Senolytics in 2026: Dasatinib plus Quercetin, Fisetin, and What Human Trials Have Shown

Do senolytics work in humans?

Senolytics are drugs meant to kill worn-out (senescent) cells. These are damaged cells that stop dividing but keep sending out inflammation signals. Nobody has shown this works in people yet. In mice, clearing these cells improves how the body works and lengthens life in several kinds of experiments. The human story is smaller, slower and more honest than the ads around it. This article walks through every result in people, with its size and length, so you can see the gap between what is sold and what is known. Dasatinib is an FDA-approved leukemia drug used off-label in these studies. Quercetin and fisetin are supplements with no drug approval. Foselutoclax and RLS-1496 are still being tested and can't legally be sold.

Where are the fisetin trials?

Fisetin became the internet's favorite senolytic because you can buy it, and because mouse studies suggested it was the strongest of the natural compounds tested. In people, the record is thin. The only fisetin study with posted results was run by the Steadman Philippon Research Institute in 75 people with knee arthritis, 34 on fisetin and 40 on a dummy pill. It used 100 mg capsules to reach about 20 mg/kg a day for two days in a row, then repeated after 28 days off. Results posted in September 2024 showed no real difference from the dummy pill in inflammation (C-reactive protein), a cartilage marker (COMP), physical function, pain or cartilage on MRI. Safety was no different either (ClinicalTrials.gov NCT04210986). The Mayo studies are the ones the field is waiting on. Their finish date has been pushed to November 2026 (ClinicalTrials.gov NCT03675724).

What is RLS-1496 and what did its first human trial show?

The results on whether it works were early. 25 percent of people with eczema on the cream had a 4-point drop in itch, against none on the empty cream. Skin samples showed collagen genes rising and inflammation markers falling over the month (Rubedo, March 2026). A next-stage study in rough, scaly sun-damaged skin (actinic keratosis) is running in the US. It is a skin cream in early testing, not an anti-aging pill, and you can't get it outside those studies.

What happened to foselutoclax (UBX1325) in the eye?

Foselutoclax is the most carefully tested senolytic in people. It is injected into the eye, where worn-out cells are thought to make blood vessels leak. Unity Biotechnology's study was bold: it compared the drug against the standard eye drug, not a dummy shot. The drug was about as good at 9 of 10 check-ins and cleared the bar at week 36. In a group picked in advance, people whose retinas were thinner at the start did better on it than on aflibercept. But the main test missed. On May 5, 2025, Unity said it was letting go of all its staff, moved its leaders to consulting roles and began looking to sell, license or merge the program (Unity Biotechnology, May 2025). As of September 2026, no partner has been announced.

What did the dasatinib plus quercetin trials show?

Two things stand out. First, the drugs do something you can measure. The Hickson fat-sample data are still the clearest evidence that a senolytic lowers the number of worn-out cells in human tissue (EBioMedicine, 2019). Second, the one study against a dummy pill did not repeat the walking gains of the open test. And the treated group had three times as many minor side effects, with more trouble sleeping and more anxiety (EBioMedicine, 2023). Twelve people can't settle the question either way, and that is the point. After seven years, all the D+Q evidence from people split by chance into groups adds up to 12 people for 3 weeks.

Senolytic supplements versus what the trials actually used

Products sold as 'senolytic activators' or 'senolytic complexes' usually contain fisetin, quercetin or both, sometimes with other plant compounds, in capsules you take every day. Compare that with the studies:

• The one fisetin study with results failed. The high-dose pulse did no better than a dummy pill on pain, function or cartilage in 75 people.
• The fisetin studies used pulses, not daily capsules. AFFIRM-LITE and the knee study gave about 20 mg/kg a day for two days in a row, roughly 1,400 mg a day for a 70 kg adult, then nothing for weeks. The knee study needed about 14 of its 100 mg capsules a day to get there. A daily capsule gives a small slice of that, on a schedule no study has tested.
• Quercetin was never tested alone. In every D+Q study, it was paired with dasatinib, a prescription cancer drug. A quercetin capsule is not half of a senolytic treatment. Quercetin alone has no senolytic data from people.
• Blood tests sold as 'senescence panels' are not proven measures. The studies measured worn-out cell markers in tissue samples and inflammation chemicals in blood as side measures, not as proof of benefit.

The bottom line

Senolytics are one of the best-backed ideas in the biology of aging, and one of the least proven in medicine. D+Q data from people show the drugs reach tissue, but no proper study has shown people function better. Fisetin's main studies are eight years old and unfinished, and its one finished study failed. The best-run senolytic study so far, ASPIRE, missed by a hair, and its company is winding down. RLS-1496 is the newest, with a safety result on skin. If you see a capsule sold as a senolytic in 2026, the honest label is: an ingredient from a study that hasn't reported, at a dose and schedule no study used. More reading: what the FDA changed for peptides in 2026, klotho and the new compounds of 2026.