Drug & supplement interaction

Equol + Lactic Acid, Citric Acid, Potassium Bitartrate

Lactic Acid, Citric Acid, Potassium Bitartrate brand name: Phexxi.

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

Equol has a moderate interaction with Lactic Acid, Citric Acid, Potassium Bitartrate. Theoretically, equol might increase the levels and clinical effects of ethinyl estradiol found in contraceptive drugs.

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

Equol and Lactic Acid, Citric Acid, Potassium Bitartrate

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

Moderate

CONTRACEPTIVE DRUGS

Why this applies to Lactic Acid, Citric Acid, Potassium Bitartrate

Lactic Acid, Citric Acid, Potassium Bitartrate falls under CONTRACEPTIVE DRUGS — the group Equol interacts with.

Theoretically, equol might increase the levels and clinical effects of ethinyl estradiol found in contraceptive drugs.
In vitro research shows that equol inhibits the binding of estradiol to serum proteins. Theoretically, this might increase the concentration of free, bioactive estradiol, thereby increasing the risk of adverse effects from ethinyl estradiol, including headaches, breast tenderness, dysmenorrhea, and weight gain.
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 good news: this interaction on file is really about estrogen-based birth control like the pill, where equol could theoretically nudge up the amount of active estrogen floating around. But Phexxi (lactic acid, citric acid, and potassium bitartrate) works in a completely different way. It's a non-hormonal gel you place in the vagina right before sex, and it simply lowers the pH so sperm can't swim well. There's no estrogen for equol to interact with.

So this particular concern really doesn't apply to Phexxi. The note is based only on lab data and on hormonal contraceptives, not on this product. That said, if you're combining supplements with any birth control, it never hurts to run it by your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Martin ME, Haouriqui M, Pelissero C, et al. Interactions between phytoestrogens and human sex steroid binding protein. Life Sci 1996;58:429-36. 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

Equol Also Interacts With Other Medications

Equol has 57 moderate, 75 minor known drug interactions in our database — the Lactic Acid, Citric Acid, Potassium Bitartrate one above is one of them. If you take anything else, check it against the full list below.

Moderate 57 Minor 75 No known interaction 2,698 (incl. Lactic Acid, Citric Acid, Potassium Bitartrate)
Taking anything else?

Check Another of Your Medications Against Equol

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

Everything else you take

See Every Supplement That Interacts With Lactic Acid, Citric Acid, Potassium Bitartrate

This page covers Equol only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lactic Acid, Citric Acid, Potassium Bitartrate page lists 33 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: St. John's Wort (major), Activated Charcoal (moderate), Alfalfa (moderate), Anise (moderate) and Black Tea (moderate).

By severity: 1 major · 21 moderate · 11 minor.

From our pharmacist’s overview on the Lactic Acid, Citric Acid, Potassium Bitartrate page

“St. John's wort is the entry I would not brush past.”

Reviewed by 2 · Jul 18, 2026

Open the Lactic Acid, Citric Acid, Potassium Bitartrate interaction page

How much people look this up

Where Equol and Lactic Acid, Citric Acid, Potassium Bitartrate 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 Equol
Top half

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

29 days ago today
Medication Lactic Acid, Citric Acid, Potassium Bitartrate
Top half

#1,191 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 Equol

What is Equol?

  • Menopause symptoms (hot flashes)
  • Bone health support
  • Skin aging
  • Prostate health
  • General hormone balance

Equol is a compound made in the gut when some people break down soy isoflavones, and it is also sold as a supplement. Early research links it to possible benefits for menopause symptoms and bone or skin health, but the evidence is still limited and far from proven. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Equol monograph & all interactions
Medication

About Lactic Acid, Citric Acid, and Potassium Bitartrate Vaginal Contraceptive

What Is Lactic Acid, Citric Acid, and Potassium Bitartrate Vaginal Contraceptive Used For?

Brand name: Phexxi

PHEXXI is used to prevent pregnancy in people who can become pregnant. It's an on-demand contraceptive, meaning you use it only when you need it — right before vaginal sex.

Important to know: PHEXXI does not work if you use it after intercourse. It must be applied beforehand to be effective.

See full Lactic Acid, Citric Acid, and Potassium Bitartrate Vaginal Contraceptive drug information Lactic Acid, L-, Citric Acid Monohydrate, And Potassium Bitartrate NDC codes and packages
Keep checking

Other Drugs & Equol

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

0Major
57Moderate
75Minor
2,697No known interaction
57 Moderate 75 Minor 2,697 No interaction
Moderate

57 interactions

Minor

75 interactions

Showing 60 of 75 minor interactions — see all 75 on the Equol page.

No interaction 2,697 drugs checked — show the list

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

Showing the 60 most looked-up of 2,697 medications checked with no known interaction — see the full Equol list.

See the full Equol interactions page
See every supplement checked against Lactic Acid, Citric Acid, Potassium Bitartrate, 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
Equol monograph › Uses, safety, and every drug interaction in one place Lactic Acid, Citric Acid, Potassium Bitartrate supplement interactions › Every supplement checked against Lactic Acid, Citric Acid, Potassium Bitartrate, ranked by severity Lactic Acid, Citric Acid, and Potassium Bitartrate Vaginal Contraceptive drug information › The full plain-English guide to this medication Lactic Acid, L-, Citric Acid Monohydrate, And Potassium Bitartrate NDC codes and packages › Every package, labeler and price in the FDA directory 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 Equol and Lactic Acid, Citric Acid, Potassium Bitartrate Together: Common Questions

Can you take Equol with Lactic Acid, Citric Acid, Potassium Bitartrate?
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 Equol and Lactic Acid, Citric Acid, Potassium Bitartrate 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 Lactic Acid, Citric Acid, Potassium Bitartrate and Equol?

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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.