Drug & supplement interaction

Usnea + Varenicline

Varenicline brand names: Chantix, Champix, Tyrvaya.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Usnea and Varenicline in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Varenicline states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Usnea and Varenicline

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Varenicline and Usnea in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Usnea at all — not against Varenicline, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Usnea safety at a glance

Usnea overall Use caution Topical use is generally better tolerated, but oral usnic acid has been linked to liver damage.
Pregnancy Avoid Not enough safety data; avoid use during pregnancy.
Breastfeeding Avoid Not enough safety data; avoid use while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Varenicline and Usnea? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Usnea and Varenicline May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on Additional detail

    Usnea

    “Orally, usnic acid, a constituent of usnea, has been associated with reports of hepatotoxicity. From July to December 2000 there were at least seven cases of acute hepatotoxicity in patients taking LipoKinetix, a product containing usnic acid as sodium usniate.”

    Usnea · Natural Medicines adverse-effect record, reported in fatigue.

    6 sources cited
    1. 7091. Favreau JT, Ryu Ml, Braunstein G, et al. Severe hepatotoxicity associated with the dietary supplement LipoKinetix. Ann Intern Med 2002;136:590-5. PubMed
    2. 81595. Durazo, F. A., Lassman, C., Han, S. H., Saab, S., Lee, N. P., Kawano, M., Saggi, B., Gordon, S., Farmer, D. G., Yersiz, H., Goldstein, R. L., Ghobrial, M., and Busuttil, R. W. Fulminant liver failure due to usnic acid for weight loss. Am.J Gastroenterol. PubMed
    3. 81600. Neff, G. W., Reddy, K. R., Durazo, F. A., Meyer, D., Marrero, R., and Kaplowitz, N. Severe hepatotoxicity associated with the use of weight loss diet supplements containing ma huang or usnic acid. J Hepatol. 2004;41(6):1062-1064. PubMed
    4. 81607. Hsu, L. M., Huang, Y. S., Chang, F. Y., and Lee, S. D. 'Fat burner' herb, usnic Acid, induced acute hepatitis in a family. J Gastroenterol.Hepatol. 2005;20(7):1138-1139. PubMed
    5. 81612. Arneborn, P., Jansson, A., and Bottiger, Y. [Acute hepatitis in a woman after intake of slimming pills bought via Internet]. Lakartidningen 7-11-2005;102(28-29):2071-2072.
    6. 81619. Sanchez, W., Maple, J. T., Burgart, L. J., and Kamath, P. S. Severe hepatotoxicity associated with use of a dietary supplement containing usnic acid. Mayo Clin Proc 2006;81(4):541-544. PubMed

    Varenicline

    Listed in the ADVERSE REACTIONS section of the FDA label for Varenicline. Read the label on DailyMed ›

  • Stomach pain / Tiredness / Nausea Additional detail

    Usnea

    Recorded for Usnea in the same Natural Medicines adverse-effect record shown under Liver problems above.

    Varenicline

    Listed in the ADVERSE REACTIONS section of the FDA label for Varenicline. Read the label on DailyMed ›

  • A skin rash Additional detail

    Usnea

    “Topically, usnea and its constituent, usnic acid, can cause allergic contact dermatitis with respiratory symptoms.”

    Usnea · Natural Medicines adverse-effect record, reported in dermatitis.

    3 sources cited
    1. 11720. Ingolfsdottir K. Usnic acid. Phytochemistry 2002;61:729-36.
    2. 81580. Mitchell, J. C. Allergy to lichens. Allergic contact dermatitis from usnic acid produced by lichenized fungi. Arch Dermatol 1965;92(2):142-146.
    3. 81632. Rafanelli, S., Bacchilega, R., Stanganelli, I., and Rafanelli, A. Contact dermatitis from usnic acid in vaginal ovules. Contact Dermatitis 1995;33(4):271-272. PubMed

    Varenicline

    Listed in the ADVERSE REACTIONS section of the FDA label for Varenicline. Read the label on DailyMed ›

Reported for Usnea but not commonly for Varenicline: yellowing of the skin or eyes and weight loss.

Effects for Varenicline come from the ADVERSE REACTIONS section of its FDA label; effects for Usnea come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Varenicline Products Have a Food Rule — Usnea Should Not Break It

At least one FDA label for a product containing Varenicline says to take it with food. If you take Usnea on an empty stomach out of habit, keep them separate — and take Varenicline with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Varenicline products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Varenicline tablets should be taken orally after eating and with a full glass of water.

From the Dosage and Administration section of the FDA label we read for Varenicline — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Varenicline

This page covers Usnea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Varenicline page lists 20 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (moderate), Coffee Charcoal (moderate), European Mandrake (moderate) and Glucomannan (moderate).

By severity: 1 major · 10 moderate · 9 minor.

From our pharmacist’s overview on the Varenicline page

“For anyone taking varenicline (Chantix, Champix, Tyrvaya) to quit smoking, this list earns real caution rather than a quick skim. Activated charcoal is the single entry rated major; it binds many medicines in the gut and can pull varenicline's blood levels down, and losing that support mid-quit is a genuine setback.”

Reviewed by 2 · Jul 18, 2026

Open the Varenicline interaction page

One more smart check

Taking Usnea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 138 real supplement products containing Usnea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Usnea. Even though Usnea itself has no known interaction with Varenicline, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Usnea and Varenicline Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Usnea
Top half

#637 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Varenicline
Top half

#1,238 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Usnea reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Usnea and Varenicline records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Usnea

What is Usnea?

  • Sore throat
  • Skin and wound care
  • Respiratory infections
  • Urinary tract support
  • Antimicrobial/antifungal
  • Immune support

Usnea is a lichen used in traditional herbal medicine, mainly for sore throats, skin infections, and as a general antimicrobial. Laboratory studies suggest its main compound, usnic acid, can fight bacteria and fungi, but good human studies are lacking. Oral use of concentrated usnic acid has been linked to serious liver injury, so caution is important.

Usnea barbata · Parmeliaceae · Whole lichen (thallus) · Tincture, capsules, tea, throat sprays, topical salves

An interaction check asks whether these two react with each other — it does not ask whether Usnea is a good idea for someone in your situation. Here is what our Usnea record says about it on its own.

Usnea: dosing

There is no well-established standardized dose for Usnea. Products vary widely in strength and in how much usnic acid they contain, which makes safe dosing hard to define.If you choose to use Usnea, follow the directions on the product label and do not exceed them.

From our Usnea monograph — the full record covers uses, side effects and every documented interaction.

Read the full Usnea monograph & all interactions
Medication

About Varenicline

What Is Varenicline Used For?

Brand names: Chantix, Champix, Tyrvaya

Varenicline tablets — sold under brand names including Chantix — are used to help adults quit smoking. They work as part of a structured smoking cessation program.

Tyrvaya (varenicline solution) nasal spray is a separate product used to treat the signs and symptoms of dry eye disease. It is not used for smoking cessation.

Most-Reported Side Effects for Varenicline

From FAERS, the FDA’s public side-effect reporting system (0 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Nausea 14,514 reports
Depression 8,686 reports
Abnormal dreams 7,841 reports
Anxiety 5,978 reports
Insomnia 5,620 reports
See full Varenicline drug information
Keep checking

Other Drugs & Usnea

Browse every other medication we’ve checked against Usnea — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Usnea References

The 10 references that drive our Usnea monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Favreau JT, Ryu Ml, Braunstein G, et al. Severe hepatotoxicity associated with the dietary supplement LipoKinetix. Ann Intern Med 2002;136:590-5. PubMed
  2. Ingolfsdottir K. Usnic acid. Phytochemistry 2002;61:729-36.
  3. Scirpa, P., Scambia, G., Masciullo, V., Battaglia, F., Foti, E., Lopez, R., Villa, P., Malecore, M., and Mancuso, S. [A zinc sulfate and usnic acid preparation used as post-surgical adjuvant therapy in genital lesions by Human Papillomavirus]. Minerva Gin
  4. Mitchell, J. C. Allergy to lichens. Allergic contact dermatitis from usnic acid produced by lichenized fungi. Arch Dermatol 1965;92(2):142-146.
  5. Durazo, F. A., Lassman, C., Han, S. H., Saab, S., Lee, N. P., Kawano, M., Saggi, B., Gordon, S., Farmer, D. G., Yersiz, H., Goldstein, R. L., Ghobrial, M., and Busuttil, R. W. Fulminant liver failure due to usnic acid for weight loss. Am.J Gastroenterol. PubMed
  6. Neff, G. W., Reddy, K. R., Durazo, F. A., Meyer, D., Marrero, R., and Kaplowitz, N. Severe hepatotoxicity associated with the use of weight loss diet supplements containing ma huang or usnic acid. J Hepatol. 2004;41(6):1062-1064. PubMed
  7. Hsu, L. M., Huang, Y. S., Chang, F. Y., and Lee, S. D. 'Fat burner' herb, usnic Acid, induced acute hepatitis in a family. J Gastroenterol.Hepatol. 2005;20(7):1138-1139. PubMed
  8. Arneborn, P., Jansson, A., and Bottiger, Y. [Acute hepatitis in a woman after intake of slimming pills bought via Internet]. Lakartidningen 7-11-2005;102(28-29):2071-2072.
  9. Sanchez, W., Maple, J. T., Burgart, L. J., and Kamath, P. S. Severe hepatotoxicity associated with use of a dietary supplement containing usnic acid. Mayo Clin Proc 2006;81(4):541-544. PubMed
  10. Rafanelli, S., Bacchilega, R., Stanganelli, I., and Rafanelli, A. Contact dermatitis from usnic acid in vaginal ovules. Contact Dermatitis 1995;33(4):271-272. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Usnea and Varenicline Together: Common Questions

Is it safe to take Usnea with Varenicline?
We do not list a known interaction between Usnea and Varenicline. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Usnea and Varenicline have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Usnea and Varenicline at the same time of day?
At least one FDA label for a product containing Varenicline says to take it with food. If you take Usnea on an empty stomach out of habit, keep them separate and take Varenicline with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Varenicline products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Varenicline interact with any supplements?
Yes. Varenicline has documented interactions with 20 supplements in our database — Usnea is not one of them. The Varenicline interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Varenicline and Usnea?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.