing an effect from oral use. Most available data come from laboratory and animal studies of usnic acid, not from people taking usnea itself.

Where we looked

There was no paper to cite here, so this is the search instead — run it yourself and see what we saw.

  • PubMed: 62 records · searched September 2026"Usnea"[Title/Abstract] AND (review[pt] OR "safety assessment"[Title/Abstract] OR "risk assessment"[Title/Abstract] OR toxicology[Title/Abstract] OR toxicity[Title/Abstract] OR characterization[Title/Abstract] OR characterisation[Title/Abstract])
  • PubMed: 0 records · searched September 2026"Usnea"[Title/Abstract] AND ("dietary supplements"[MeSH] OR supplementation[Title/Abstract] OR supplement[Title/Abstract] OR supplements[Title/Abstract] OR "oral administration"[Title/Abstract]) AND (randomized controlled trial[pt] OR clinical trial[pt] OR meta-analysis[pt] OR systematic review[pt]) AND humans[MeSH]
  • PubMed: 361 records · searched September 2026"Usnea"[Title/Abstract]

This says what this database holds under these terms. It is not a finding that no research exists.

Context

Traditional use spans centuries in folk medicine across several continents, but this history does not substitute for controlled human study, which remains sparse.

Insufficient dataToo little has been studied to say either way.

Rumors

  1. Usnea is a powerful natural antibiotic that works against the bacteria that cause strep throat, bronchitis and infected cuts.

    Does not supporthealth and safety evidence

    Measured as a biomarker.

    Who’s saying this

    • Herbal Fusion — a brand: sells multifunctional all-natural skincare products
      How we know who this is
      • “Herbal Fusion is a brand dedicated to creating multifunctional all-natural skincare products for mindful, nature-oriented, multitasking people.” (their page)

  2. Usnea aids weight loss.

    Does not support — establishedhealth and safety evidence

    Measured as an outcome.

    Who’s saying this

    • Healthline — a publisher: health information publisher; part of RVO Health, backed by Red Ventures and UnitedHealth Group's Optum
      How we know who this is
      • “Healthline is a digital publisher and does not offer personal health or medical advice.” (their page)
      • “Healthline is part of RVO Health, a company backed by Red Ventures and UnitedHealth Group’s Optum.” (their page)

  3. Usnea causes liver failure.

    Supports — establishedhealth and safety evidence

    Studied in: adults taking oral usnic acid-containing weight-loss supplements.

    Measured as an outcome.

    Who’s saying this

    • Ashley Adamant — an individual
      How we know who this is
      • “I’m Ashley Adamant , the creator behind Practical Self Reliance , where I share my journey in homesteading , self-sufficiency , and sustainable living .” (their page)

  4. Usnea tincture cures urinary tract infections and yeast infections.

    Not gradedhealth and safety evidence

    Sources cited — no verdict reached.

    What was measured is not yet noted.

    Who’s saying this

    • Paul Wheaton — a platform — posts are by its users: permaculture and homesteading forums; also sells products such as DVDs, books and courses
      How we know who this is
      • “COPYRIGHT © Paul Wheaton , missoula, MT 1986-2026” (their page)
      • “Most folks that come here are interested in our permaculture and homesteading community.” (their page)

  5. Usnea boosts the immune system against bacterial and viral infections.

    Does not supporthealth and safety evidence

    What was measured is not yet noted.

    • Toxicity of Usnic Acid: A Narrative Review (Peer-reviewed) · Funded by National Funding for Centers of Excellence (Science Department, Roma Tre University-MIUR) (government) · Authors declare a conflict of interest
    • Usnic acid (Database) · Funding not checked

    Who’s saying this