Fisetin Drug Interactions: What to Watch For (2026)

What is known about fisetin drug interactions?

There are insufficient controlled human studies to define fisetin's interactions with prescription medicines. Current concerns largely come from preclinical enzyme experiments, known properties of individual medicines and the exclusion criteria used by clinical trials. Those observations can identify reasons for caution but cannot quantify actual interaction risk.

People taking anticoagulants, antiplatelet agents, oncology drugs, immunosuppressants or medicines with narrow therapeutic ranges should seek individual prescriber or pharmacist advice before starting fisetin. For the wider evidence, see our side effects and safety review.

Drug interactions: level of evidence by medication class

Medicine or pathway	Current evidence	What this means
CYP2C8 substrates, including certain anticancer drugs	Fisetin and geraldol reversibly inhibited CYP2C8 in pooled human liver microsomes, with Ki values of 4.1 and 11.5 µM, respectively [7].	A mechanistic interaction is possible; magnitude after oral supplements has not been tested in people. Oncology teams should review all supplements.
Warfarin and direct oral anticoagulants	Clinical coadministration effects and bleeding event rates for fisetin are not established.	Medication review is important; do not change prescribed anticoagulation or use in-vitro assays as a clinical risk estimate.
Aspirin and other antiplatelet agents	Laboratory platelet-pathway observations do not quantify bleeding risk from combining fisetin with these drugs.	Check for other supplements and bleeding risks with a clinician or pharmacist.
Chemotherapy, tyrosine kinase inhibitors and immunosuppressants	Potential enzyme, transporter or immune effects remain formulation- and drug-specific; controlled clinical fisetin interaction studies are lacking.	Review with the treating specialist before combining high supplemental doses.
Statins, antidepressants and diabetes medicines	Insufficient direct human fisetin interaction evidence; effects cannot be assumed absent or clinically important.	Do not stop medication; individualized review is warranted when introducing high-dose supplements.

Important: a microsome experiment is not a human drug-interaction trial. The table identifies evidence gaps and reasons to check medicines; it is not a list of proven contraindications. See also fisetin safety and pregnancy and breastfeeding.

What does fisetin do to drug-metabolising enzymes?

Laboratory studies suggest that fisetin and its metabolites may interact with drug-metabolising enzymes, but the size and clinical relevance of these effects have not been established by controlled human drug-interaction trials [2]. A small human pharmacokinetic study measured circulating parent fisetin after a single oral dose, not concentrations at all relevant tissues or the effects of combining fisetin with medicines [3].

Low parent-fisetin plasma concentrations do not prove that medication interactions are negligible: intestinal exposure, active metabolites, repeated dosing and absorption-enhanced formulations may differ. The safest interpretation is uncertainty rather than reassurance.

Which medications need particular caution?

Warfarin and direct oral anticoagulants (DOACs)

Flavonoids as a class are sometimes described as having mild antiplatelet activity, but this hasn't been well established for natural dietary flavonoids under real physiological conditions, and it hasn't been tested for fisetin specifically. Whether it's clinically meaningful at typical fisetin supplement doses in a patient already on warfarin, apixaban, rivaroxaban, dabigatran, or edoxaban is unknown. That uncertainty is exactly why the theoretical concern is worth naming: the consequences of an added bleeding risk going unnoticed are serious even if the underlying mechanism turns out to be weak. Anyone on an anticoagulant should discuss fisetin with their prescriber before starting, and INR (for warfarin) should be monitored more closely in the first month after starting.

Antiplatelet drugs (aspirin, clopidogrel, ticagrelor)

An additional antiplatelet effect from concentrated fisetin is theoretical and inadequately studied in humans. Do not assume that low-dose aspirin or another antiplatelet medicine is unaffected. Speak with the treating clinician before adding fisetin, especially if taking two antiplatelet medicines or also using an anticoagulant.

Tyrosine kinase inhibitors

Fisetin's clinical trials have explicitly excluded participants on tyrosine kinase inhibitors [5] [6]. The reasoning is mechanistic: fisetin's senolytic action involves inhibiting some of the same survival pathways that pharmaceutical tyrosine kinase inhibitors target, so additive or antagonistic effects are theoretically possible. If you're on imatinib, dasatinib, nilotinib, sunitinib, or another TKI, don't take fisetin without oncology guidance.

CYP2C8 substrates

Because fisetin is a CYP2C8 substrate and mild inhibitor, it may interact with other drugs cleared this way. The clinically important CYP2C8 substrates include repaglinide (a diabetes drug), montelukast (an asthma medication), amiodarone (an antiarrhythmic), amodiaquine and chloroquine (antimalarials), and rosiglitazone. If you're on any of these, discuss fisetin with your prescriber.

Statins

There is no controlled human study demonstrating whether fisetin changes statin exposure or adverse effects. Because metabolism and transport differ between individual statins, a pharmacist or prescriber should review the specific medicine and fisetin product rather than relying on a blanket statement that ordinary fisetin doses cannot interact.

Diabetes medications

Laboratory findings raise hypotheses about glucose regulation, but human studies have not established the interaction risk of combining fisetin with insulin, sulfonylureas, repaglinide or metformin. People taking glucose-lowering medication should discuss any new high-dose supplement with their clinician and follow an individual monitoring plan rather than assuming compatibility.

Chemotherapy and targeted anti-cancer therapy

This is the category that deserves the most caution. Fisetin has documented preclinical anti-cancer activity against many cell lines, and some preclinical work has explored it as a chemosensitiser — meaning it may amplify the effects of concurrent chemotherapy [1]. Whether that's helpful or harmful depends on the specific regimen and cancer type, and it hasn't been established in any human protocol. If you have active cancer, don't take fisetin without explicit oncology guidance.

Immunosuppressants

Tacrolimus, ciclosporin, and mTOR inhibitors such as sirolimus and everolimus are CYP3A4-metabolised. Interactions with fisetin haven't been characterised. If you're on immunosuppression — after a transplant or for autoimmune therapy — don't start fisetin without guidance from your transplant or rheumatology team.

Antidepressants

Controlled human fisetin-interaction studies have not established compatibility with SSRIs, SNRIs or monoamine oxidase inhibitors. The fact that a particular medicine uses a different major metabolic pathway cannot exclude pharmacodynamic or other interactions. Ask a prescriber or pharmacist to review the actual combination.

What about combining fisetin with other supplements?

Combining ingredients because their laboratory mechanisms appear complementary does not establish safety, additive benefit or an interaction-free regimen. Human data on concentrated fisetin stacks are insufficient.

Fisetin plus quercetin

These flavonols share some preclinical actions, but the consequences of combined high-dose supplementation have not been adequately tested in humans. See our fisetin vs quercetin review.

Fisetin plus curcumin or piperine

Neither combination has a validated human safety or absorption advantage. Concentrated piperine can interact with certain medicines, so do not use it simply to increase fisetin exposure.

Fisetin plus resveratrol, spermidine, NMN or urolithin A

Different mechanisms do not prove compatibility. No adequate human interaction trials establish an optimal combined dose, timing or added clinical benefit. See our resveratrol comparison and the individual supplement comparisons for their separate evidence bases.

Do food and drink interact with fisetin?

Human studies have not established whether dietary fat, coffee, tea, grapefruit or alcohol changes fisetin exposure or clinical effects. Grapefruit and concentrated piperine can independently affect the disposition of certain prescription medicines. Check your medicines' own food-interaction instructions and seek individual advice rather than treating the absence of a fisetin-specific study as evidence of safety.

Further reading: the separate evidence on blood-pressure effects; the practical timing and supplement-use guide. There is no validated universal medication hold period for fisetin.

What we still don't know

Whether any of the theoretical CYP-mediated interactions produce measurable clinical effects at typical fisetin supplement doses in humans is unknown — no human drug-drug interaction study exists.

Whether bioavailability-enhanced fisetin formulations, such as liposomal or hydrogel versions, meaningfully change the interaction profile is untested — higher plasma levels raise the theoretical interaction potential.

Whether specific groups — older adults, or people who metabolise CYP2C8 poorly — face elevated interaction risk hasn't been studied.

How fisetin interacts with common polypharmacy patterns, such as a statin plus an ACE inhibitor plus aspirin plus a proton pump inhibitor, hasn't been characterised.

Whether interactions differ between pulsed and continuous dosing regimens is unknown. Pulsed dosing produces higher, briefer plasma peaks; continuous dosing produces lower, sustained levels. The interaction profiles could plausibly differ.

Bottom line

Fisetin's clinical interaction profile remains uncertain. Anticoagulants, antiplatelet medicines, cancer treatments, transplant medicines and other interaction-sensitive therapies warrant particular caution. Neither low parent-fisetin plasma exposure nor the absence of published interaction cases establishes safety. Have your prescriber or pharmacist review the actual supplement, formulation, dose and medication list before use; do not discontinue or alter prescribed medicines on your own. For context, see our safety review and clinician's guide.