Drug & supplement interaction

Mullein + Cobicistat

Cobicistat brand name: Tybost.

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 Mullein and Cobicistat 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 Cobicistat 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Mullein and Cobicistat

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 Cobicistat and Mullein 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.

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.

Mullein safety at a glance

Mullein overall Use caution Generally well tolerated for short-term use, but human safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid There is not enough data to consider it safe while breastfeeding.

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

Still wondering about combining Cobicistat and Mullein? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Cobicistat

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cobicistat is filed under 2 classifications — cytochrome p450 3a4 (cyp3a4) inhibitors, oral drugs. Mullein has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (minor) — and none of Cobicistat’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Mullein Does Interact With Other Medications

Mullein has 122 minor known drug interactions in our database — Cobicistat isn’t one of them. If you take anything else, check it against the full list below.

Minor 122 No known interaction 2,708 (incl. Cobicistat)
Taking anything else?

Check Another of Your Medications Against Mullein

Covers the 2,830 medications we’ve checked against Mullein. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Mullein and Cobicistat May Share a Side Effect

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.

  • A skin rash Additional detail

    Mullein

    “Two case reports have described dermatitis, with positive patch tests, after topical exposure to the whole plant, or by occupational inhalation of plant dust. In the case of topical exposure, the patient also had positive patch tests to other plants.”

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

    2 sources cited
    1. 92839. Castro AI, Carmona JB, Gonzales FG, Nestar OB. Occupational airborne dermatitis from gordolobo (Verbascum densiflorum). Contact Dermatitis 2006;55(5):301.
    2. 97316. Flores Echaiz C, Al Ali A, Cao AQ, Sasseville D. Simultaneous contact dermatitis caused by Asteraceae and Verbascum thapsus. Contact Dermatitis 2017;76(5):316-8.

    Cobicistat

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

Effects for Cobicistat come from the ADVERSE REACTIONS section of its FDA label; effects for Mullein come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 20,779 voluntary FDA FAERS reports for Cobicistat 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.

How to take them

Some Cobicistat Products Have a Food Rule — Mullein Should Not Break It

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

2 DOSAGE AND ADMINISTRATION TYBOST must be coadministered with atazanavir or darunavir at the same time, with food, and in combination with other HIV-1 antiretroviral agents.

From the Dosage and Administration section of the FDA label we read for Cobicistat — 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.

From our Q&A

Questions About Mullein or Cobicistat

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Mullein or Cobicistat, 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 Cobicistat

This page covers Mullein only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cobicistat page lists 30 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Adrafinil (moderate), Cannabidiol (cbd) (moderate), Cannabinol (cbn) (moderate) and Cannabis (moderate).

By severity: 1 major · 19 moderate · 10 minor.

From our pharmacist’s overview on the Cobicistat page

“Activated charcoal is the one entry to understand first if you take cobicistat (Tybost). Charcoal soaks up drugs in the gut, and since cobicistat's entire job is boosting an HIV medicine to protective levels, blunting its absorption can put the whole regimen at risk.”

Reviewed by 2 · Jul 18, 2026

Open the Cobicistat interaction page

One more smart check

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

We hold 780 real supplement products containing Mullein, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Mullein. Even though Mullein itself has no known interaction with Cobicistat, 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 Mullein and Cobicistat 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 Mullein
Top 25%

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

29 days ago today
Medication Cobicistat
Steady interest

#2,335 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 Mullein reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Mullein and Cobicistat 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 Mullein

What is Mullein?

Mullein
  • Cough and chest congestion
  • Sore throat
  • Bronchitis and respiratory irritation
  • Earache (traditional ear oil)
  • Mild inflammation

Mullein is a traditional herbal remedy most often used as a tea or syrup to soothe coughs, sore throats, and respiratory irritation. High-quality human studies are lacking, so its benefits are not well proven, but it is generally considered low-risk for short-term use in healthy adults. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or have a medical condition.

Verbascum thapsus · Scrophulariaceae · Leaves and flowers (sometimes roots) · Tea (infusion), tincture, capsules, syrups, lozenges, and ear oil drops

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

Mullein: dosing

There is no official or standardized dose for mullein. The amount used varies widely between products and traditional recipes, such as teas, tinctures, capsules, and syrups.The safest approach is to follow the directions on the product label and not exceed the recommended amount. A well-made tea is typically prepared by steeping the dried leaves or flowers in hot water and straining well to remove the irritating plant hairs.

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

Read the full Mullein monograph & all interactions
Medication

About Cobicistat

What Is Cobicistat Used For?

Brand name: Tybost

Tybost (cobicistat) is not itself an HIV treatment — it works by slowing the breakdown of certain HIV medicines so they stay active in your body long enough to work. Specifically, Tybost is used to boost the HIV medicines atazanavir or darunavir (once-daily dosing) as part of a complete HIV-1 treatment regimen in adults and in children weighing at least 14 kg (about 31 lbs).

Tybost is not interchangeable with ritonavir (another booster) for all HIV medicines. It is not recommended with darunavir twice-daily, fosamprenavir, saquinavir, or tipranavir.

Most-Reported Side Effects for Cobicistat

From FAERS, the FDA’s public side-effect reporting system (20,779 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Bone density decreased 8,112 reports
Chronic kidney disease 4,754 reports
Renal injury 4,577 reports
Tooth loss 4,186 reports
Bone loss 4,107 reports
See full Cobicistat drug information
Keep checking

Other Drugs & Mullein

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

0Major
0Moderate
122Minor
2,707No known interaction
122 Minor 2,707 No interaction
Minor

122 interactions

Showing 60 of 122 minor interactions — see all 122 on the Mullein page.

No interaction 2,707 drugs checked — show the list

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

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Mullein list.

See the full Mullein interactions page
See every supplement checked against Cobicistat, ranked by severity
Evidence & sources

Mullein References

The 2 references that drive our Mullein 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. Castro AI, Carmona JB, Gonzales FG, Nestar OB. Occupational airborne dermatitis from gordolobo (Verbascum densiflorum). Contact Dermatitis 2006;55(5):301.
  2. Flores Echaiz C, Al Ali A, Cao AQ, Sasseville D. Simultaneous contact dermatitis caused by Asteraceae and Verbascum thapsus. Contact Dermatitis 2017;76(5):316-8.

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 Mullein and Cobicistat Together: Common Questions

Is it safe to take Mullein with Cobicistat?
We do not list a known interaction between Mullein and Cobicistat. 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 Mullein and Cobicistat have any of the same side effects?
Yes — our sources link each of them separately to one 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 Mullein and Cobicistat at the same time of day?
At least one FDA label for a product containing Cobicistat says to take it with food. If you take Mullein on an empty stomach out of habit, keep them separate and take Cobicistat with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Cobicistat products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Mullein and Cobicistat combination checked?
Interactions in our licensed database are recorded against drug classes. Cobicistat is filed under 2 classifications, and Mullein has documented interactions with 1 drug class — none of Cobicistat's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Mullein interact with any other medications?
Yes. Mullein has 122 documented drug interactions in our database — Cobicistat is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Cobicistat interact with any supplements?
Yes. Cobicistat has documented interactions with 30 supplements in our database — Mullein is not one of them. The Cobicistat 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

Mullein monograph Uses, safety profile, and every drug interaction in one place Cobicistat drug information The full plain-English guide to this medication Cobicistat supplement interactions Every supplement checked against Cobicistat, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cobicistat and Mullein?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.