Senolytics

In people, the trials are small and early. In 14 people with idiopathic pulmonary fibrosis, three weeks of intermittent dasatinib plus quercetin improved walking and chair-stand tests, with no placebo group [1]. In nine people with diabetic kidney disease, a three-day course lowered markers of senescent cells in fat tissue [2]. In five people with early Alzheimer's disease, dasatinib reached the spinal fluid and the treatment was tolerated, with no change in memory tests [3].

The largest randomized trial so far missed its main goal. In 60 postmenopausal women, intermittent dasatinib plus quercetin did not reduce bone breakdown at 20 weeks, though bone formation rose briefly and women with the most senescent cells seemed to respond more [4].

The strong results are in mice. Dasatinib plus quercetin improved physical function in old mice and raised survival after treatment [5], and fisetin given late in life extended median and maximum lifespan [6]. In the Interventions Testing Program, fisetin did not extend lifespan in genetically mixed mice at the dose and schedule tested [7]. Dasatinib is approved only to treat certain leukemias, fisetin and quercetin are sold as supplements, and no senolytic is approved to treat aging.

• Dasatinib is a prescription cancer drug. Using it to slow aging is off-label and unproven, and it belongs only under a physician's care.
• In a pilot trial, side effects included breathing symptoms, skin irritation or bruising and stomach upset [@justice2019]. At cancer doses, dasatinib can also lower blood counts and cause fluid to build up around the lungs.
• Senescent cells help with wound healing, so clearing them around surgery, injury or pregnancy may not be harmless.
• Fisetin and quercetin supplements are not checked by the FDA for purity or dose, and study doses are far above what food provides.
• No senolytic is approved to treat aging, and long-term effects in healthy people are unknown.