Senolytics are molecules designed to eliminate senescent cells, the “zombie” cells that accumulate with age and keep tissues in a state of inflammation. Since 2019, eight published trials have tested these senolytics in humans, from pulmonary fibrosis to diabetic macular edema. This review goes through each of these trials, what they actually measured and what remains to be shown before any use outside a research protocol.
In brief – Senolytics are a class of experimental drugs that trigger the death of senescent cells without harming healthy cells. In humans, the dasatinib + quercetin combination reduced the number of senescent cells in fat tissue within 11 days (Hickson 2019, n = 9) and improved walking in patients with pulmonary fibrosis in an open-label study (Justice 2019, n = 14). But the two available randomized placebo-controlled trials are neutral on their primary endpoint: no effect on bone resorption in 60 postmenopausal women (Farr 2024) and a non-significant gain in vision with the ocular senolytic UBX1325 (Klier 2025, n = 65). The systematic review by Trivedi (2026) concludes that senolytics remain research treatments, feasible and generally well tolerated over a few weeks, with no proof of clinical efficacy or long-term safety.
Senolytics: definition and main molecules
A senolytic is a molecule that selectively kills senescent cells, meaning cells that have stopped dividing but refuse to die. These cells secrete a cocktail of inflammatory signals called the SASP (senescence-associated secretory phenotype), which damages neighboring tissue and feeds inflammaging. The term was proposed in 2015 by the Mayo Clinic team (Zhu et al., Aging Cell), which identified the first two active molecules: dasatinib, an anticancer drug used in some leukemias, and quercetin, a flavonoid found in onions and apples.
Senolytics should not be confused with senomorphics. The former destroy the senescent cell; the latter, such as rapamycin or metformin, leave it in place but dampen its inflammatory secretions. The senolytic candidates most studied in humans are the dasatinib + quercetin combination (written D + Q), fisetin, another flavonoid, and UBX1325 (foselutoclax), an inhibitor of the BCL-xL protein injected into the eye. Navitoclax and piperlongumine, two other senolytics, have only been tested on cells or animals.
How senolytics work: the mechanism
Senescent cells survive because they activate anti-apoptotic pathways, molecular “shields” that researchers call SCAPs. Senolytics target these shields for a few hours, long enough for the senescent cell to tip into programmed death, while normal cells, which do not depend on these pathways, survive.
- BCL-2 / BCL-xL family: the target of navitoclax and UBX1325, proteins that block the triggering of apoptosis.
- Tyrosine kinases and ephrin receptors: the targets of dasatinib, mainly in senescent fat cell precursors.
- PI3K/AKT and HIF-1α pathways: the targets of quercetin and fisetin, more in senescent endothelial cells.
- “Hit-and-run” dosing: D + Q have a half-life under 11 hours, which allows intermittent dosing (2 to 3 consecutive days per month) and limits exposure.
In mice, the evidence for senolytics is solid. Baker et al. (Nature, 2016) showed that genetically clearing p16-positive cells extends median lifespan and delays damage to the kidneys, heart and fat tissue. Xu et al. (Nature Medicine, 2018) then obtained, with D + Q given to mice aged 24 to 27 months, a 36% increase in post-treatment survival and better walking speed and endurance. This series of results is what launched the human trials.
What the trials of senolytics in humans prove
No trial has yet shown a robust clinical benefit of senolytics in humans: the positive signals come from open-label studies with small numbers, and the two published randomized placebo-controlled trials are neutral on their primary endpoint. Here is the detail, study by study.
The first trial, Justice et al. (EBioMedicine, 2019), gave D + Q to 14 patients with idiopathic pulmonary fibrosis for 3 weeks, with no control group. The 6-minute walk distance, walking speed over 4 meters (13 ft) and the chair-rise test improved significantly, but lung function did not move. A few months later, Hickson et al. (2019) provided the first direct evidence in humans: in 9 diabetic patients with kidney disease, 3 days of D + Q reduced p16- and p21-positive cells in fat and skin within 11 days, and lowered circulating SASP factors (IL-6, IL-1α, MMP-9).
The controlled trials then tempered the enthusiasm. Nambiar et al. (2023) randomized 12 patients with pulmonary fibrosis to D + Q or placebo: the treatment proved feasible with no serious adverse event, but physical function did not differ between groups, and sleep disturbances and anxiety affected 4 of 6 patients on D + Q versus 0 of 6 on placebo. In 5 patients with early Alzheimer’s disease, Gonzales et al. (Nature Medicine, 2023) found dasatinib in the cerebrospinal fluid of 4 participants, but not quercetin, with no cognitive change at 12 weeks. Along the same lines, Millar et al. (2025) followed 12 adults at risk of Alzheimer’s on D + Q for 12 weeks: the MoCA cognitive score gained 1 point, a non-significant difference.
The largest randomized trial of senolytics to date, Farr et al. (Nature Medicine, 2024), followed 60 postmenopausal women through 20 weeks of intermittent D + Q. The bone resorption marker CTx did not change compared with the control group. The formation marker P1NP rose by 16% at 2 and 4 weeks, then the effect vanished by 20 weeks. Only the third of women with the highest senescent cell burden saw their radius bone density increase by 2.7%. In ophthalmology, after a reassuring phase 1 (Crespo-Garcia et al., Nature Medicine, 2024), Klier et al. (NEJM Evidence, 2025) compared one injection of UBX1325 with a sham injection in 65 patients with diabetic macular edema: the gain in visual acuity was 5.6 letters at 48 weeks, with a confidence interval that included zero.
| Trial | Molecule and indication | Participants | Main result |
|---|---|---|---|
| Justice 2019, open-label | D + Q, pulmonary fibrosis | 14 | 6-minute walk and chair rise improved; lung function unchanged |
| Hickson 2019, open-label | D + Q, diabetic kidney disease | 9 | Senescent cells in fat tissue reduced within 11 days |
| Nambiar 2023, randomized | D + Q vs placebo, pulmonary fibrosis | 12 | Feasible, no difference in physical function |
| Gonzales 2023, open-label | D + Q, early Alzheimer’s | 5 | Dasatinib detected in the brain, cognition stable |
| Farr 2024, randomized | D + Q vs control, postmenopausal bone | 60 | Primary endpoint neutral; radius density +2.7% in the high senescent burden subgroup |
| Millar 2025, open-label | D + Q, Alzheimer’s risk | 12 | MoCA score +1 point, non-significant |
| Klier 2025, randomized | UBX1325 vs sham, macular edema | 65 | +5.6 letters of acuity, non-significant |
The systematic review by Trivedi et al. (British Journal of Clinical Pharmacology, 2026) sums up the situation: six completed studies, measurable biological effects, acceptable tolerability over a few weeks, but sample sizes too small and follow-ups too short to conclude on clinical efficacy or long-term safety. The authors class senolytics among “investigational” treatments.
In practice: where natural senolytics and supplements stand
No dietary supplement sold today has shown a senolytic effect in humans. Quercetin alone has never been tested as a senolytic in the clinic: in every trial, it accompanies dasatinib, a prescription drug reserved for leukemias, at doses of 1250 mg per day, 2 to 5 times the amount in a typical supplement. Fisetin is the most advanced candidate among the flavonoids: several randomized trials are under way in frail or overweight older adults, but no final result has been published. Apigenin acts more as a senomorphic in cell models.
The most interesting signal for prevention does not come from senolytics: Englund et al. (Aging Cell, 2021) measured, in older adults, a significant drop in the senescence markers p16, p21 and TNF-α in T cells after 12 weeks of structured exercise. In other words, regular physical activity remains to date the only intervention with a measured effect on senescent cell burden in healthy humans. This reading matches the validated levers against inflammaging and the pillar page devoted to cellular senescence.
One biological nuance is worth knowing. A French team led by Dmitry Bulavin showed in 2020, in mice, that clearing senescent cells from the liver worsened the loss of liver function instead of correcting it (Grosse et al., Cell Metabolism, 2020). Senescence also acts as a natural brake on cancer by stopping damaged cells from dividing, as the National Cancer Institute points out. Not every senescent cell should therefore be eliminated, and tissue selectivity remains an open challenge for senolytics.
| Approach | Status | Human evidence | Point of caution |
|---|---|---|---|
| Dasatinib + quercetin | Repurposed prescription drug, phase 1 and 2 trials | Senescent burden reduced; clinical endpoints neutral in randomized trials | Adverse effects of dasatinib (digestive problems, bruising, sleep disturbances) |
| Oral fisetin | Dietary supplement, trials under way | No published result | Trial doses (20 mg/kg) far above supplement amounts |
| UBX1325 (foselutoclax) | Drug candidate, phase 2 | Non-significant trend on vision | Intraocular injection, specialist use |
| Structured exercise | Accessible to everyone | p16/p21 markers reduced in 12 weeks (Englund 2021) | Modest effect, but measured in humans |
Protocol: what to check before considering senolytics
The only legitimate way to take senolytics today is through a supervised clinical trial. Here are the points to check, in order, if the subject interests you.
- Find a trial: the ClinicalTrials.gov database lists more than 25 ongoing studies on senolytics and around thirty on fisetin, some of them recruiting in Europe.
- Never obtain dasatinib without a prescription: its documented adverse effects include pleural effusions, drops in platelet counts and heart rhythm disorders.
- Go over the doses with a doctor: the protocols use 100 mg of dasatinib and 1250 mg of quercetin per day, for 2 to 3 consecutive days, followed by a break of several weeks.
- Interpret senescence tests with caution: measurements of p16 in T cells remain research tools, with no validated threshold for an individual.
- Act on what is proven: 12 weeks of structured exercise lowered senescence markers in older adults; it is the best-documented daily habit.
The results of Farr (2024) suggest that senolytics might mainly benefit people whose senescent cell burden is already high. If this hypothesis is confirmed, the future of these treatments will look like biomarker-targeted medicine, not an anti-aging pill for everyone.
Frequently asked questions about senolytics
What is the difference between senolytics and senomorphics?
Senolytics destroy senescent cells by blocking their survival pathways, for example the dasatinib + quercetin combination or UBX1325. Senomorphics, such as rapamycin or metformin, leave these cells alive but reduce their inflammatory secretions (SASP). The former are given in short, spaced-out courses, the latter continuously. Neither class has a validated indication for aging.
Have senolytics proven an anti-aging effect in humans?
No. The published human trials show that the dasatinib + quercetin combination reduces the number of senescent cells in fat and skin within 11 days (Hickson 2019, 9 patients). However, the two randomized placebo-controlled trials (Farr 2024 on bone, Klier 2025 on vision) did not meet their primary endpoint. Senolytics therefore remain experimental treatments with no proof of clinical benefit.
Does quercetin as a supplement count as a senolytic?
Not at the doses of common supplements. In the trials, quercetin is given at 1250 mg per day and always combined with dasatinib, which provides most of the effect on certain senescent cells. No study has tested quercetin alone as a senolytic in humans, and its oral bioavailability is low. A 500 mg quercetin supplement therefore has no demonstrated senolytic effect.
What are the side effects of senolytics?
In the randomized trial by Nambiar (2023), patients on dasatinib + quercetin reported more non-serious adverse events than the placebo group (65 versus 22), mostly digestive problems, skin bruising and sleep disturbances. Dasatinib, used long term in oncology, carries a risk of pleural effusions and drops in platelet counts. Senolytics in short courses seem better tolerated, but there is no follow-up beyond a few months.
Can you reduce your senescent cells without medication?
Partly, yes. Englund et al. (2021) measured a significant drop in the senescence markers p16 and p21 in the T cells of older adults after 12 weeks of structured exercise. Regular physical activity is today the only intervention with a documented effect on senescent cell burden in healthy humans. Natural senolytics such as fisetin are being evaluated, with no published result so far.
Medical disclaimer. The information on this page is provided for informational purposes only and does not constitute medical advice. It does not replace a consultation. Dasatinib is a prescription drug reserved for specific oncology indications: never take it as self-medication, and never start any senolytic protocol outside a clinical trial supervised by a physician. Ask a healthcare professional before changing your diet, taking dietary supplements or starting a new practice, especially if you have a medical condition, are pregnant or are under treatment. Dietary supplements do not replace a balanced diet or medical follow-up.
