Fisetin
A natural compound found in strawberries that clears out your body's "zombie cells" — old, damaged cells that refuse to die and cause inflammation. The most potent natural senolytic studied so far.
As you age, some of your cells stop working properly but won't die. These "senescent" cells pile up and pump out inflammatory chemicals that damage surrounding tissue. Fisetin selectively kills these zombie cells while leaving healthy cells alone — a process called senolysis.
Good for you if: You're interested in longevity and want to address one of the key drivers of aging — senescent cell accumulation. Especially relevant if you're over 40.
Dive deeper into the researchCommon side effects
- Mild stomach discomfort at very high doses
- Possible mild anti-platelet effect — caution with blood thinners
- No serious adverse events reported in any human trial to date
What does fisetin do?
Throughout your life, some cells get damaged beyond repair. Normally, they'd self-destruct (apoptosis). But some don't — they become senescent cells, often called "zombie cells." They stop working but stay alive, pumping out inflammatory chemicals that damage the cells around them.
By age 50+, these zombie cells build up significantly. They contribute to joint pain, chronic inflammation, and many age-related diseases. Fisetin was ranked the #1 natural senolytic in a Mayo Clinic study that tested 10 compounds — it cleared up to 50–60% of senescent cells in animal tissues.
What can you expect?
- Less chronic inflammation — fewer senescent cells means less inflammatory signalling
- Better physical function — mice treated with fisetin showed improved strength and endurance
- Slower aging markers — reduced senescent cell burden improves multiple aging hallmarks
- Potential joint and tissue health benefits — less inflammatory damage to cartilage and connective tissue
How to take it
20 mg per kg of your body weight, for 2 consecutive days per month. For a 65 kg person, that's about 1300 mg/day for 2 days. Take with a meal containing fat.
Alternatively, 100–500 mg daily provides ongoing anti-inflammatory and antioxidant benefits, though this lower dose doesn't reach the peak senolytic concentrations of the burst protocol.
Why only 2 days? Senolytics aren't meant for daily use. You take a high dose to clear accumulated zombie cells, then wait for them to slowly re-accumulate over weeks before the next round. Monthly or quarterly protocols are most common.
When to avoid it: If you're on anticoagulants (blood thinners), use caution as fisetin has mild anti-platelet activity. May inhibit CYP3A4 at very high doses — separate from medications by 2+ hours.
Which form to buy?
Fisetin is a fat-soluble flavonoid, so absorption matters. Here's what to look for:
- Source: Look for supplements standardised from smoke tree bark or Japanese wax tree — these are the richest natural fisetin sources
- Bioavailability: Take with a fatty meal. Some formulations include piperine (black pepper) or use liposomal delivery for better absorption
- Label check: Confirm the stated mg is actual fisetin content, not total plant extract weight
- Availability in India: Primarily through online import (iHerb, Amazon). Budget ₹1,500–3,000/month for quality fisetin
You can't get a senolytic dose from food — strawberries contain only about 160 micrograms per gram, meaning you'd need about 8–10 kg of strawberries. Supplements are necessary for the high-dose protocol.
Want to see if fisetin is actually working for you?
eterni tracks your inflammation markers before and after — so you can see the impact of your senolytic protocol.
Get early accessFrequently Asked Questions
What is the fisetin senolytic protocol?
Take 20 mg per kg of your body weight for 2 consecutive days, once per month. For a 65 kg person, that's about 1300 mg per day for 2 days. Take with a fatty meal. The monthly interval is based on the time it takes for senescent cells to re-accumulate. Some people do quarterly instead.
Fisetin vs quercetin — which is better?
For senolytic activity alone, fisetin is about 3–5× stronger than quercetin. However, quercetin combined with the prescription drug dasatinib (D+Q) is the most powerful senolytic combo tested in humans. Without a prescription, fisetin is the better standalone option. Quercetin has broader anti-inflammatory and anti-allergy benefits beyond senolytics.
How much fisetin should I take?
For the senolytic burst: 20 mg/kg × 2 days per month. For daily antioxidant support: 100–500 mg/day. Both require taking with fat-containing food. The burst protocol is what clinical trials use and is preferred for actual senescent cell clearance.
Is fisetin safe?
Yes — no serious side effects have been reported in any human trial, even at the high senolytic dose. Some people experience mild stomach discomfort. If you're on blood thinners, check with your doctor due to fisetin's mild anti-platelet activity.
How it works in your body
Senescent cells survive because they upregulate anti-apoptotic proteins (BCL-2, BCL-XL) and pro-survival pathways (PI3K/AKT). Fisetin inhibits both, selectively removing the survival advantage that keeps zombie cells alive while leaving healthy cells unaffected.
Beyond senolytics, fisetin also suppresses NF-κB-driven inflammatory signalling and provides direct antioxidant activity, reducing oxidative stress that contributes to new senescence.
What the studies show
- Mayo Clinic ranking: Fisetin ranked #1 out of 10 natural senolytic candidates, clearing 50–60% of senescent cells in aged mouse tissues (Yousefzadeh et al., 2018)
- Physical function: Fisetin-treated mice showed improved strength, endurance, and healthspan measures vs controls
- Human trials: Phase I/II trials at Mayo Clinic using 20 mg/kg for 2 days in patients with diabetic kidney disease — well-tolerated with no serious adverse events
- Ongoing research: Multiple trials assessing fisetin for osteoarthritis, frailty, and COVID-19 complications
Side effects & safety
Fisetin has one of the cleanest safety profiles of any longevity supplement being studied.
- GI discomfort — Mild stomach upset at very high doses. Taking with food minimises this.
- Anti-platelet activity — Mild effect on blood clotting. If you're on warfarin or other anticoagulants, space fisetin from your medication and consult your doctor.
- CYP3A4 inhibition — At very high doses, fisetin may slow down this liver enzyme. Separate from medications by 2+ hours.
- No serious adverse events — Across all human trials to date, no significant safety concerns have emerged at the 20 mg/kg dose.
Who should skip it: People on anticoagulants (without doctor supervision), pregnant or breastfeeding women (insufficient data). Otherwise, fisetin is considered very safe.
Which labs to check
There's no direct test for senescent cell burden, but you can track downstream inflammation markers:
- hsCRP — general inflammation that should decrease as senescent cells are cleared
- IL-6 — a key inflammatory cytokine driven by senescent cell secretions
- Fasting glucose & insulin — senescent cell clearance improves metabolic health in animal studies
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eterni connects your lab results, supplements, and retests — so you can see the trajectory, not just a snapshot.
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