Brian Johnson explains that 90% of your cells replace every 90 days, giving you a biological reset each quarter. He treats personal development like an experiment: measure biomarkers with blood work, adjust habits, review results. Progress isn't linear, but each cycle lets you step into a better version of yourself.
It doesn't matter your age. Every 90 days, 90% of your trillions of cells are new. There's a new you. 90% of you is new every 90 days. That's incredibly inspiring. And that means that we have the opportunity, growth mindset, Optimized Mindset style, to fuel ourselves as optimally as we can and create a new version of ourselves every 90 days. To me, that's exhilarating, and you can see it. I do my blood work basically every 90 days or so, And you see it. I mean, you can move the needle on whatever thing you want to optimize, just change a little bit, get the data, 90 days later, go check it again and boom, you've moved it. Oh, what can we do now? Boom, move it. And sometimes you're gonna take 3 steps forward, and then you're gonna slide back a step or 2, which is what I did in my recent experimentation, whatever, dust yourself off, it's all data, use that to get a little bit better the next time. But the point here is, we're always reinventing ourselves at a cellular level, We can choose to step forward into the next best version of ourselves.
