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Key takeaways
• The trial-validated dose is 20 mg/kg for two consecutive days, repeated every 28 days (2,3,4,5,6,7). For a 70 kg adult this is ~1,400 mg on day 1, ~1,400 mg on day 2, then no fisetin for four weeks.
• Most commercial capsules deliver 100–500 mg per capsule and recommend daily use. This dosing pattern matches neither the pulsed trial protocol nor the chronic mouse chow-feeding model used in the 2018 lifespan paper.
• Continuous daily dosing has independent flavonoid-antioxidant rationale but is not the senolytic protocol. Reading benefit language on a daily capsule as if it were the senolytic evidence is a category error.
• Bioavailability is a floor. An unformulated 1,000 mg oral dose produces a plasma Cmax of just 9.97 ng/ml (9) — 30–150-fold below the in vitro senolytic window. Doubling the dose does not double the effect.
• Take with a fat-containing meal. Fisetin is fat-soluble; co-ingestion with dietary fat is the simplest practical intervention for improving absorption.
• The practical middle ground: if you have a commercial capsule product, the trial-aligned use is to take a burst of 3–4 capsules on day 1 and day 2, then stop for four weeks — not one capsule daily indefinitely.
Quick answer
The dose used in every published human fisetin trial is 20 mg/kg per day for two consecutive days, then 28 days off. For a 70 kg adult, that is approximately 1,400 mg on day 1, 1,400 mg on day 2, then no fisetin for four weeks. Almost no commercial capsule product recommends this schedule. Most recommend a daily 100–500 mg capsule, which matches no published efficacy protocol. This is the single most important editorial fact about fisetin dosing in 2026. This article walks through the trial evidence, the mouse studies, the bioavailability ceiling, and the practical implications. For the full clinical context, see our complete clinician’s guide.
The trial-validated dose — where 20 mg/kg × 2 days comes from
Six human trials — AFFIRM, COVID-FIS, COVFIS-HOME, the cartilage degeneration trial, PROFFi, and Fisetin HIGH — use variants of the same dosing protocol (2,3,4,5,6,7). The load-bearing dose is 20 mg/kg per day for two consecutive days, cycled at monthly intervals. This choice was made deliberately by the Mayo Clinic translational geroscience group who designed the founding senolytic protocols, and it reflects three specific considerations.
1. The hit-and-run pharmacology
Senescent cells regenerate slowly. Once cleared, weeks pass before the population rebuilds. A short high-dose pulse briefly pushes fisetin concentration into the senolytic window in tissue, tips senescent cells past their apoptotic threshold, and then falls away — allowing off-target concerns and metabolic burden to resolve before the next pulse. This mirrors the founding dasatinib plus quercetin protocol (three consecutive days per month) developed by James Kirkland and colleagues.
2. Mouse-to-human dose translation
The founding Yousefzadeh 2018 mouse experiments used oral gavage at 100 mg/kg (1). Standard interspecies dose conversion using the FDA-recommended body surface area factor of 12.3 for mice yields a human equivalent dose of approximately 8 mg/kg (11). The Mayo Clinic protocols set the human dose at 20 mg/kg — roughly 2.5-fold above the strictly scaled human equivalent — to allow margin against interspecies bioavailability differences and against the flavonoid absorption ceiling.
3. The single high-dose pulse strategy for poorly bioavailable compounds
Unformulated fisetin has poor oral bioavailability (9). Given a fixed pharmacokinetic ceiling, the way to achieve the highest tissue concentration is to give the largest tolerated single dose. Two consecutive days provides two absorption windows in quick succession, doubling the tissue exposure time above threshold without the safety concerns of chronic high-dose intake. This is a pragmatic response to the bioavailability problem.
What 20 mg/kg × 2 days looks like in practice
The table below translates the trial dose into practical amounts by body weight.
|
Body weight |
Dose per day (mg) |
Total per pulse (2 days) |
Approx. 500 mg capsules per day |
|
50 kg (110 lb) |
1,000 |
2,000 |
2 capsules |
|
60 kg (132 lb) |
1,200 |
2,400 |
2–3 capsules |
|
70 kg (154 lb) |
1,400 |
2,800 |
3 capsules |
|
80 kg (176 lb) |
1,600 |
3,200 |
3–4 capsules |
|
90 kg (198 lb) |
1,800 |
3,600 |
4 capsules |
|
100 kg (220 lb) |
2,000 |
4,000 |
4 capsules |
The schedule: two consecutive days at this dose, then no fisetin for the following 28 days. Then repeat. Approximately 12 pulses per year.
The dose is administered as a single daily amount, not split across the day — the pharmacokinetic aim is a high plasma peak, and splitting reduces Cmax without extending the duration above the senolytic threshold. All doses should be taken with a fat-containing meal to improve absorption (9). Our dedicated pulse dosing article walks through the exact practical schedule with meal-timing and monitoring notes.
Why daily capsules don’t match the trial protocol
Almost every commercial fisetin product recommends 100 to 500 mg once daily, sometimes twice daily, taken continuously. This dosing pattern differs from the trial protocol in three specific ways.
1. The total dose per pulse is lower
A 500 mg daily capsule over 60 days delivers a total of 30,000 mg. Two pulses of the trial protocol over the same 60 days deliver approximately 5,600 mg total (for a 70 kg adult). Daily dosing therefore delivers more total fisetin, but distributed across the entire period rather than concentrated into brief high-plasma-peak pulses. Because the senolytic window is a concentration threshold, not a cumulative exposure, this changes what the dose is expected to do.
2. Plasma peaks are lower
Single doses of 500 mg produce plasma Cmax values proportionally below those achieved by 1,400 mg pulses (9). Since fisetin’s senolytic activity depends on reaching a threshold concentration in tissue, lower plasma peaks translate to lower likelihood of hitting the therapeutic window. Continuous exposure at sub-threshold concentrations does not accumulate into effective concentrations because fisetin has a short plasma half-life (<2 hours) and undergoes rapid biliary elimination.
3. No off-cycle
The 28-day off-period between trial pulses is not incidental — it is the biological premise. Senescent cells regenerate slowly, so persistent senolytic pressure is not necessary. Daily dosing removes the off-cycle and, in doing so, changes the pharmacology from hit-and-run to continuous exposure. The clinical implications of continuous exposure at low concentration are unstudied.
None of this means that daily capsule dosing is harmful. It means that daily capsule dosing is not a senolytic protocol as defined by the published trials. If the goal is dietary flavonoid intake at supplemental doses, daily capsules are a defensible format. If the goal is senolytic effect as tested in the Mayo Clinic protocols, the daily-capsule format is a mismatch. See our detailed pulse dosing article for the alignment strategy.
The mouse chow model — the other reference point
The Yousefzadeh 2018 lifespan-extension arm used a different dosing pattern: 500 mg/kg in chow, administered continuously from 85 weeks of age until end of life (1). This is not a pulsed protocol — it is chronic dietary exposure at high concentration in food. Scaled to a 70 kg human by the same interspecies conversion, this corresponds to roughly 40 mg/kg per day continuously, or approximately 2,800 mg per day.
No commercial capsule delivers this dose continuously, nor should it — the safety data at this dose in humans do not exist. But it is worth naming because the mouse-lifespan story rests on chronic feeding, not on the pulsed protocol. When product pages cite "lifespan extension" and "healthy aging," the underlying evidence is chronic high-dose chow feeding in mice, not the human pulsed protocol. The two are different experiments that answer different questions.
The bioavailability ceiling — the reason more isn’t proportionally better
The Krishnakumar 2022 human pharmacokinetic study is the load-bearing paper for understanding fisetin dose-response (9). It gave 15 healthy adults 1,000 mg of unformulated fisetin and measured plasma over 12 hours. The peak concentration was 9.97 ng/ml (~35 nM) — approximately 30- to 150-fold below the in vitro senolytic window of 1 to 5 μM. Fisetin was undetectable in plasma beyond two hours.
This has three consequences for dose thinking. First, doubling the dose does not double the plasma peak. Higher single doses produce disproportionately smaller absorption gains. Second, the trial protocol’s two consecutive pulses (rather than one huge dose) is a workaround for this ceiling — two absorption windows instead of one, without pushing single-dose absorption into diminishing returns. Third, formulation strategies (hydrogel, liposomal, phytosomal) have been shown to break through the ceiling by improving intestinal uptake — the Krishnakumar paper reported a 23-fold Cmax increase with a hydrogel formulation. Our dedicated bioavailability article walks through the pharmacokinetics in detail, and our liposomal fisetin article evaluates the formulation options.
Practical dosing schedules — three defensible options
Below are three dosing strategies with the honest evidence tier for each. Choose whichever matches your goal.
Option A — Trial-aligned pulsed protocol
The strongest match to published human trials. Take 20 mg/kg on day 1 and again on day 2 of each month, then stop. Total dose per pulse: approximately 1,400 mg per day for a 70 kg adult. Take with a fatty meal. Cycle monthly, roughly 12 pulses per year. Evidence tier: matches every ongoing human trial. Not proven efficacious in humans until AFFIRM and PROFFi publish.
Option B — Modest continuous flavonoid intake
A defensible dietary-flavonoid-supplementation approach. Take 100 to 250 mg daily with a fatty meal, treating fisetin as a concentrated dietary polyphenol rather than a senolytic. Evidence tier: consistent with general flavonoid pharmacology. Does not correspond to any published senolytic protocol. Reasonable for readers who want the antioxidant identity without commitment to the pulsed schedule.
Option C — Dietary approach only
For readers who prefer whole-food strategies, the strongest evidence-aligned approach is a strawberry-rich, polyphenol-rich diet without capsule supplementation. Strawberries deliver approximately 40 mg fisetin per 250 g serving. This is not a senolytic dose, but the epidemiology of flavonol-rich diets and cardiovascular mortality provides independent support. Our foods high in fisetin article ranks the sources.
What we still don’t know
• Whether the 20 mg/kg × 2 days protocol is actually optimal for humans. It was set on translational reasoning; the AFFIRM and Fisetin HIGH trials are the first tests.
• Whether continuous low-dose exposure produces any senolytic benefit or purely antioxidant benefit. No trial has been designed to distinguish these.
• Whether specific indications require different doses. All ongoing trials use the same dose regardless of endpoint (frailty, cartilage, cognitive, inflammation).
• Whether bioavailability-enhanced formulations should proportionally reduce the dose. If a hydrogel formulation increases Cmax 23-fold, does the reader need one-twentieth the dose? This has not been established.
Bottom line
The published trial dose is 20 mg/kg for two consecutive days, every 28 days. That is approximately 1,400 mg per day, twice per month, for a 70 kg adult. Most commercial capsules do not deliver this schedule and do not recommend this pattern. Readers who want to align with the trial pipeline should take burst doses of 3 to 4 capsules on day 1 and day 2, then stop for four weeks. Readers who prefer a dietary flavonoid approach can take 100 to 250 mg daily, understanding that this is not a senolytic protocol. Readers who prefer whole foods can prioritise strawberries and other polyphenol-rich fruits. All three approaches are defensible; only one matches the trial evidence for the senolytic claim. For the practical protocol walk-through, see our dedicated pulse dosing article. For evidence context, see our dedicated senolytic article.
Frequently asked questions
What is the standard fisetin dose?
There is no single "standard" dose. Every published trial uses 20 mg/kg × 2 days pulsed. Most capsules recommend 100 to 500 mg daily. The two protocols answer different questions.
Is 500 mg fisetin enough?
For a daily flavonoid-antioxidant approach, yes — 500 mg is a substantial dose above dietary intake. For the trial-validated senolytic protocol, 500 mg on a single day matches roughly a 25 kg body weight — well below the adult 70 kg target dose.
Is 1,000 mg fisetin too much?
Not for the pulsed protocol. The Krishnakumar 2022 PK study administered 1,000 mg as a single dose with no reported adverse events (9). Trial doses at 20 mg/kg exceed 1,000 mg for adults above 50 kg. Continuous daily 1,000 mg dosing has not been formally characterised for long-term safety.
Should I take fisetin with food?
Yes, with a fat-containing meal. Fisetin is fat-soluble; co-ingestion with dietary fat modestly improves absorption of an unformulated capsule. See our how and when to take fisetin article for the practical guidance.
Can I split the pulsed dose across the day?
The trial protocol calls for a single daily dose. Splitting the dose reduces plasma Cmax without extending the duration above the senolytic threshold. The pharmacological aim of the pulse is a high plasma peak, not sustained low exposure.
What if I miss a pulse?
Resume the next scheduled pulse. Do not double up. Missing a pulse means one fewer senolytic cycle in a year — the effect is small over multi-year timescales.
Is there a dose above which fisetin becomes harmful?
A precise upper limit has not been established in humans. The Mayo Clinic protocol dose of 20 mg/kg × 2 days has been well tolerated. Above this dose, safety data are scarce. Chronic daily dosing at very high doses (multiple grams per day) has not been tested and should not be self-administered.
References
1. Yousefzadeh MJ, Zhu Y, McGowan SJ, et al. Fisetin is a senotherapeutic that extends health and lifespan. EBioMedicine. 2018;36:18-28. https://pmc.ncbi.nlm.nih.gov/articles/PMC6197652/
2. AFFIRM: Alleviation by Fisetin of Frailty, Inflammation, and Related Measures in Older Women (NCT03430037). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT03430037
3. COVID-FIS: Phase 2 Placebo-Controlled Pilot Study of Fisetin in Older Adults in Nursing Homes (NCT04537299). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT04537299
4. COVFIS-HOME: Home-Based Study of Fisetin in Community-Dwelling Adults With COVID-19 (NCT04771611). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT04771611
5. A Trial of Fisetin to Treat Cartilage Degeneration in Osteoarthritis (NCT04210986). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT04210986
6. PROFFi: Prevention of Frailty with Fisetin and Exercise in Breast Cancer Survivors (NCT06113016). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT06113016
7. Pilot Trial of Fisetin in Healthy Volunteers and Older Patients with Multimorbidity — Fisetin HIGH (NCT06431932). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT06431932
8. Verdoorn BP, Evans TK, Hanson GJ, et al. Fisetin for COVID-19 in skilled nursing facilities: senolytic trials in the COVID era. J Am Geriatr Soc. 2021;69(11):3023-3033. https://pmc.ncbi.nlm.nih.gov/articles/PMC8447437/
9. Krishnakumar IM, Jaja-Chimedza A, Joseph A, et al. Enhanced bioavailability and pharmacokinetics of a novel hybrid-hydrogel formulation of fisetin orally administered in healthy individuals. J Nutr Sci. 2022;11:e74. https://doi.org/10.1017/jns.2022.72
10. Murray KO, Mahoney SA, Venturini S, et al. Intermittent supplementation with fisetin improves physical function and decreases cellular senescence in skeletal muscle with aging. Aging Cell. 2025;24:e70114. https://doi.org/10.1111/acel.70114
11. Nair AB, Jacob S. A simple practice guide for dose conversion between animals and human. J Basic Clin Pharm. 2016;7(2):27-31. https://pmc.ncbi.nlm.nih.gov/articles/PMC4804402/
12. Niedernhofer LJ, Robbins PD. Fisetin as a senotherapeutic agent: evidence and perspectives for age-related diseases. Mech Ageing Dev. 2024;220:111995. https://doi.org/10.1016/j.mad.2024.111995
13. Khosla S. Translating senolytics from mice to humans. GeroScience. 2025. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12759346/