Fisetin Pulse Dosing: What Human Trials Actually Use

There is no single universal fisetin pulse-dosing protocol in humans. The widely repeated “Mayo Clinic protocol” — often described online as 20 mg/kg/day for two days, then 28 days off — captures only one branch of the clinical-trial landscape.

Human fisetin studies now use one-day, two-day and three-day pulses. Some repeat treatment after one week, some after two weeks, some after 28 days, and some use only one course. Other aging studies are testing much lower intermittent doses or continuous daily dosing instead. ^[2]

The most accurate 2026 interpretation is not “What is the fisetin protocol?” but “Which fisetin protocol, for which population, and what question is that schedule designed to test?”

This matters because a trial schedule is not automatically a consumer protocol. The duration, interval, medication restrictions, formulation and clinical population are part of the intervention. Copying only the milligram number strips away most of the context.

For the full dose landscape, see our fisetin dosage review. For whether fisetin has actually demonstrated senolysis in humans, see our fisetin senolytic evidence review.

Use the right page for your question: this article compares intermittent clinical-study schedules. For dose amounts and their study populations, use the dosage guide; for administration with food, timing or splitting, read how to take fisetin; and for the limits of interpreting human plasma concentrations, see the absorption data. None of these converts research pulses into a clinically established anti-ageing protocol.

What does “pulse dosing” mean?

Pulse dosing means giving fisetin during a short treatment window, followed by a longer period with no fisetin. In senolytic research, the rationale is often described as a hit-and-run strategy: if a brief exposure eliminates a susceptible senescent-cell population, continuous drug exposure might not be necessary.

That concept has a plausible preclinical basis. Fisetin showed senotherapeutic and senolytic activity in experimental systems and mouse studies, helping drive its translation into intermittent human trials. ^[1]

But two distinctions are essential. First, intermittent dosing as a concept is not the same thing as one specific interval such as “two days every month.” Second, a plausible hit-and-run model does not establish that a particular human dose clears senescent cells systemically.

Is there really one “Mayo Clinic fisetin protocol”?

No. Several Mayo Clinic–linked studies use fisetin around 20 mg/kg/day, but their schedules are not identical.

For example, AFFIRM in older women uses 20 mg/kg/day for two consecutive days and repeats the course after one month. ^[3]

The skeletal-health trial used approximately 20 mg/kg/day for three consecutive days, repeated every 28 days over 20 weeks for five dosing periods. ^[4]

COVID-FIS used approximately 20 mg/kg/day on days 0, 1, 8 and 9 — two short courses separated by only one week, not one month. ^[5]

COVFIS-HOME also used short intermittent courses in a COVID-19 population rather than a simple once-monthly longevity schedule. ^[6]

So “Mayo Clinic protocol” is useful as a search phrase, but it should not be treated as the name of one validated regimen.

What pulse schedules have human fisetin trials actually used?

Study	Fisetin schedule	Repeat interval	Main purpose
AFFIRM	20 mg/kg/day × 2 consecutive days	Repeated after about 1 month	Frailty, inflammation and senescence-related measures in older women
Skeletal-health trial	~20 mg/kg/day × 3 consecutive days	Every 28 days; 5 dosing periods	Bone turnover and cellular-senescence targeting
COVID-FIS	~20 mg/kg/day on days 0, 1, 8 and 9	Second 2-day course after 1 week	COVID-19 severity, inflammation, frailty and senescence-related outcomes
Knee osteoarthritis trial	~20 mg/kg/day × 2 days	28 days off between 3 dosing cycles	Pain, function, cartilage and inflammatory outcomes
Fisetin HIGH	20 mg/kg/day × 2 consecutive days	Single short course	Pharmacokinetics, safety and senescence/senolysis biomarkers
STOP-Sepsis	20 mg/kg once or 20 mg/kg on 2 consecutive days	No monthly cycle; direct one-dose vs two-dose comparison	Dose strategy, organ dysfunction, senescent immune cells and safety
TROFFi	20 mg/kg/day on days 1–3	Every 14 days for 4 cycles	Physical function after breast-cancer chemotherapy
Vascular-aging trial	2 mg/kg/day × 3 days	Second 3-day course after 2 weeks	Endothelial function, arterial stiffness and senescence-related biology
FIRST / peripheral artery disease	~20 mg/kg/day × 2 days	Every 14 days	Mobility plus blood/tissue senescence-related outcomes
REVITALiSE / sarcopenia	800–2,000 mg/day by body weight × 3 days	Every 2 weeks for 12 weeks	Walk speed, grip strength, physical activity and muscle biology
ELDERDIET	20 mg/kg/day × 2 days	Monthly for at least 2 years	Combined diet, fasting and fisetin program; cannot isolate fisetin alone
SEN-SURVIVORS	20 mg/kg/day on days 1, 2, 30 and 31	Second 2-day course after about 1 month	Frailty and senescence outcomes in adult childhood-cancer survivors
CVID/GLILD pilot (2026 meeting abstract) [20]	20 mg/kg/day on days 0–1 and 28–29	Second 2-day course after 4 weeks; 180-day follow-up	Preliminary n=10 rare-lung-disease pilot; related registry lists planned n=20 and no final results

The table shows why the phrase “the fisetin pulse protocol” is misleading. Even when researchers use the same nominal 20 mg/kg/day dose, they vary the number of consecutive days and the interval between courses. ^[2]

Why did 20 mg/kg become such a common research dose?

Approximately 20 mg/kg/day became common because early translational fisetin programs were built from preclinical senolytic work and then moved into small human studies using short, relatively high exposures. ^[1]

That historical pathway explains why the number appears repeatedly. It does not establish that 20 mg/kg is the optimal human senolytic dose.

The current trial landscape itself demonstrates that investigators are still testing that assumption. Fisetin HIGH is studying 20 mg/kg/day for two days specifically to characterize pharmacokinetics, safety, tolerability and candidate senescence/senolysis biomarkers rather than treating the regimen as a settled therapeutic standard. ^[8]

For a 70 kg participant, 20 mg/kg corresponds to 1,400 mg per treatment day. That arithmetic is useful for reading trials, but it should not be confused with a personal dosing recommendation. Our dosage article provides the full weight-based conversion table.

STOP-Sepsis directly tests whether one day or two days is better

STOP-Sepsis is one of the most informative studies for the pulse-dosing question because its design does not assume that two treatment days are automatically superior.

The Phase 2 trial randomizes adults aged 65 years or older with sepsis to one of three groups:

• one oral fisetin dose of 20 mg/kg;
• two oral doses of 20 mg/kg given 24 hours apart; or
• placebo.

The primary endpoint is change in cardiovascular, respiratory and renal organ dysfunction at day 7. The protocol also measures senescent immune cells, inflammation, safety and later clinical outcomes. ^[9]

That trial design is important conceptually. If the field already knew that two consecutive days were required for human senolysis, there would be little reason to randomize patients between one and two days. STOP-Sepsis instead treats pulse length as an empirical question.

It is also an acute sepsis trial, not a longevity protocol. Its regimen cannot be generalized to healthy adults simply because it uses the same 20 mg/kg number.

Three-day pulses are also part of the human evidence base

The “two days” rule is further undermined by three-day fisetin protocols.

The completed skeletal-health trial used approximately 20 mg/kg/day for three consecutive days every 28 days, repeated for five dosing periods over 20 weeks. ^[4]

TROFFi, a Phase 2 randomized placebo-controlled trial in postmenopausal breast-cancer survivors with reduced physical function after chemotherapy, uses 20 mg/kg/day on days 1–3 of a 14-day cycle for four cycles. ^[10]

TROFFi is especially useful because its rationale and trial design are peer reviewed. It shows that contemporary investigators are testing a repeated three-day pulse every two weeks, not simply recycling a two-day monthly calendar.

How often are fisetin pulses repeated?

There is no single evidence-based repeat interval.

Human protocols use several patterns:

• single short courses for pharmacokinetic or early target-engagement questions;
• one-week spacing between short courses in some COVID-related protocols;
• two-week spacing in TROFFi, FIRST, REVITALiSE and the lower-dose vascular-aging program;
• approximately monthly spacing in AFFIRM, knee-osteoarthritis, skeletal-health, SEN-SURVIVORS and ELDERDIET protocols;
• long-duration monthly treatment in ELDERDIET, where fisetin is only one component of a diet-and-fasting intervention.

The interval is a study-design variable, not a proven biological recovery period. Human data do not establish that senescent cells repopulate on a fixed four-week timetable after fisetin or that any one repeat interval is optimal.

A 2 mg/kg intermittent trial challenges the idea that every pulse must be high dose

The vascular-aging trial in adults aged 65 years or older uses 2 mg/kg/day for three consecutive days, followed by a second three-day course two weeks later. ^[11]

That is one-tenth of 20 mg/kg on a per-kilogram basis.

The trial does not prove that 2 mg/kg is sufficient for senolysis. But it shows that investigators are testing lower intermittent exposure while measuring vascular function, senescence markers and SASP-related biology.

This is another reason not to define pulse dosing as “20 mg/kg or it does not count.”

Does low-dose daily fisetin fail to reach a “senolytic threshold”?

That has not been demonstrated in humans.

No controlled human study has established a fisetin plasma or tissue concentration above which senolysis reliably occurs and below which it does not. The human pharmacodynamic target remains uncertain.

Fisetin LOW is now testing a completely different strategy: 100 mg once daily for seven weeks in adults aged 50 years or older, with chronic inflammation, senescence-related biomarkers, safety and functional measures among the outcomes. ^[12]

That trial is not evidence that daily 100 mg is senolytic. It is evidence that serious human research is testing continuous low exposure rather than assuming that only gram-level pulses are biologically relevant.

Why pulse at all if the optimal schedule is unknown?

The biological rationale still makes sense as a hypothesis.

Senolytic therapy aims to eliminate susceptible senescent cells rather than continuously suppress one target. If brief exposure is sufficient for target-cell elimination, long continuous exposure could be unnecessary. This is the core hit-and-run idea that helped shape the field.

Preclinical fisetin studies also support intermittent treatment as a workable experimental strategy. Murray and colleagues used one week of fisetin treatment, followed by two weeks off, then another treatment week in old mice and reported improved physical function alongside changes in senescence-related skeletal-muscle biology. ^[15]

But that mouse schedule is yet another pattern. It supports intermittent dosing generally; it does not validate a specific human calendar.

Should a fisetin pulse be taken with a high-fat meal?

There is a pharmacokinetic reason to care about formulation and absorption: fisetin has poor water solubility and oral bioavailability can vary substantially. A human crossover study found much greater systemic exposure with a specialized hybrid-hydrogel formulation despite a lower fisetin dose than the unformulated comparator. ^[14]

But that does not prove that an ordinary high-fat meal creates the same effect.

FISEKIN-1 is directly studying this unanswered question by giving each participant a 500 mg fisetin dose under both fed and fasted conditions in randomized crossover visits. ^[13]

Until those data are available, “take the entire fisetin pulse with a fatty meal” should not be presented as a universal trial-validated instruction.

Should the full daily pulse be taken at once or split?

No head-to-head human study has established that a single large administration is superior to dividing the same daily amount.

Individual protocols define their own administration procedures. Some research questions prioritize peak exposure, while others simply specify a total daily weight-based dose.

The correct way to interpret a clinical trial is to follow the administration method described in that trial. It is not evidence-based to convert all studies into a single consumer rule such as “never split the dose.”

What have pulsed human trials actually shown so far?

The clinical outcome evidence remains much less mature than the dosing discussion online suggests.

The completed knee-osteoarthritis trial used approximately 20 mg/kg/day for two days, followed by 28 days off between each of three two-day treatment cycles, as described in the OARSI 2025 conference abstract. The posted results did not show a consistent fisetin advantage across the main clinical and biomarker outcomes. ^{[7] [21]}

COVID-FIS used approximately 20 mg/kg/day on days 0, 1, 8 and 9; its final registry record reports termination for futility in that specific nursing-home COVID-19 population. ^[5]

Other important pulse-dosing studies remain ongoing or have not produced definitive peer-reviewed efficacy results. Fisetin HIGH is still primarily a pharmacokinetic, safety and biomarker study, while STOP-Sepsis and TROFFi are active trials. ^{[8] [9] [10]}

So the human data do not support describing any pulse calendar as a proven anti-aging treatment.

What about safety and medication interactions during a pulse?

High-dose pulse trials do not simply hand participants capsules and send them home with a calendar.

Clinical protocols use eligibility screening, medication review, laboratory monitoring and predefined exclusion criteria. Some Mayo fisetin trials specifically require potentially interacting medications to be held around dosing if investigators judge that this can be done safely. ^[3]

That is an important part of the protocol—not an instruction for readers to stop prescription medication on their own.

Short treatment windows may reduce cumulative exposure compared with continuous high-dose use, but there is no rigorous human head-to-head study proving that pulsing is globally safer than daily fisetin.

For medication-specific issues, see our fisetin drug-interaction review and fisetin safety review.

Should you follow a two-day monthly fisetin protocol?

A two-day monthly schedule is a legitimate research pattern used in some human trials. It is not a validated universal treatment protocol.

The current evidence does not establish:

• that two days is better than one or three;
• that 28 days is the optimal off-period;
• that 20 mg/kg is the optimal dose for healthy adults;
• that monthly pulses reliably clear senescent cells in humans;
• that taking a pulse with a high-fat meal improves clinical outcomes;
• that repeating pulses for years is safe or beneficial.

The existence of a clinical-trial schedule tells us what researchers are testing. It does not turn that schedule into a personal anti-aging prescription.

Further reading: our broader clinician's guide to the full evidence. Research schedules remain investigational.

Bottom line

Fisetin pulse dosing is a real and important part of human senolytic research, but there is no single protocol that deserves to be presented as the Mayo Clinic fisetin schedule.

Approximately 20 mg/kg/day is common, yet trials use one-, two- and three-day treatment windows, lower intermittent dosing, weight-banded fixed-milligram schedules and monthly courses embedded in larger lifestyle programs. STOP-Sepsis compares one versus two doses; TROFFi, FIRST and REVITALiSE use two-week cycles; skeletal-health and several frailty protocols use roughly monthly cycles; and the vascular-aging study uses only 2 mg/kg/day intermittently. The hit-and-run rationale remains scientifically plausible. What is not established is the optimal human dose, pulse length, interval, meal timing or long-term schedule.

That uncertainty is not a weakness in the evidence review. It is the evidence.