I've been meaning to start donating blood and/or plasma for a few years now, partly because it's a good thing to do, but also as a way to shed accumulating substances (PFASs have been studied, but also background heavy metals in the case of whole blood donation), but I use topical finasteride for hair loss, which I'd have to stop for a month before donating.

So, say I took a month off from finasteride, and then spent a month donating: whole blood once, and plasma 7 times. If my math is right, I'd have donated / regenerated 1 - 0.92^8 = ~half my blood volume; and ~10% of my body weight. Then maybe back to finasteride for two months, another month of no finasteride, and another donation month?