Drug & supplement interaction

Rooibos + Siponimod

Siponimod brand name: Mayzent.

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

Siponimod falls into 2 drug categories that Rooibos can interact with; the most serious is rated moderate. Theoretically, taking rooibos with CYP2C9 substrates may increase the effects of CYP2C9 substrates.

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

Rooibos and Siponimod

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

Why Are There 2 Interactions?

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

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 2

Why this applies to Siponimod

Siponimod falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Rooibos interacts with.

Theoretically, taking rooibos with CYP2C9 substrates may increase the effects of CYP2C9 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems inhibits CYP2C9 enzyme activity.
Severity Moderate 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

Your body relies on a liver enzyme called CYP2C9 to clear siponimod (Mayzent). Lab studies hint that rooibos may slow that enzyme down. If that happened in real life, siponimod could build up a bit more than expected, which might mean stronger effects and a higher chance of side effects like a slow heart rate, headache, dizziness, higher blood pressure, or changes in liver tests.

Here's the reassuring part: this is only a theoretical concern from test-tube research, not from people, and a cup or two of rooibos tea is very unlikely to cause trouble. Concentrated rooibos extracts would be more of a question mark. Since siponimod is dosed carefully based on your genetics, it's worth a quick chat with your pharmacist or neurologist before adding rooibos supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Siponimod also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, taking rooibos with CYP3A4 substrates may increase the effects of CYP3A4 substrates.
In vitro research shows that the methanol extract of rooibos leaves and stems strongly inhibits CYP3A4 enzyme activity.
Severity Moderate 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 situation with rooibos and Siponimod (Mayzent). Your body uses an enzyme called CYP3A4 to help break down siponimod. Lab studies (in test tubes, not people) suggest that strong rooibos extracts may slow this enzyme down. In theory, that could let more siponimod build up in your system, which might mean more side effects like a slower heart rate, headache, dizziness, higher blood pressure, or changes in liver tests.

I want to be honest with you: this is theoretical and based only on early lab work, not real patient cases. A cup or two of rooibos tea is very unlikely to cause a problem. Concentrated rooibos extracts or supplements are where I'd be more cautious. Either way, it's worth a quick chat with your pharmacist or doctor before adding them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fantoukh OI, Dale OR, Parveen A, et al. Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea (Aspalathus linearis) through Interaction with CYP, PXR, and P-gp. J Agric Food Chem. 2019;67(17):4967-4975.

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

Rooibos Also Interacts With Other Medications

Rooibos has 878 moderate known drug interactions in our database — the Siponimod one above is among them. If you take anything else, check it against the full list below.

Moderate 878 No known interaction 1,952 (incl. Siponimod)
Taking anything else?

Check Another of Your Medications Against Rooibos

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

Everything else you take

See Every Supplement That Interacts With Siponimod

This page covers Rooibos only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Siponimod page lists 190 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 3 major · 147 moderate · 40 minor.

From our pharmacist’s overview on the Siponimod page

“Siponimod (Mayzent) treats secondary progressive multiple sclerosis, and because its blood level depends heavily on two liver enzymes, this is a supplement list to respect. Most of these entries can nudge siponimod levels up or down; the three rated major are grapefruit, which raises them, St.”

Reviewed by 2 · Jul 18, 2026

Open the Siponimod interaction page

One more smart check

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

We hold 142 real supplement products containing Rooibos, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rooibos. Your product may carry other ingredients that interact with Siponimod too, on top of Rooibos — 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 Rooibos and Siponimod 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 Rooibos
Top half

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

29 days ago today
Medication Siponimod
Steady interest

#2,437 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 Rooibos

What is Rooibos?

Rooibos
  • Caffeine-free beverage
  • Antioxidant support
  • Heart health
  • Blood sugar support
  • Digestive upset
  • General wellness

Rooibos is a caffeine-free herbal tea from South Africa that is rich in antioxidants and generally considered safe as a beverage. While lab and early studies suggest possible benefits for heart health, blood sugar, and inflammation, strong human evidence is lacking for most medical uses. Enjoy it as a tea, but talk to your pharmacist or doctor before using concentrated extracts for health reasons.

Read the full Rooibos monograph & all interactions
Medication

About Siponimod

What Is Siponimod Used For?

Brand name: Mayzent

Mayzent (siponimod) is approved for adults with relapsing forms of multiple sclerosis (MS). This includes three specific types: clinically isolated syndrome (a first episode of MS-like symptoms), relapsing-remitting MS (periods of attacks followed by recovery), and active secondary progressive MS (a phase where the disease gradually worsens but still has active relapses).

It is taken by mouth once daily and is intended as a long-term treatment to reduce relapses and slow disease progression.

See full Siponimod drug information
Keep checking

Other Drugs & Rooibos

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

0Major
878Moderate
0Minor
1,951No known interaction
878 Moderate 1,951 No interaction
Moderate

878 interactions

Showing 60 of 878 moderate interactions — see all 878 on the Rooibos page.

No interaction 1,951 drugs checked — show the list

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

Showing the 60 most looked-up of 1,951 medications checked with no known interaction — see the full Rooibos list.

See the full Rooibos interactions page
See every supplement checked against Siponimod, 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
Rooibos monograph › Uses, safety, and every drug interaction in one place Siponimod supplement interactions › Every supplement checked against Siponimod, ranked by severity Siponimod drug information › The full plain-English guide to this medication 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 Rooibos and Siponimod Together: Common Questions

Can you take Rooibos with Siponimod?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Rooibos and Siponimod?
Siponimod belongs to more than one drug category, and Rooibos 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 Rooibos and Siponimod interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Siponimod and Rooibos?

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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.