Drug & supplement interaction

7-methoxyflavone + Letrozole, Ribociclib Succinate

Letrozole, Ribociclib Succinate brand name: Kisqali Femara Co-Pack.

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

7-methoxyflavone has a moderate interaction with Letrozole, Ribociclib Succinate. In vitro evidence shows that 7-methoxyflavone inhibits aromatase.

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

7-methoxyflavone and Letrozole, Ribociclib Succinate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

AROMATASE INHIBITORS

Why this applies to Letrozole, Ribociclib Succinate

Letrozole, Ribociclib Succinate falls under AROMATASE INHIBITORS — the group 7-methoxyflavone interacts with.

In vitro evidence shows that 7-methoxyflavone inhibits aromatase. Theoretically, 7-methoxyflavone might have an additive effects when used with other aromatase inhibitors, potentially increasing the therapeutic effects and adverse effects associated with these drugs. Some aromatase inhibitors include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara).
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

This combination pill pairs letrozole, which already blocks the aromatase enzyme to lower estrogen in breast cancer treatment, with ribociclib. Here's the thing: 7-methoxyflavone is sold as a testosterone booster because, in test-tube studies, it seems to block that same aromatase enzyme. So the worry is that you'd be doubling up on aromatase blocking. In theory, that could push estrogen even lower and add to letrozole's typical side effects, things like hot flashes, joint and bone aches, fatigue, and over time, weaker bones.

I want to be honest: this is a theoretical concern based only on lab data, not real human cases. Still, with a cancer therapy this important, I'd skip the supplement and not risk muddying your treatment. Please run it by your oncology team or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ta N, Walle T. Aromatase inhibition by bioavailable flavones. J Steroid Biochem Mol Biol 2007;107(1-2):127-9.

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

7-methoxyflavone Also Interacts With Other Medications

7-methoxyflavone has 11 moderate known drug interactions in our database — the Letrozole, Ribociclib Succinate one above is one of them. If you take anything else, check it against the full list below.

Moderate 11 No known interaction 2,819 (incl. Letrozole, Ribociclib Succinate)
Taking anything else?

Check Another of Your Medications Against 7-methoxyflavone

Covers the 2,830 medications we’ve checked against 7-methoxyflavone. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Letrozole, Ribociclib Succinate

This page covers 7-methoxyflavone only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Letrozole, Ribociclib Succinate page lists 155 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 8 major · 109 moderate · 38 minor.

From our pharmacist’s overview on the Letrozole, Ribociclib Succinate page

“Grapefruit tops my worry list for anyone taking the Kisqali Femara Co-Pack (letrozole and ribociclib), because it blocks the enzyme, CYP3A4, that clears ribociclib and can push levels of this breast cancer drug higher than intended. That enzyme thread runs through 121 of the 155 ingredients on this page, and with eight rated major, rea…”

Reviewed by 2 · Jul 18, 2026

Open the Letrozole, Ribociclib Succinate interaction page

One more smart check

Taking 7-methoxyflavone as Part of a Dietary Supplement Product? Check It for Interactions

We hold 20 real supplement products containing 7-methoxyflavone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides 7-methoxyflavone. Your product may carry other ingredients that interact with Letrozole, Ribociclib Succinate too, on top of 7-methoxyflavone — 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 7-methoxyflavone and Letrozole, Ribociclib Succinate 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 7-methoxyflavone
Top half

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

29 days ago today
Medication Letrozole, Ribociclib Succinate
Top half

#1,003 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 7-methoxyflavone

What is 7-methoxyflavone?

  • Boosting testosterone
  • Reducing estrogen (aromatase inhibition)
  • Athletic and bodybuilding performance
  • Muscle building support

7-Methoxyflavone is a lab-made or plant-derived flavonoid marketed mainly in testosterone-boosting and bodybuilding supplements based on the idea that it blocks the aromatase enzyme. However, solid human evidence that it raises testosterone, improves performance, or builds muscle is essentially lacking, and its long-term safety has not been well studied. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full 7-methoxyflavone monograph & all interactions
Keep checking

Other Drugs & 7-methoxyflavone

Browse every other medication we’ve checked against 7-methoxyflavone — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
11Moderate
0Minor
2,818No known interaction
11 Moderate 2,818 No interaction
Moderate

11 interactions

No interaction 2,818 drugs checked — show the list

We also checked 7-methoxyflavone against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,818 medications checked with no known interaction — see the full 7-methoxyflavone list.

See the full 7-methoxyflavone interactions page
See every supplement checked against Letrozole, Ribociclib Succinate, 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
7-methoxyflavone monograph › Uses, safety, and every drug interaction in one place Letrozole, Ribociclib Succinate supplement interactions › Every supplement checked against Letrozole, Ribociclib Succinate, 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 7-methoxyflavone and Letrozole, Ribociclib Succinate Together: Common Questions

Can you take 7-methoxyflavone with Letrozole, Ribociclib Succinate?
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.
How serious is the 7-methoxyflavone and Letrozole, Ribociclib Succinate 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 Letrozole, Ribociclib Succinate and 7-methoxyflavone?

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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.