Fisetin inhibits PI3K/AKT/mTOR signaling — the same pathway targeted by rapamycin (the most robust life-extension compound in animal models). This results in autophagy induction, reduced protein synthesis, and cell cycle arrest. Unlike rapamycin, fisetin is non-immunosuppressive at supplement doses, making it suitable for long-term use without infection risk.

Should I take fisetin with or without food for mTOR inhibition?

Ironically, food (especially protein and carbohydrates) activates mTOR, potentially blunting fisetin's mTOR-inhibitory effects taken simultaneously. For maximal mTOR inhibition, taking fisetin in a fasted or ketogenic state may be preferred. For senolytic activity, however, fat co-administration improves absorption — a trade-off to consider.

Is fisetin a substitute for rapamycin?

No. Fisetin is a mild mTOR modulator; rapamycin is a potent, specific mTOR inhibitor with strong lifespan extension data. Fisetin adds senolytic activity rapamycin lacks, making them complementary rather than interchangeable.