Drug & supplement interaction

Oak Moss + Losartan Potassium

Losartan Potassium brand name: Cozaar.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Oak Moss and Losartan Potassium 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 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

Oak Moss and Losartan Potassium

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 Losartan Potassium and Oak Moss 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 Oak Moss at all — not against Losartan Potassium, 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.

Oak Moss safety at a glance

Oak Moss overall Use caution Oak moss is a recognized skin allergen and is not well studied as an oral supplement.
Pregnancy Possibly Unsafe When used orally. The constituent thujone shows evidence of uterine stimulant activity. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally. The constituent thujone shows evidence of uterine stimulant activity. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Losartan Potassium and Oak Moss? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Oak Moss and Losartan Potassium 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on Additional detail

    Oak Moss

    “Orally, usnic acid, a constituent of oak moss, 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.”

    Oak Moss · 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

    Losartan Potassium

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

  • An allergic reaction Worth acting on Additional detail

    Oak Moss

    “Topically, use of oak moss may cause contact sensitivity and allergic reactions in people with lichen and moss allergy. In patch testing, very late reactions have occurred, some as late as 27 days after application. Usnic acid, a constituent of oak moss, also can cause allergic contact dermatitis with respiratory symptoms.”

    Oak Moss · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    6 sources cited
    1. 4023. Dahlquist I, Fregert S. Contact allergy to atranorin in lichens and perfumes. Contact Dermatitis 1980;6:111-9. PubMed
    2. 4033. Goncalo S. Contact sensitivity to lichens and compositae in Frullania dermatitis. Contact Dermatitis 1987;16:84-6. PubMed
    3. 4034. Goncalo S, Cabral F, Goncalo M. Contact sensitivity to oak moss. Contact Dermatitis 1988;19:355-7. PubMed
    4. 4039. Thune P, Solberg Y, McFadden N, et al. Perfume allergy due to oak moss and other lichens. Contact Dermatitis 1982;8:396-400. PubMed
    5. 108403. Schubert S, Schnuch A, Bauer A, et al. Very late reactions in the patch test with fragrance mix I and oak moss absolute (Evernia prunastri, INCI): Data of the Information Network of Departments of Dermatology (IVDK). Contact Dermatitis 2022;86(1):54-57.
    6. 11720. Ingolfsdottir K. Usnic acid. Phytochemistry 2002;61:729-36.

    Losartan Potassium

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

  • Tiredness / Stomach pain / Nausea reported in 7.2% of FDA reports for Losartan Potassium Additional detail

    Oak Moss

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

    Losartan Potassium

    Listed in the ADVERSE REACTIONS section of the FDA label for Losartan Potassium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Dizziness reported in 4.9% of FDA reports for Losartan Potassium Additional detail

    Oak Moss

    “Orally, large amounts or long-term use of thujone-containing products, such as oak moss, may cause convulsions, restlessness, tremors, and vertigo (12).”

    Oak Moss · Natural Medicines adverse-effect record, reported in vertigo.

    1 source cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.

    Losartan Potassium

    Listed in the ADVERSE REACTIONS section of the FDA label for Losartan Potassium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash Additional detail

    Oak Moss

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

    Losartan Potassium

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

  • Vomiting Additional detail

    Oak Moss

    “Orally, large amounts or long-term use of thujone-containing products may cause vomiting (12).”

    Oak Moss · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.

    Losartan Potassium

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

Reported for Oak Moss but not commonly for Losartan Potassium: yellowing of the skin or eyes, kidney problems, anxiety or restlessness and seizures.

Effects for Losartan Potassium come from the ADVERSE REACTIONS section of its FDA label; effects for Oak Moss come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 89,498 voluntary FDA FAERS reports for Losartan Potassium that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Oak Moss in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally. The constituent thujone shows evidence of uterine stimulant activity.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Oak Moss or Losartan Potassium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Oak Moss or Losartan Potassium, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Losartan Potassium

This page covers Oak Moss only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Losartan Potassium page lists 253 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Grapefruit (major) and St. John's Wort (major).

By severity: 6 major · 205 moderate · 42 minor.

From our pharmacist’s overview on the Losartan Potassium page

“Losartan potassium (Cozaar) treats high blood pressure, and this is a list to respect, because six of its 253 supplement interactions carry a major rating. Most entries do one of two things.”

Reviewed by 2 · Jul 18, 2026

Open the Losartan Potassium interaction page

How much people look this up

Where Oak Moss and Losartan Potassium 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 Oak Moss
Steady interest

#1,305 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Losartan Potassium
Top 10

#6 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 Oak Moss reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Oak Moss and Losartan Potassium records this page draws on were last updated July 10, 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 Oak Moss

What is Oak Moss?

Oak Moss
  • Perfume base note and scent fixative
  • Aromatherapy and fragrance
  • Traditional antimicrobial use
  • Soaps and cosmetics fragrance

Oak moss is a lichen that grows on oak and other trees and is best known as a perfume ingredient prized for its earthy, woody scent. There is very little human evidence to support taking it for any health condition, and it is a well-known skin allergen, so it is mainly used externally in fragrances rather than as a dietary supplement.

Evernia prunastri · Parmeliaceae · Whole lichen (thallus) and its extract/absolute · Essential oil, absolute, extract, fragrance ingredient; occasionally tinctures

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

Oak Moss: dosing

There is no established safe or effective oral dose for oak moss. It is not a standard dietary supplement, and reliable dosing information from human studies does not exist.If you come across an oak moss product, follow the directions on the label and do not exceed them. Given the lack of safety data, oral use is generally not recommended.

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

Read the full Oak Moss monograph & all interactions
Medication

About Losartan

What Is Losartan Used For?

Brand name: Cozaar

Losartan tablets — available as branded Cozaar and several generic products — are used to treat high blood pressure (hypertension) in adults and children 6 years and older. Lowering blood pressure reduces the risk of strokes and heart attacks. Losartan tablets are also used to reduce the risk of stroke in people with high blood pressure who also have left ventricular hypertrophy (an enlarged left side of the heart). Note: evidence suggests this stroke-risk benefit may not apply to Black patients.

Losartan tablets are additionally approved to protect the kidneys in people with type 2 diabetes, high blood pressure, and signs of kidney damage (diabetic nephropathy). Arbli, the oral suspension form, shares these same approved uses.

Most-Reported Side Effects for Losartan Potassium

From FAERS, the FDA’s public side-effect reporting system (89,498 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 6,464 reports
Nausea 5,301 reports
Diarrhea 5,184 reports
Dyspnea 4,689 reports
Dizziness 4,429 reports
See full Losartan drug information
Keep checking

Other Drugs & Oak Moss

Browse every other medication we’ve checked against Oak Moss — 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
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked Oak Moss against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Oak Moss list.

See the full Oak Moss interactions page
See every supplement checked against Losartan Potassium, ranked by severity
Evidence & sources

Oak Moss References

The 16 references that drive our Oak Moss 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Dahlquist I, Fregert S. Contact allergy to atranorin in lichens and perfumes. Contact Dermatitis 1980;6:111-9. PubMed
  4. Goncalo S. Contact sensitivity to lichens and compositae in Frullania dermatitis. Contact Dermatitis 1987;16:84-6. PubMed
  5. Goncalo S, Cabral F, Goncalo M. Contact sensitivity to oak moss. Contact Dermatitis 1988;19:355-7. PubMed
  6. Thune P, Solberg Y, McFadden N, et al. Perfume allergy due to oak moss and other lichens. Contact Dermatitis 1982;8:396-400. PubMed
  7. Favreau JT, Ryu Ml, Braunstein G, et al. Severe hepatotoxicity associated with the dietary supplement LipoKinetix. Ann Intern Med 2002;136:590-5. PubMed
  8. Ingolfsdottir K. Usnic acid. Phytochemistry 2002;61:729-36.
  9. Mitchell, J. C. Allergy to lichens. Allergic contact dermatitis from usnic acid produced by lichenized fungi. Arch Dermatol 1965;92(2):142-146.
  10. 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
  11. 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
  12. 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
  13. 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.
  14. 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
  15. 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 Oak Moss and Losartan Potassium Together: Common Questions

Is it safe to take Oak Moss with Losartan Potassium?
We do not list a known interaction between Oak Moss and Losartan Potassium. 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 Oak Moss and Losartan Potassium have any of the same side effects?
Yes — our sources link each of them separately to 8 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.
Does Losartan Potassium interact with any supplements?
Yes. Losartan Potassium has documented interactions with 253 supplements in our database — Oak Moss is not one of them. The Losartan Potassium interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Oak Moss monograph Uses, safety profile, and every drug interaction in one place Losartan drug information The full plain-English guide to this medication Losartan Potassium supplement interactions Every supplement checked against Losartan Potassium, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 16 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Losartan Potassium and Oak Moss?

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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.