Senolytics: The Science of Clearing Zombie Cells to Reverse Aging

If you follow longevity science, you have almost certainly heard the term “zombie cells.” The metaphor is vivid, and it is also remarkably accurate. As you age, a growing population of cells in your body stop dividing, refuse to die, and begin poisoning the tissue around them. They are called senescent cells, and they are one of the most exciting targets in modern aging research.

Senolytics are drugs and compounds designed to selectively eliminate these dysfunctional cells. The field is still young, the term itself was only coined in 2015, but the trajectory is unmistakable. In animal studies, clearing senescent cells has extended lifespan by 20 to 30 percent, restored organ function, improved physical performance, and even reversed visible signs of aging. Some researchers believe senolytics could eventually rival or surpass GLP-1 drugs in their impact on human health, not for weight loss, but for the far more fundamental problem of aging itself.

This guide covers the science honestly. What we know. What we don't know. What's available now, what's still experimental, and whether any of it is ready for you to act on today. The longevity space is flooded with premature certainty and supplement marketing. This is not that. This is what the research actually shows, where the gaps are, and how to think about senolytics if you are serious about optimizing your healthspan.

What are senescent cells?

To understand senolytics, you first need to understand the problem they are designed to solve. Senescent cells are cells that have permanently stopped dividing but have not undergone apoptosis, the programmed cell death process that normally removes damaged or dysfunctional cells from your body. They are alive, metabolically active, and deeply problematic.

Cell senescence is not inherently bad. It evolved as a protective mechanism. When a cell sustains DNA damage that could lead to cancer, senescence acts as a brake, halting division so the damage cannot propagate. During wound healing, senescent cells play a role in tissue remodeling and signaling to the immune system. In embryonic development, senescence helps shape tissues and organs. The problem is not senescence itself. The problem is what happens when senescent cells accumulate.

In a young, healthy body, the immune system efficiently identifies and clears senescent cells. Macrophages, natural killer cells, and T cells recognize senescent markers and eliminate these cells before they can cause lasting damage. This surveillance system works well in youth. But as you age, the immune system itself becomes less efficient, a process called immunosenescence. At the same time, the rate of new senescent cell formation increases because aging tissues sustain more DNA damage, experience more oxidative stress, and encounter more replicative exhaustion. The result is a growing imbalance: senescent cells are being produced faster than the immune system can clear them.

By age 60, senescent cells may comprise 5 to 15 percent of cells in some tissues. That percentage might sound small, but the damage they inflict is disproportionate to their numbers. This is because of a phenomenon called SASP, the senescence-associated secretory phenotype. Senescent cells are not inert. They actively secrete a cocktail of inflammatory cytokines, chemokines, growth factors, and matrix metalloproteinases. These secreted factors damage neighboring healthy cells, promote chronic low-grade inflammation (sometimes called “inflammaging”), degrade the extracellular matrix, and can even induce senescence in surrounding cells through a bystander effect.

The SASP is what makes senescent cells so destructive. A single senescent cell can corrupt the local tissue environment, triggering inflammation, fibrosis, and dysfunction in cells that were otherwise healthy. Think of it like a single rotten apple in a barrel: the rot spreads. Multiply that across billions of senescent cells distributed throughout your organs, joints, blood vessels, skin, and brain, and you begin to understand why many researchers now consider senescent cell accumulation to be one of the root causes of age-related disease, not merely a symptom of it.

The diseases and conditions linked to senescent cell accumulation are extensive: osteoarthritis, atherosclerosis, idiopathic pulmonary fibrosis, type 2 diabetes, Alzheimer's disease, sarcopenia (age-related muscle loss), kidney fibrosis, liver dysfunction, skin aging, and frailty. In animal models, removing senescent cells has shown improvements in nearly all of these conditions. The question that drives the entire senolytic field is straightforward: if senescent cells are driving these diseases, what happens when you remove them?

What are senolytics?

Senolytics are drugs or compounds that selectively kill senescent cells while leaving healthy, functioning cells intact. The term was coined in 2015 by James Kirkland, MD, PhD, and Tamar Tchkonia, PhD, at the Mayo Clinic. It derives from the Latin “senex” (old) and the Greek “lytic” (destroying). The concept is elegant in its simplicity: if senescent cells are driving aging and age-related disease, and if the immune system can no longer clear them effectively, then a pharmacological intervention that selectively eliminates them should reverse at least some aspects of aging.

The key word is “selectively.” Senescent cells differ from healthy cells in specific ways that can be exploited therapeutically. They upregulate anti-apoptotic pathways, essentially pro-survival programs that prevent them from undergoing normal cell death. These are called SCAPs (senescent cell anti-apoptotic pathways), and they include pathways mediated by BCL-2 family proteins, PI3K/AKT signaling, p53/p21, HIF-1 alpha, and others. Senescent cells depend on these pathways to survive. Healthy cells do not depend on them to the same degree. This creates a therapeutic window: drugs that inhibit SCAPs can push senescent cells past their survival threshold and into apoptosis while leaving healthy cells largely unaffected.

The initial discovery was stunning. Kirkland and Tchkonia demonstrated in their landmark 2015 paper in Aging Cell that a combination of dasatinib (a cancer drug) and quercetin (a plant flavonoid) could selectively clear senescent cells in mice. The results were dramatic. Treated mice showed improved cardiovascular function, better exercise capacity, reduced organ fibrosis, and extended healthspan. Subsequent studies from multiple laboratories showed lifespan extensions of 20 to 36 percent in certain mouse models, along with restoration of physical function, regrowth of fur, improved kidney and liver function, and reduced frailty.

The implications were profound. For the first time, researchers had demonstrated that you could intervene directly in one of the fundamental mechanisms of aging and achieve measurable, visible reversal. Not slowing. Not prevention. Reversal. Old mice were becoming functionally younger. This was not a marginal supplement effect. This was a paradigm shift in how we think about aging as a treatable condition.

It is important to note that senolytics are not taken daily like a typical medication or supplement. Because senescent cells do not return quickly after being cleared, senolytic protocols are typically intermittent. A common research protocol involves taking the senolytic for 2 to 3 consecutive days, then nothing for several weeks. This “hit and run” approach is fundamentally different from the chronic daily dosing model of most pharmaceuticals, and it may significantly reduce the risk of side effects and off-target toxicity.

The research

The senolytic field has produced a substantial body of preclinical research and a growing, though still early, set of human clinical data. Being honest about the state of the evidence is essential for making informed decisions about this class of interventions.

Animal studies

The preclinical evidence for senolytics is, by aging research standards, exceptionally strong. Multiple laboratories using different senolytic compounds in different mouse models have demonstrated consistent and often dramatic benefits.

Dasatinib + quercetin (D+Q) is the most extensively studied senolytic combination. In aged mice, D+Q treatment has shown improved cardiac function with increased ejection fraction and reduced arterial stiffness. Exercise capacity improved, with treated mice running significantly farther and faster on treadmill tests. Organ fibrosis was reduced in the kidneys, liver, and lungs. Bone density improved. Insulin sensitivity was restored toward youthful levels. Most notably, healthspan, the period of life free from major disability, was extended substantially, and overall lifespan increased by approximately 36 percent in transplantation studies where senescent cells were cleared.

Fisetin, a natural flavonoid found in strawberries, apples, and persimmons, has emerged as a promising senolytic in its own right. A 2018 study published in EBioMedicine by the Kirkland laboratory screened 10 flavonoids and identified fisetin as the most potent senolytic among them. In aged mice, fisetin treatment reduced senescent cell markers, lowered SASP-related inflammatory cytokines, and extended median lifespan. The appeal of fisetin lies partly in its accessibility: it is a naturally occurring compound available as an over-the-counter supplement, and its safety profile in human consumption is well-established at moderate doses.

Navitoclax (ABT-263) is a BCL-2 family inhibitor originally developed as an anticancer agent. It is a potent senolytic, effectively clearing senescent cells across multiple tissue types. However, its clinical utility for anti-aging purposes is severely limited by its toxicity profile. Navitoclax causes thrombocytopenia, a dangerous reduction in platelet count that increases bleeding risk. This makes it unsuitable for use in otherwise healthy individuals seeking longevity benefits, though it continues to be studied in cancer contexts where the risk-benefit calculus is different.

Other preclinical senolytics include ABT-737 (another BCL-2 inhibitor), FOXO4-DRI (a peptide that disrupts the interaction between FOXO4 and p53 in senescent cells), and various galactose-conjugated prodrugs that exploit the elevated beta-galactosidase activity in senescent cells to deliver cytotoxic agents selectively. Each of these represents a different mechanistic approach to the same goal: selective elimination of senescent cells.

Human trials

Human clinical data for senolytics is still in early stages, and intellectual honesty requires acknowledging both the promising signals and the significant limitations.

The most prominent early trial was UNITY Biotechnology's UBX0101 study for osteoarthritis. UBX0101 is a small-molecule MDM2 inhibitor designed to clear senescent cells in joint tissue. The Phase 2 trial, which involved intra-articular injection into knee joints of patients with osteoarthritis, produced disappointing results: the drug did not achieve statistically significant improvement in pain scores compared to placebo. UNITY's stock dropped dramatically, and the program was deprioritized. It is worth noting that this result does not invalidate the senolytic hypothesis. It may reflect limitations of the specific compound, the delivery method, the endpoint selection, or the patient population. Osteoarthritis is a complex disease, and a single intra-articular injection may not adequately address the systemic senescent cell burden.

More encouraging early data has come from Kirkland's own studies of D+Q in idiopathic pulmonary fibrosis (IPF), a devastating lung disease with limited treatment options. A small open-label pilot study showed that D+Q was well-tolerated and that patients demonstrated improved physical function as measured by the 6-minute walk test and chair-stand tests. Senescent cell markers in blood decreased. These results are preliminary, involving a small sample without a control group, but they represent the first direct evidence that senolytics can clear senescent cells and improve physical function in humans.

Fisetin trials are ongoing at Mayo Clinic and other institutions. The AFFIRM-LITE trial is evaluating fisetin in older adults, and additional trials are examining fisetin in the context of frailty, chronic kidney disease, and COVID-19 recovery. Results from these trials will be critical in determining whether the dramatic preclinical results translate to meaningful human benefits.

The honest assessment: the preclinical data is compelling and consistent across multiple models and laboratories. The human data is promising but very early. No senolytic drug has been approved by the FDA for any indication. We are in the early innings of clinical translation, and the history of medicine teaches us that many promising preclinical results do not survive the transition to human trials. Cautious optimism is warranted. Premature certainty is not.

What we know and don't know

Clarity about the boundaries of current knowledge is essential in a field this early. Here is a straightforward accounting.

What we know: Senescent cells accumulate with age. This accumulation is not harmless; it drives chronic inflammation, tissue dysfunction, and contributes to multiple age-related diseases. Removing senescent cells in mice consistently improves healthspan and extends lifespan. Several compounds can selectively kill senescent cells in preclinical models. D+Q appears safe and tolerable in small human studies. Fisetin has an established safety profile as a dietary compound.

What we don't know: The optimal dosing protocol for senolytics in humans. How frequently senolytic courses should be repeated. Whether the dramatic mouse results will translate proportionally to humans (mouse-to-human translation has a high failure rate across all therapeutic areas). The long-term safety of repeated senolytic administration over years or decades. Whether senescent cells in some contexts are beneficial and whether removing them could have unintended consequences (for example, senescent cells play roles in wound healing and tumor suppression). Which senolytic is best for which tissue type. Whether over-the-counter supplements like fisetin and quercetin achieve senolytic concentrations in human tissues at commonly used doses.

That last point deserves emphasis. The doses used in successful animal studies, when scaled to human equivalent doses, are often significantly higher than what standard supplement capsules provide. Whether a 100mg fisetin capsule achieves the tissue concentrations needed for senolytic activity is genuinely unknown. The Mayo Clinic fisetin trials use approximately 20mg/kg (roughly 1,400mg for a 70kg person) for 2 consecutive days, a dose substantially higher than typical supplement use.

Senolytic compounds

Several compounds have demonstrated senolytic activity in research settings. They differ significantly in their mechanisms, potency, accessibility, and risk profiles. Understanding these differences is critical for anyone considering senolytic interventions.

Dasatinib + Quercetin (D+Q)

The D+Q combination is the gold standard in senolytic research. Dasatinib is a prescription tyrosine kinase inhibitor approved by the FDA for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia. It targets the SRC family kinases and other tyrosine kinases that senescent cells rely on for survival. Quercetin is a widely available plant flavonoid found in onions, apples, berries, and green tea. It inhibits PI3K, serpins, and other anti-apoptotic targets in senescent cells.

The genius of the D+Q combination lies in its complementary mechanism. Different types of senescent cells depend on different survival pathways. Dasatinib is more effective against senescent human preadipocytes (fat cell precursors), while quercetin is more effective against senescent human endothelial cells. Together, they cover a broader range of senescent cell types than either compound alone.

The research protocol that has been most extensively studied uses dasatinib at 100mg plus quercetin at 1,000mg (1g), taken orally for 3 consecutive days, followed by no treatment for 2 to 4 weeks before the next cycle. This intermittent “hit and run” protocol is designed to exploit the fact that once senescent cells are eliminated, they do not return rapidly. There is no need for daily dosing, which reduces exposure and potential side effects.

Critical caveat: dasatinib is a prescription medication with real side effects. These include fluid retention, pleural effusions, myelosuppression (reduced blood cell production), liver enzyme elevations, and potential cardiac toxicity including QT prolongation. In cancer patients taking dasatinib daily at higher doses, these effects are well-documented. Whether intermittent dosing at 100mg for 3 days produces meaningful toxicity is not yet well-characterized in large studies. This is not something to self-prescribe. If you are considering D+Q, you need a physician who understands both the senolytic research and the pharmacology of dasatinib.

Fisetin

Fisetin is the senolytic compound generating the most excitement in the longevity community, primarily because of its accessibility and safety profile. It is a naturally occurring flavonoid found in highest concentrations in strawberries (approximately 160 micrograms per gram), though the amounts in whole foods are far below therapeutic senolytic doses.

The Mayo Clinic is studying fisetin at doses of approximately 20mg/kg of body weight for 2 consecutive days per month. For a 70kg (154-pound) person, that translates to roughly 1,400mg per day for 2 days. This is a significantly higher dose than the 100 to 500mg daily that most supplement protocols recommend, and it is designed as an intermittent protocol, not a daily supplement regimen.

Fisetin's senolytic mechanism involves inhibition of PI3K/AKT/mTOR pathways and modulation of BCL-2 family proteins. It has also demonstrated anti-inflammatory, antioxidant, and neuroprotective properties independent of its senolytic effects, which may provide additional benefits even if senolytic tissue concentrations are not fully achieved.

The evidence for fisetin is earlier stage than D+Q. The landmark mouse study showed lifespan extension, but it was a single study. Human trials are ongoing but results are not yet published in peer-reviewed form. The bioavailability of oral fisetin is relatively low (estimated at roughly 44% in animal studies), which raises questions about whether oral dosing achieves sufficient tissue concentrations for senolytic activity.

That said, fisetin is generally well-tolerated, available without a prescription, and affordable. For individuals who want to explore senolytic interventions with minimal risk, fisetin taken in a high-dose intermittent protocol represents perhaps the most pragmatic entry point while we wait for more definitive clinical data.

Quercetin alone

Quercetin is one of the most studied flavonoids in nutrition science and has well-documented anti-inflammatory and antioxidant properties. As a senolytic, however, quercetin alone is significantly weaker than the D+Q combination. The original Kirkland research demonstrated that quercetin's senolytic effect is cell-type-specific: it is effective against senescent endothelial cells but less so against other senescent cell types. The synergy with dasatinib is what gives D+Q its broad senolytic coverage.

Quercetin is widely available as an OTC supplement, typically in doses of 500 to 1,000mg. It has a strong safety record at these doses. Whether quercetin alone at supplement doses achieves meaningful senolytic clearance in humans is unproven. It likely provides anti-inflammatory and antioxidant benefits regardless, but claiming robust senolytic effects from quercetin supplementation alone would be getting ahead of the evidence. The research supports the combination, not the single agent at typical supplement doses.

Other compounds

The senolytic pipeline extends beyond D+Q and fisetin, though most compounds are either too toxic for anti-aging use or too experimental for human application.

Navitoclax (ABT-263) is a potent BCL-2/BCL-xL inhibitor that effectively clears senescent cells across multiple tissue types. Its senolytic potency is arguably the highest of any compound studied. However, BCL-xL inhibition causes dose-dependent thrombocytopenia (dangerously low platelet counts), making it unsuitable for use in healthy individuals. Modified versions (such as BCL-2-selective inhibitors or platelet-sparing formulations) are in development, but none are available for clinical use in anti-aging contexts.

FOXO4-DRI is a cell-penetrating peptide that disrupts the interaction between FOXO4 and p53 in senescent cells. In healthy cells, p53 triggers apoptosis when activated. In senescent cells, FOXO4 sequesters p53 in the nucleus, preventing apoptosis. FOXO4-DRI blocks this interaction, freeing p53 to induce apoptosis specifically in senescent cells. In mice, FOXO4-DRI reversed age-related fur loss, improved kidney function, and increased physical activity. The compound is experimental, not commercially available, and has not entered human clinical trials.

Galactose-conjugated prodrugs represent an innovative targeting strategy. Senescent cells express high levels of senescence-associated beta-galactosidase (SA-beta-gal), an enzyme that can cleave galactose sugar groups. By attaching a galactose molecule to a cytotoxic drug, researchers can create a prodrug that is inactive until it encounters a senescent cell, where SA-beta-gal cleaves the galactose group and releases the active drug locally. This approach offers potentially superior selectivity but remains in preclinical development.

Should you take senolytics now?

This is the question everyone who reads about senolytics eventually asks, and the honest answer depends heavily on your individual context, risk tolerance, and access to qualified medical supervision.

If you are under 40 with no chronic conditions: probably premature. Your immune system is still relatively effective at clearing senescent cells. Your senescent cell burden, while not zero, is likely low enough that the risk-benefit ratio of pharmacological intervention does not clearly favor action. The most impactful things you can do for longevity at this stage are well-established: consistent exercise (which itself has senolytic properties through autophagy and cellular cleanup mechanisms), adequate sleep, stress management, and avoiding metabolic dysfunction. These interventions have decades of human evidence behind them. Senolytics do not, yet.

If you are 50 or older, or show signs of accelerated biological aging: the calculus changes meaningfully. Your senescent cell burden is higher. Your immune surveillance is less efficient. The conditions driven by senescent cell accumulation (joint degeneration, cardiovascular stiffness, cognitive decline, reduced physical resilience) may already be affecting your quality of life. In this context, some longevity physicians are prescribing D+Q protocols off-label, typically 3 days on followed by 3 to 4 weeks off, with monitoring of blood counts, liver function, and clinical response. A growing number of informed adults in this demographic are experimenting with high-dose intermittent fisetin protocols as a lower-risk alternative.

The practical middle ground for most people: fisetin as a high-dose intermittent protocol (approximately 1,000 to 1,500mg per day for 2 consecutive days per month) represents the lowest-risk senolytic intervention currently available. The compound is well-tolerated, available over the counter, and being studied at these doses in clinical trials. It may or may not achieve full senolytic clearance at oral doses, but the risk of harm is low and the potential for benefit, even if partial, is real.

What you should not do: order dasatinib online without medical supervision, follow dosing protocols from forums or blog posts without understanding the pharmacology, or assume that because something works dramatically in mice it will work identically in you. This is frontier medicine. The research trajectory is exciting. But frontier medicine requires frontier-level medical supervision, not self-experimentation guided by YouTube videos.

If you are serious about incorporating senolytics into a broader longevity strategy, find a physician who reads the primary literature, understands the pharmacology, can monitor you appropriately, and is willing to have an honest conversation about what is known and what is not. Senolytics work best as one component of a comprehensive approach that includes NAD+ optimization, autophagy-promoting practices, peptide therapies where appropriate, exercise, sleep optimization, and metabolic health management.

Senolytics vs other longevity interventions

Senolytics do not exist in a vacuum. They are one tool in a growing arsenal of longevity interventions, each with a different evidence base, risk profile, and mechanism of action. Understanding how senolytics compare to other options is essential for building a rational longevity strategy.

A few observations from this comparison. Exercise remains the single most evidence-supported longevity intervention available. It is free, has minimal risk, and operates through multiple mechanisms simultaneously including senescent cell clearance (exercise induces apoptosis in some senescent cells), mitochondrial biogenesis, improved insulin sensitivity, reduced inflammation, and enhanced immune surveillance. If you are considering senolytics but do not exercise regularly, address that first. The evidence base is incomparably stronger.

Senolytics and NAD+ therapy address different mechanisms of aging and may be complementary. Senolytics clear the damaged cells that secrete inflammatory factors. NAD+ optimization provides the cellular fuel needed for DNA repair, mitochondrial function, and sirtuin activity. Combining these approaches makes mechanistic sense, though clinical data on combination protocols in humans is essentially nonexistent at this point.

Autophagy-promoting interventions like intermittent fasting and caloric restriction share some functional overlap with senolytics. Autophagy clears damaged cellular components and can contribute to the elimination of some senescent cells. However, the mechanisms are not identical, and senolytics likely achieve a degree of senescent cell clearance that autophagy alone cannot match, particularly in heavily burdened tissues.

The future of senolytics

The senolytic field is evolving rapidly, and the next generation of interventions may look very different from the current D+Q and fisetin protocols.

Targeted senolytics are perhaps the most exciting frontier. Rather than using systemically delivered drugs that affect all tissues, researchers are developing senolytics that clear senescent cells in specific organs or tissue types. Galactose-conjugated prodrugs, discussed earlier, represent one approach. Another is the development of senolytic CAR-T cells, chimeric antigen receptor T cells that are engineered to recognize and destroy senescent cells expressing specific surface markers like uPAR (urokinase plasminogen activator receptor). A 2020 study in Nature demonstrated that uPAR-targeting CAR-T cells could selectively eliminate senescent cells in mice, improving liver fibrosis and metabolic function. This is essentially immunotherapy for aging, applying the same principles used in cutting-edge cancer treatment to the problem of cellular senescence.

Gene therapy approaches represent another long-term possibility. If the genes responsible for senescent cell survival (the SCAPs) can be selectively silenced or disrupted using gene editing tools like CRISPR, it might be possible to create highly selective, long-lasting senolytic effects without repeated drug dosing. This remains firmly in the research phase, but the pace of gene therapy development suggests it could become clinically relevant within the next decade.

Combination protocols that integrate senolytics with other longevity interventions are likely to become the standard of care in longevity medicine. Imagine a protocol that combines periodic senolytic clearance with NAD+ replenishment, mTOR modulation through rapamycin or its analogues, targeted peptide therapies for tissue repair and regeneration, and optimized exercise, sleep, and nutrition protocols. Each intervention addresses a different hallmark of aging, and together they could produce synergistic effects far greater than any single approach alone.

Senomorphics, compounds that suppress the SASP without killing senescent cells, offer an alternative or complementary approach. Rather than eliminating senescent cells entirely, senomorphics aim to neutralize their harmful secretions while preserving any beneficial functions. Rapamycin, metformin, and certain JAK inhibitors have demonstrated senomorphic properties. The eventual optimal protocol may involve both senolytics (periodic clearance) and senomorphics (continuous SASP suppression) used in combination.

The field is moving fast. What is experimental today may be standard of care in 5 to 10 years. The key investments you can make now are maintaining your baseline health through proven interventions, staying informed about the research as it develops, and establishing relationships with physicians who operate at the frontier of longevity medicine rather than waiting until these therapies reach mainstream adoption years later.

Frequently asked questions

Are senolytics FDA approved?

No. As of April 2026, no drug has been approved by the FDA specifically as a senolytic for any indication. Dasatinib is FDA-approved for certain leukemias, and its use in senolytic protocols is off-label. Quercetin and fisetin are available as dietary supplements and are not regulated as drugs by the FDA. Several senolytic drugs are in clinical trials, but none have completed the approval process for anti-aging or senolytic indications. The TAME (Targeting Aging with Metformin) trial, while focused on metformin rather than senolytics specifically, may help establish regulatory precedent for aging as a treatable condition, which would benefit the senolytic field broadly.

Can I buy senolytics?

Quercetin and fisetin are available over the counter as dietary supplements from numerous retailers and supplement companies. These can be purchased without a prescription. Dasatinib requires a prescription and is typically prescribed off-label by longevity-focused physicians who understand the research. Do not attempt to purchase dasatinib from unregulated online sources. The quality control, dosing accuracy, and purity of gray-market pharmaceuticals are unreliable, and you would be taking a prescription medication without appropriate medical monitoring. If you want D+Q, find a physician who will prescribe it appropriately and monitor your bloodwork.

How often should you take senolytics?

Senolytic protocols are intermittent, not daily. The most commonly studied protocol for D+Q involves 3 consecutive days of treatment followed by a rest period of 2 to 4 weeks before the next cycle. For fisetin, the emerging research protocol is 2 consecutive days per month at approximately 20mg/kg body weight. The intermittent dosing reflects the biology: once senescent cells are cleared, they do not return quickly, so there is no need for continuous dosing. The optimal frequency in humans has not been definitively established, and it likely varies based on age, health status, and senescent cell burden. Work with a knowledgeable physician to determine the protocol that makes sense for your situation.

Are senolytics safe?

The safety profile depends on the specific compound. Fisetin and quercetin have strong safety records as dietary supplements at typical doses, with minimal reported adverse effects. Whether they are safe at the higher doses used in senolytic protocols over extended periods is still being evaluated in clinical trials. Dasatinib has known side effects including fluid retention, myelosuppression, and potential cardiac effects, though these are primarily documented in cancer patients taking the drug daily at higher doses and for longer durations than senolytic protocols require. The intermittent, short-duration dosing used in senolytic research may significantly reduce these risks, but long-term safety data for this specific use pattern does not yet exist. The general principle: lower-risk options (fisetin) exist, higher-potency options (D+Q) require medical supervision, and self-experimentation without monitoring is inadvisable regardless of the compound.

What is the difference between senolytics and senomorphics?

Senolytics kill senescent cells. Senomorphics modify the behavior of senescent cells without killing them, primarily by suppressing the SASP (the inflammatory secretions that cause most of the damage). Think of it this way: senolytics remove the zombie cells entirely, while senomorphics keep the zombie cells alive but prevent them from spreading their toxic influence to neighboring cells. Both approaches aim to reduce the damage caused by cellular senescence, but through fundamentally different mechanisms. Rapamycin and metformin have demonstrated senomorphic properties. The eventual optimal protocol may combine both: periodic senolytic clearance to reduce the senescent cell population, plus continuous senomorphic suppression to neutralize the SASP from any remaining senescent cells. Research on combination approaches is early but conceptually compelling.