Drug & supplement interaction

Fo-ti + Hydrochlorothiazide, Losartan Potassium

Hydrochlorothiazide, Losartan Potassium brand name: Hyzaar.

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

Hydrochlorothiazide, Losartan Potassium falls into 2 drug categories that Fo-ti can interact with; the most serious is rated moderate. Theoretically, fo-ti might increase the levels and clinical effects of drugs metabolized by CYP3A4.

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

Fo-ti and Hydrochlorothiazide, Losartan Potassium

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

Why Are There 2 Interactions?

Fo-ti interacts with whole categories of medication. Hydrochlorothiazide, Losartan Potassium falls into 2 of those categories, so it can interact with Fo-ti in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Hydrochlorothiazide, Losartan Potassium

Hydrochlorothiazide, Losartan Potassium falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Fo-ti interacts with.

Theoretically, fo-ti might increase the levels and clinical effects of drugs metabolized by CYP3A4.
In vitro research suggests that fo-ti might inhibit CYP3A4. One in vitro study suggests that the degree of CYP3A4 inhibition may depend on the type of fo-ti extract (i.e., the raw plant leads to greater inhibition than extensively processed extracts). However, this evidence conflicts with animal research suggesting that fo-ti does not inhibit CYP3A4. This interaction has not been reported 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 with Hyzaar (which combines losartan and hydrochlorothiazide). The concern on file is that Fo-ti might slow down a liver enzyme called CYP3A4, which could theoretically let certain drugs build up. For losartan specifically, it's actually a bit of a special case. Losartan is partly a prodrug, meaning your body converts some of it into a stronger active form using liver enzymes. So a blocker could, in theory, shift how much active drug you make, though the blood-pressure effect is hard to predict here.

Honestly, this is very weak, theoretical evidence from lab dishes, not from people, and it doesn't really apply to the water-pill part at all. I wouldn't lose sleep over it. Still, given Fo-ti's separate liver concerns, run it by your pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
  2. Zhang Y, Ding T, Diao T, Deng M, Chen S. Effects of Polygonum multiflorum on the activity of cytochrome P450 isoforms in rats. Pharmazie 2015;70(1):47-54. DOI
  3. Xing Y, Yu Q, Zhou L, et al. Cytochrome P450-mediated herb-drug interaction (HDI) of Polygonum multiflorum Thunb. based on pharmacokinetic studies and in vitro inhibition assays. Phytomedicine 2023;112:154710. PubMed
Moderate

DIURETIC DRUGS

2 of 2

Hydrochlorothiazide, Losartan Potassium also falls under DIURETIC DRUGS.

Theoretically, fo-ti, particularly raw fo-ti root, might increase the risk of hypokalemia when taken with diuretic drugs.
Raw fo-ti root contains anthraquinone derivatives, which might have stimulant laxative effects and compound diuretic-induced potassium loss. In vitro research shows that fermented and processed fo-ti root have reduced laxative effects compared with raw fo-ti root.
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

Hyzaar combines two blood pressure medicines: hydrochlorothiazide (a water pill) and losartan. The water pill side already nudges your body to lose some potassium through your urine. Here is where Fo-ti comes in. Raw Fo-ti root contains anthraquinones, plant compounds that can act like a stimulant laxative. If those two effects stack, you could lose more potassium than usual.

This is a theory based on how these things work, not something proven in studies, so I would not panic. Still, watch for signs of low potassium like muscle cramps, weakness, or an irregular heartbeat. Processed or fermented Fo-ti has a weaker laxative effect than the raw root. Before adding Fo-ti, please check with your pharmacist or doctor, especially since Fo-ti has also been tied to liver concerns.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
  2. Laird AR, Ramchandani N, deGoma EM, et al. Acute hepatitis associated with the use of an herbal supplement (Polygonum multiflorum) mimicking iron-overload syndrome. J Clin Gastroenterol 2008;42:861-2. PubMed
  3. Yu J, Xie J, Mao XJ, et al. Comparison of laxative and antioxidant activities of raw, processed and fermented Polygoni multiflori radix. Chin J Nat Med 2012;10(1):63-7. DOI

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

Fo-ti Also Interacts With Other Medications

Fo-ti has 1,256 moderate known drug interactions in our database — the Hydrochlorothiazide, Losartan Potassium one above is among them. If you take anything else, check it against the full list below.

Moderate 1,256 No known interaction 1,574 (incl. Hydrochlorothiazide, Losartan Potassium)
Taking anything else?

Check Another of Your Medications Against Fo-ti

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

Everything else you take

See Every Supplement That Interacts With Hydrochlorothiazide, Losartan Potassium

This page covers Fo-ti only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydrochlorothiazide, Losartan Potassium page lists 314 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 12 major · 259 moderate · 43 minor.

From our pharmacist’s overview on the Hydrochlorothiazide, Losartan Potassium page

“Grapefruit is the everyday item to know first if you take hydrochlorothiazide with losartan (Hyzaar). It blocks the enzyme that clears losartan, raising drug levels, and it is one of 12 major-rated entries on a list of 314 supplements and herbs, enough serious risk to warrant genuine care.”

Reviewed by 2 · Jul 18, 2026

Open the Hydrochlorothiazide, Losartan Potassium interaction page

One more smart check

Taking Fo-ti as Part of a Dietary Supplement Product? Check It for Interactions

We hold 976 real supplement products containing Fo-ti, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Fo-ti. Your product may carry other ingredients that interact with Hydrochlorothiazide, Losartan Potassium too, on top of Fo-ti — 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 Fo-ti and Hydrochlorothiazide, Losartan Potassium 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 Fo-ti
Top 25%

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

29 days ago today
Medication Hydrochlorothiazide, Losartan Potassium
Top 25%

#640 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 Fo-ti

What is Fo-ti?

  • Anti-aging and longevity
  • Hair graying and hair loss
  • General tonic for vitality
  • Constipation
  • High cholesterol

Fo-ti (He Shou Wu) is a root used in traditional Chinese medicine, often promoted for healthy aging and hair. High-quality human evidence for these benefits is limited, and processed Fo-ti has been linked to reports of liver injury, so caution and professional guidance are important.

Read the full Fo-ti monograph & all interactions
Keep checking

Other Drugs & Fo-ti

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

0Major
1,256Moderate
0Minor
1,573No known interaction
1,256 Moderate 1,573 No interaction
Moderate

1,256 interactions

Showing 60 of 1,256 moderate interactions — see all 1,256 on the Fo-ti page.

No interaction 1,573 drugs checked — show the list

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

Showing the 60 most looked-up of 1,573 medications checked with no known interaction — see the full Fo-ti list.

See the full Fo-ti interactions page
See every supplement checked against Hydrochlorothiazide, Losartan Potassium, 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
Fo-ti monograph › Uses, safety, and every drug interaction in one place Hydrochlorothiazide, Losartan Potassium supplement interactions › Every supplement checked against Hydrochlorothiazide, Losartan Potassium, 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 Fo-ti and Hydrochlorothiazide, Losartan Potassium Together: Common Questions

Can you take Fo-ti with Hydrochlorothiazide, Losartan Potassium?
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 Fo-ti and Hydrochlorothiazide, Losartan Potassium?
Hydrochlorothiazide, Losartan Potassium belongs to more than one drug category, and Fo-ti 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 Fo-ti and Hydrochlorothiazide, Losartan Potassium 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

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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.