Drug & supplement interaction

Yerba Mate + Methoxsalen

Methoxsalen brand names: Oxsoralen, Oxsoralen Ultra.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Methoxsalen falls into 2 drug categories that Yerba Mate can interact with; the most serious is rated minor. Theoretically, concomitant use of CYP1A2 inhibitors and yerba mate might increase levels and adverse effects of the caffeine in yerba mate.

Read the full interaction report
SeverityMinor
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Yerba Mate and Methoxsalen

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Yerba Mate interacts with whole categories of medication. Methoxsalen falls into 2 of those categories, so it can interact with Yerba Mate in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS

1 of 2

Why this applies to Methoxsalen

Methoxsalen falls under CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS — the group Yerba Mate interacts with.

Theoretically, concomitant use of CYP1A2 inhibitors and yerba mate might increase levels and adverse effects of the caffeine in yerba mate.
Yerba mate contains caffeine. Caffeine is metabolized by CYP1A2. Theoretically, drugs that inhibit CYP1A2 may decrease the rate of caffeine clearance and increase caffeine levels.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to keep in mind with this pairing: methoxsalen (Oxsoralen) can slow down an enzyme in your liver called CYP1A2, and that same enzyme is what your body uses to clear caffeine. Yerba mate is loaded with caffeine, so in theory the caffeine could linger longer and pile up a bit. That might leave you feeling jittery, restless, or wired, with a racing heart, trouble sleeping, or an upset stomach.

I'll be honest with you, this concern is theoretical, based on how the drug works rather than on real-world reports, so it's rated as minor. If you notice extra caffeine jitters, easing back on the mate usually settles things. Check with your pharmacist or doctor if you have questions.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. PubMed
  2. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed
Minor

METHOXSALEN (Oxsoralen)

2 of 2
Theoretically, methoxsalen might increase the levels and adverse effects of the caffeine in yerba mate.
Yerba mate contains caffeine. Methoxsalen reduces caffeine metabolism.
Severity Minor Likelihood Possible Evidence B

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to know about pairing yerba mate with methoxsalen (Oxsoralen). This isn't really about the methoxsalen building up. Instead, methoxsalen can slow down the enzyme in your liver that clears caffeine, and yerba mate is loaded with caffeine. So the caffeine from your mate may hang around longer and feel stronger than usual.

In plain terms, you might notice more jitteriness, a racing or pounding heart, trouble sleeping, or feeling wired and anxious. This interaction is considered minor and is mostly theoretical, so it's not an emergency. If you drink a lot of mate, just keep an eye on how you feel, and chat with your pharmacist or doctor about whether to ease back. Never change your methoxsalen on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mays, D. C., Camisa, C., Cheney, P., Pacula, C. M., Nawoot, S., and Gerber, N. Methoxsalen is a potent inhibitor of the metabolism of caffeine in humans. Clin.Pharmacol.Ther. 1987;42(6):621-626. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Yerba Mate Also Interacts With Other Medications

Yerba Mate has 8 major, 505 moderate, 572 minor known drug interactions in our database — the Methoxsalen one above is among them. If you take anything else, check it against the full list below.

Major 8 Moderate 505 Minor 572 No known interaction 1,745 (incl. Methoxsalen)
Taking anything else?

Check Another of Your Medications Against Yerba Mate

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

Everything else you take

See Every Supplement That Interacts With Methoxsalen

This page covers Yerba Mate only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methoxsalen page lists 48 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (moderate), Angelica Archangelica (moderate), Arrach (moderate) and Bergamot (moderate).

By severity: 1 major · 33 moderate · 14 minor.

From our pharmacist’s overview on the Methoxsalen page

“Methoxsalen (Oxsoralen) works by deliberately making skin sensitive to ultraviolet light to treat psoriasis and vitiligo, so its supplement list deserves an unhurried, serious read. Twenty of the 48 ingredients on file add photosensitizing effects of their own, bergamot oil among them, and that stacking can push a carefully dosed light…”

Reviewed by 2 · Jul 18, 2026

Open the Methoxsalen interaction page

One more smart check

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

We hold 68 real supplement products containing Yerba Mate, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Yerba Mate. Your product may carry other ingredients that interact with Methoxsalen too, on top of Yerba Mate — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Yerba Mate and Methoxsalen 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 Yerba Mate
Steady interest

#1,072 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Methoxsalen
Top half

#982 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.

Supplement

About Yerba Mate

What is Yerba Mate?

Yerba Mate
  • Energy and alertness
  • Weight loss
  • Mental focus
  • Digestive support
  • Antioxidant support

Yerba mate is a caffeine-containing herbal beverage from South America that is widely enjoyed for its stimulating, coffee-like effects. While it is rich in antioxidants and is being studied for weight, blood sugar, and cholesterol, strong human evidence for most health claims is limited. Drinking very hot mate over many years has been linked to higher risk of certain cancers, so enjoy it warm and in moderation.

Read the full Yerba Mate monograph & all interactions
Keep checking

Other Drugs & Yerba Mate

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

8Major
505Moderate
572Minor
1,744No known interaction
8 Major 505 Moderate 572 Minor 1,744 No interaction
Major

8 interactions

Moderate

505 interactions

Showing 60 of 505 moderate interactions — see all 505 on the Yerba Mate page.

Minor

572 interactions

Showing 60 of 572 minor interactions — see all 572 on the Yerba Mate page.

No interaction 1,744 drugs checked — show the list

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

Showing the 60 most looked-up of 1,744 medications checked with no known interaction — see the full Yerba Mate list.

See the full Yerba Mate interactions page
See every supplement checked against Methoxsalen, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Yerba Mate monograph › Uses, safety, and every drug interaction in one place Methoxsalen supplement interactions › Every supplement checked against Methoxsalen, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Yerba Mate and Methoxsalen Together: Common Questions

Can you take Yerba Mate with Methoxsalen?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Yerba Mate and Methoxsalen?
Methoxsalen belongs to more than one drug category, and Yerba Mate interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Yerba Mate and Methoxsalen interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Methoxsalen and Yerba Mate?

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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.