Bulbine Natalensis + Ethinyl estradiol, Levonogestrel
Ethinyl estradiol, Levonogestrel brand name: Lybrel.
Ethinyl estradiol, Levonogestrel 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 reportBulbine Natalensis and Ethinyl estradiol, Levonogestrel
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. Ethinyl estradiol, Levonogestrel 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).
CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES
1 of 3Why this applies to Ethinyl estradiol, Levonogestrel
Ethinyl estradiol, Levonogestrel falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Bulbine Natalensis interacts with.
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.
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.
Here's the quick version for your birth control pill (Lybrel, which is ethinyl estradiol plus levonorgestrel). In lab dishes, Bulbine natalensis seemed to slightly speed up an enzyme called CYP1A2, one of the helpers your body uses to break down estrogen. If that happened in real people, your body might clear the hormones a little faster, which could in theory lower the protection and lead to breakthrough bleeding or spotting, or even a higher chance of an unplanned pregnancy.
That said, this is only a theory from test-tube research, never confirmed in humans, so I wouldn't lose sleep over it. Because your pill works best at steady levels, I'd still mention this combo to your pharmacist or doctor before starting Bulbine, especially since this supplement also raises liver and kidney concerns.
- 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
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
2 of 3Ethinyl estradiol, Levonogestrel also falls under CYTOCHROME P450 3A4 (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.
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.
Here's the concern with pairing Lybrel (a birth control pill containing ethinyl estradiol and levonorgestrel) with Bulbine natalensis. Your body clears these hormones partly through a liver enzyme called CYP3A4. Lab studies suggest Bulbine may rev that enzyme up (induce it), which could mean your body breaks down the hormones faster and keeps less of them around.
For a birth control pill, lower hormone levels can mean weaker protection against pregnancy and more breakthrough bleeding or spotting. I want to be honest, though: this is only a theoretical worry based on test-tube research, with nothing proven in people. Because an unplanned pregnancy is a big deal, I'd still talk with your pharmacist or doctor before combining them, and ask about a backup method just in case.
- 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
P-GLYCOPROTEIN SUBSTRATES
3 of 3Ethinyl estradiol, Levonogestrel also falls under 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.
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.
Here's the short version on combining Bulbine natalensis with your birth control pill (Lybrel, which contains ethinyl estradiol and levonorgestrel). This plant is moved partly by a protein pump in your gut and liver called P-glycoprotein. In lab dishes, Bulbine appeared to rev up that pump, which could push more of your hormones out before they're absorbed. In theory, that might leave you with slightly lower hormone levels.
Why this matters: with a birth control pill, even small drops in hormone levels can mean less reliable protection or some breakthrough spotting. I want to stress this is only a theoretical, test-tube finding, not proven in people. Still, since pregnancy prevention is at stake, please check with your pharmacist or doctor before pairing them.
- 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.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Bulbine Natalensis Also Interacts With Other Medications
Bulbine Natalensis has 918 moderate known drug interactions in our database — the Ethinyl estradiol, Levonogestrel one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Bulbine Natalensis
We haven’t checked that one against Bulbine Natalensis yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Bulbine Natalensis. Pick one to open its full report.
See Every Supplement That Interacts With Ethinyl estradiol, Levonogestrel
This page covers Bulbine Natalensis only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethinyl estradiol, Levonogestrel page lists 239 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).
By severity: 6 major · 195 moderate · 38 minor.
From our pharmacist’s overview on the Ethinyl estradiol, Levonogestrel page
“A daily birth control pill like Lybrel (ethinyl estradiol with levonorgestrel) only works when enough hormone stays in the bloodstream, and that is exactly what several supplements on this page can undermine. This list deserves genuine care, starting with the six major-rated entries.”
Reviewed by 2 · Jul 18, 2026
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 Ethinyl estradiol, Levonogestrel 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:
Where Bulbine Natalensis and Ethinyl estradiol, Levonogestrel 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.
#568 of 1,452 supplements looked up here in the last 7 days
#526 of 2,830 medications looked up here in the last 7 days
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.
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.
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.
No drugs match “”.
918 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Theophylline ›
- Nifedipine ›
- Ibuprofen ›
- Aspirin ›
- Hydrocortisone ›
- Naproxen ›
- Doxycycline ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Tetracycline ›
- Lidocaine ›
- Ranitidine ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Glyburide ›
- Methyltestosterone ›
- Triazolam ›
- Zopiclone ›
- Colchicine ›
- Fentanyl ›
- Flurbiprofen ›
- Oxybutynin ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Triamcinolone ›
- Apomorphine ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Dipyridamole ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Indomethacin ›
- Miconazole ›
- Morphine Sulfate ›
- Trimipramine ›
- Acetaminophen ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Everolimus ›
- Ivabradine ›
- Ivermectin ›
- Ketoprofen ›
- Lofepramine ›
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.
- Levothyroxine ›
- Methylphenidate ›
- Metoprolol ›
- Rosuvastatin ›
- Escitalopram ›
- Docusate ›
- Tirzepatide ›
- Hydroxyurea ›
- Methamphetamine ›
- Valacyclovir ›
- Semaglutide ›
- Sumatriptan ›
- Lisdexamfetamine ›
- Metformin ›
- Lisinopril ›
- Amoxicillin ›
- Isotretinoin ›
- Methotrexate ›
- Bupropion ›
- Amphetamine ›
- Acyclovir ›
- Azithromycin ›
- Lamotrigine ›
- Pregabalin ›
- Gabapentin ›
- Dextroamphetamine ›
- Methylene Blue ›
- Duloxetine ›
- Levothyroxine, Liothyronine ›
- Ciprofloxacin ›
- Bisoprolol ›
- Candesartan Cilexetil ›
- Amoxicillin, Clavulanate Potassium ›
- Acetaminophen, Dextromethorphan, Doxylamine ›
- Cyclopentolate ›
- Cephalexin ›
- Mannitol ›
- Roxithromycin ›
- Levetiracetam ›
- Ezetimibe ›
- Phentermine, Topiramate ›
- Dexmethylphenidate ›
- Levothyroxine Sodium ›
- Carbidopa, Levodopa ›
- Thyroid Hormone ›
- Spironolactone ›
- Pizotifen ›
- Daptomycin ›
- Venlafaxine ›
- Pegunigalsidase Alfa-iwxj ›
- Mitomycin ›
- Levodopa ›
- Hexobarbitone ›
- Flutemetamol F-18 ›
- Magnesium Hydroxide (otc Drug) ›
- Bentoquatam ›
- Insulin Degludec, Liraglutide ›
- Canagliflozin, Metformin ›
- Cefaclor ›
- Factor 7a ›
Showing the 60 most looked-up of 1,911 medications checked with no known interaction — see the full Bulbine Natalensis list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Ethinyl estradiol, Levonogestrel Is Linked to Lower Levels of 7 Nutrients
Natural Medicines records Ethinyl estradiol, Levonogestrel as a medicine that can lower these. This is not an interaction with Bulbine Natalensis — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Read the full Ethinyl estradiol, Levonogestrel nutrient depletion report ›
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Bulbine Natalensis and Ethinyl estradiol, Levonogestrel Together: Common Questions
Can you take Bulbine Natalensis with Ethinyl estradiol, Levonogestrel?
Why are there 3 interactions listed for Bulbine Natalensis and Ethinyl estradiol, Levonogestrel?
How serious is the Bulbine Natalensis and Ethinyl estradiol, Levonogestrel interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Still Have a Question About Ethinyl estradiol, Levonogestrel and Bulbine Natalensis?
Our pharmacists answer your medication & supplement questions — free.
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.