Drug & supplement interaction

Pregnenolone + Relugolix, Estradiol, Norethindrone Acetate

Relugolix, Estradiol, Norethindrone Acetate brand name: Myfembree.

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

Relugolix, Estradiol, Norethindrone Acetate falls into 2 drug categories that Pregnenolone can interact with; the most serious is rated moderate. Theoretically, taking pregnenolone might enhance the effects of estrogens.

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

Pregnenolone and Relugolix, Estradiol, Norethindrone Acetate

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

Why Are There 2 Interactions?

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

Moderate

ESTROGENS

1 of 2

Why this applies to Relugolix, Estradiol, Norethindrone Acetate

Relugolix, Estradiol, Norethindrone Acetate falls under ESTROGENS — the group Pregnenolone interacts with.

Theoretically, taking pregnenolone might enhance the effects of estrogens.
Pregnenolone is a precursor for several steroid hormones, including estrogens.
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

Myfembree already contains estradiol, which is a form of estrogen. Here's the connection: your body uses pregnenolone as a starting material to build several hormones, and estrogen is one of them. So in theory, adding a pregnenolone supplement could nudge your overall estrogen activity a little higher on top of what Myfembree provides.

I want to be honest that this is a theoretical concern based on how these hormones are made, not something proven in real people. Still, if more estrogen effect did show up, you might notice things like breast tenderness, bloating, nausea, headaches, or mood changes. Since both are hormones, it's worth a quick chat with your doctor or pharmacist before combining them rather than guessing on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Devlin TM, ed. Textbook of Biochemistry With Clinical Correlations. third ed. New York: Wiley-Liss Inc., 1992.
Moderate

PROGESTIN

2 of 2

Relugolix, Estradiol, Norethindrone Acetate also falls under PROGESTIN.

Theoretically, taking pregnenolone might enhance the effects of progestin.
Pregnenolone is a precursor for several steroid hormones, including progestin.
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 thinking on this combo. Myfembree already gives you a fixed dose of hormones, including the progestin norethindrone. Pregnenolone is a hormone your body can turn into several other steroid hormones, progestins among them. So in theory, stacking pregnenolone on top of Myfembree could add a little extra progestin-like activity. This is only a theoretical concern based on how these hormones work, not something proven in real patients.

If anything did shift, you might notice more of the usual progestin-type effects, things like breast tenderness, bloating, mood changes, or irregular spotting. Since Myfembree is a hormone product on its own, I'd loop in your doctor or pharmacist before adding pregnenolone rather than guessing.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Devlin TM, ed. Textbook of Biochemistry With Clinical Correlations. third ed. New York: Wiley-Liss Inc., 1992.

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

Pregnenolone Also Interacts With Other Medications

Pregnenolone has 81 moderate known drug interactions in our database — the Relugolix, Estradiol, Norethindrone Acetate one above is among them. If you take anything else, check it against the full list below.

Moderate 81 No known interaction 2,749 (incl. Relugolix, Estradiol, Norethindrone Acetate)
Taking anything else?

Check Another of Your Medications Against Pregnenolone

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

Everything else you take

See Every Supplement That Interacts With Relugolix, Estradiol, Norethindrone Acetate

This page covers Pregnenolone only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Relugolix, Estradiol, Norethindrone Acetate page lists 219 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 · 174 moderate · 37 minor.

From our pharmacist’s overview on the Relugolix, Estradiol, Norethindrone Acetate page

“Grapefruit is where I would start on this page. Myfembree (relugolix, estradiol, and norethindrone acetate) depends on the CYP3A4 enzyme to be cleared, and grapefruit juice blocks that enzyme, raising drug levels and side effect risk.”

Reviewed by 2 · Jul 18, 2026

Open the Relugolix, Estradiol, Norethindrone Acetate interaction page

One more smart check

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

We hold 303 real supplement products containing Pregnenolone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Pregnenolone. Your product may carry other ingredients that interact with Relugolix, Estradiol, Norethindrone Acetate too, on top of Pregnenolone — 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 Pregnenolone and Relugolix, Estradiol, Norethindrone Acetate 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 Pregnenolone
Top half

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

29 days ago today
Medication Relugolix, Estradiol, Norethindrone Acetate
Top 25%

#316 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 Pregnenolone

What is Pregnenolone?

Pregnenolone
  • Memory and cognitive support
  • Anxiety and stress
  • Anti-aging
  • Fatigue and low energy
  • Mood support

Pregnenolone is a hormone your body makes naturally and a building block for other hormones like cortisol, DHEA, estrogen, and testosterone. It is sold as a supplement for memory, mood, and anti-aging, but solid human evidence for these uses is very limited. Because it is a hormone, talk with your pharmacist or doctor before using it.

Read the full Pregnenolone monograph & all interactions
Medication

About Relugolix, Estradiol, and Norethindrone

What Is Relugolix, Estradiol, and Norethindrone Used For?

Brand name: Myfembree

Myfembree is approved for two conditions in premenopausal women: managing heavy menstrual bleeding caused by uterine fibroids (non-cancerous growths in the uterus), and managing moderate to severe pain caused by endometriosis (a condition where tissue similar to the uterine lining grows outside the uterus).

Treatment with Myfembree should not exceed 24 months because of the risk of ongoing bone loss that may not fully reverse after stopping the medication.

See full Relugolix, Estradiol, and Norethindrone drug information
Keep checking

Other Drugs & Pregnenolone

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

0Major
81Moderate
0Minor
2,748No known interaction
81 Moderate 2,748 No interaction
Moderate

81 interactions

Showing 60 of 81 moderate interactions — see all 81 on the Pregnenolone page.

No interaction 2,748 drugs checked — show the list

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

Showing the 60 most looked-up of 2,748 medications checked with no known interaction — see the full Pregnenolone list.

See the full Pregnenolone interactions page
See every supplement checked against Relugolix, Estradiol, Norethindrone Acetate, 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
Pregnenolone monograph › Uses, safety, and every drug interaction in one place Relugolix, Estradiol, Norethindrone Acetate supplement interactions › Every supplement checked against Relugolix, Estradiol, Norethindrone Acetate, ranked by severity Relugolix, Estradiol, and Norethindrone 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 Pregnenolone and Relugolix, Estradiol, Norethindrone Acetate Together: Common Questions

Can you take Pregnenolone with Relugolix, Estradiol, Norethindrone Acetate?
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 Pregnenolone and Relugolix, Estradiol, Norethindrone Acetate?
Relugolix, Estradiol, Norethindrone Acetate belongs to more than one drug category, and Pregnenolone 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 Pregnenolone and Relugolix, Estradiol, Norethindrone Acetate 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 Relugolix, Estradiol, Norethindrone Acetate and Pregnenolone?

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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.