Does fisetin from strawberries really work as a zombie-cell clearer?
Fisetin demonstrably clears zombie cells in cell experiments and in animals, but whether this also works in people and is safe has not yet been established. Do not take it as a supplement for now outside ongoing studies in people.
Fisetin is found in strawberries, but also in apples and onions. In experiments with cells and tissue, it turned out to be the most powerful 'senolytic' among nine plant compounds tested. Senolytics are substances that selectively clear out aged, worn-out cells (also known as zombie cells). This is promising, but the work involves cells and tissue, not studies in people.
In mice, the results are remarkably consistent. Old mice that received fisetin late in life lived longer on average and were healthier. An alternating schedule of one week of fisetin, two weeks off, one week of fisetin reduced arterial stiffness and improved blood vessel function. Mouse results do not automatically carry over to people, however.
In people, the research is still at a very early stage. Small pilot studies with zombie-cell clearers, including fisetin, show positive signals: fewer zombie cells, lower inflammation markers, and fewer signs of frailty in older adults. Firm conclusions about safety, dosing, and effectiveness are not yet available. The researchers state explicitly that use outside controlled studies is premature for now.
There are also safety questions. Zombie-cell clearers as a group have been linked to low platelet counts. The optimal dose of fisetin is unknown and side effects in people have not been studied sufficiently. There is also early animal research into fisetin in the context of serious infections, but evidence in people is entirely lacking there.
Sources used: mouse and tissue studies on fisetin as a zombie-cell clearer, mouse studies on arterial function, blood proteins, and infection, early pilot studies in people, an overview of the status of fisetin studies in people, and a source on dosing and side effects of zombie-cell clearers. No combined analyses of many studies were used as a direct source.
What do zombie cells do to your ageing?
Zombie cells accumulate as you age and accelerate ageing through inflammatory signals; how to tackle them is promising but still very much under investigation.
Can fasting really rejuvenate your cells?
Animal studies show convincing signs of cellular rejuvenation through fasting, and the first studies in people point in the same direction.
Does chronic inflammation accelerate the ageing of your cells?
Chronic inflammation demonstrably accelerates cellular ageing through a negative spiral that is difficult to break. The best evidence-based approach to tackling that spiral is through lifestyle factors that dampen low-grade inflammation, such as sufficient exercise and a diet low in ultra-processed products.
Does the protein GDF11 rejuvenate old cells?
GDF11 rejuvenates certain tissues in mice, particularly the heart, but whether this works in humans has not yet been investigated. There is no basis for acting on this now.
What does caffeine do to your cells and their repair process?
Animal studies show that caffeine affects cells in different ways depending on the situation. Until comparable studies in people are available, it remains unclear what this means in practice for everyday use.
Do sirtuins actually do anything against ageing?
Sirtuins play a clear role in ageing in animal research, but whether they are of any benefit to humans (through supplements or other means) remains unknown. Wait for human evidence before acting on any sirtuin-based claims.