Drug & supplement interaction

Bulbine Natalensis + Estrogen

Estrogen brand name: Estrogen.

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

Estrogen falls into 3 drug categories that Bulbine Natalensis can interact with; the most serious is rated moderate. Theoretically, Bulbine natalensis stem might reduce the levels and clinical effects of CYP1A2 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Bulbine Natalensis and Estrogen

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Bulbine Natalensis interacts with whole categories of medication. Estrogen falls into 3 of those categories, so it can interact with Bulbine Natalensis in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 3

Why this applies to Estrogen

Estrogen falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Bulbine Natalensis interacts with.

Theoretically, Bulbine natalensis stem might reduce the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that Bulbine natalensis stem extract slightly induces CYP1A2 mRNA expression and enzyme activity. Theoretically, this may increase the metabolism of CYP1A2 substrates; however, this has not been studied in humans.
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 gist for combining Bulbine natalensis with your estrogen. Part of how your body clears estrogen runs through a liver enzyme called CYP1A2. In lab studies (not people), this plant seemed to slightly speed that enzyme up. If it does the same in the body, your estrogen could be broken down a touch faster, which might mean weaker relief, so think returning hot flashes, night sweats, or vaginal dryness creeping back.

I want to be honest though: this is theoretical and only based on test-tube work, so it may not amount to much in real life. There's also separate concern about Bulbine possibly stressing the liver and kidneys at higher doses. Before starting it, please run it by your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Husain I, Manda V, Alhusban M, et al. Modulation of CYP3A4 and CYP2C9 activity by Bulbine natalensis and its constituents: An assessment of HDI risk of B. natalensis containing supplements. Phytomedicine 2021;81:153416. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 3

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

Theoretically, Bulbine natalensis stem might reduce the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that Bulbine natalensis stem extract induces CYP3A4 mRNA expression and enzyme activity. Theoretically, this may increase the metabolism of CYP3A4 substrates, but this has not been studied in humans.
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 gist for you. Your body uses an enzyme called CYP3A4 to help break down estrogen and clear it out. Lab studies suggest Bulbine natalensis may rev up that enzyme, meaning it could speed up how fast estrogen gets removed from your system. If that happens, you may end up with less estrogen working in your body, which could let symptoms creep back, things like hot flashes, night sweats, or vaginal dryness.

I want to be honest about the strength of this, though. This is only seen in test-tube research and hasn't been studied in real people, so it's theoretical. On top of that, animal studies have flagged possible liver and kidney concerns with this supplement. Please run it by your pharmacist or doctor before combining the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Husain I, Dale OR, Manda V, et al. Bulbine natalensis (currently Bulbine latifolia) and select bulbine knipholones modulate the activity of AhR, CYP1A2, CYP2B6, and P-gp. Planta Med 2022;88(12):975-984. PubMed
Moderate

P-GLYCOPROTEIN SUBSTRATES

3 of 3

Estrogen also falls under P-GLYCOPROTEIN SUBSTRATES.

Theoretically, Bulbine natalensis stem might increase the levels and clinical effects of p-glycoprotein substrates.
In vitro research shows that Bulbine natalensis stem extract induces p-glycoprotein mRNA expression; however, effects on transporter expression were not evaluated.
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 honest picture for combining Bulbine natalensis with your estrogen. Estrogen is moved around the body partly by a transporter pump called P-glycoprotein, and this supplement has only been studied in a lab dish, where it appeared to turn up the gene for that pump. That's a very early, theoretical signal, not something proven in people, so I wouldn't lose sleep over it.

If that lab finding did translate to humans, more active pumping could lower your estrogen levels a bit, which might mean your hot flashes, vaginal dryness, or other menopause symptoms aren't as well controlled. On top of that, Bulbine itself has animal data hinting at possible liver and kidney strain. Please run it past your pharmacist or doctor before starting it rather than changing anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Husain I, Manda V, Alhusban M, et al. Modulation of CYP3A4 and CYP2C9 activity by Bulbine natalensis and its constituents: An assessment of HDI risk of B. natalensis containing supplements. Phytomedicine 2021;81:153416. 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

Bulbine Natalensis Also Interacts With Other Medications

Bulbine Natalensis has 918 moderate known drug interactions in our database — the Estrogen one above is among them. If you take anything else, check it against the full list below.

Moderate 918 No known interaction 1,912 (incl. Estrogen)
Taking anything else?

Check Another of Your Medications Against Bulbine Natalensis

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

From our Q&A

Questions About Bulbine Natalensis or Estrogen

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

This page covers Bulbine Natalensis only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Estrogen page lists 211 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 Adrafinil (moderate).

By severity: 3 major · 170 moderate · 38 minor.

From our pharmacist’s overview on the Estrogen page

“If you take estrogen, this is a list to handle with real care. Of the 211 supplements and herbs with an interaction on file, three carry a major rating, and I would want you to understand those first.”

Reviewed by 2 · Jul 18, 2026

Open the Estrogen interaction page

One more smart check

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

We hold 51 real supplement products containing Bulbine Natalensis, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bulbine Natalensis. Your product may carry other ingredients that interact with Estrogen too, on top of Bulbine Natalensis — 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 Bulbine Natalensis and Estrogen 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 Bulbine Natalensis
Steady interest

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

29 days ago today
Medication Estrogen
Top 5%

#122 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 Bulbine Natalensis

What is Bulbine Natalensis?

  • Boosting testosterone
  • Improving libido
  • Muscle building and athletic performance
  • General male vitality

Bulbine natalensis is a South African plant marketed mainly as a testosterone-boosting and libido supplement, but the human evidence is essentially absent and most claims come from animal studies. Animal research has also raised concerns about possible liver and kidney harm at higher doses, so caution is warranted. Talk to your pharmacist or doctor before trying it.

Read the full Bulbine Natalensis monograph & all interactions
Medication

About Estrogen

What Is Estrogen Used For?

Brand name: Estrogen

Based on the available product information, this Estrogen product is intended for external use on the skin — specifically the face, neck, or body. It is applied as part of a daily skincare routine.

For any specific medical concerns, the label recommends consulting a healthcare provider before use.

See full Estrogen drug information
Keep checking

Other Drugs & Bulbine Natalensis

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

0Major
918Moderate
0Minor
1,911No known interaction
918 Moderate 1,911 No interaction
Moderate

918 interactions

Showing 60 of 918 moderate interactions — see all 918 on the Bulbine Natalensis page.

No interaction 1,911 drugs checked — show the list

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

Showing the 60 most looked-up of 1,911 medications checked with no known interaction — see the full Bulbine Natalensis list.

See the full Bulbine Natalensis interactions page
See every supplement checked against Estrogen, 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
Bulbine Natalensis monograph › Uses, safety, and every drug interaction in one place Estrogen supplement interactions › Every supplement checked against Estrogen, ranked by severity Estrogen 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 Bulbine Natalensis and Estrogen Together: Common Questions

Can you take Bulbine Natalensis with Estrogen?
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 3 interactions listed for Bulbine Natalensis and Estrogen?
Estrogen belongs to more than one drug category, and Bulbine Natalensis 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 Bulbine Natalensis and Estrogen 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 Estrogen and Bulbine Natalensis?

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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.