Alright I'll start: Absolutely nothing too crazy and don't even know if it qualifies as 'biohacking' but I thought it might be an useful addition. I've been taking 1000mg of Paba supplement pills for a year now to combat a few strand of grey hairs... And it actually helped. Whether it is placebo or not, I have no idea but it is pretty much reversed. There are only a few old studies saying positive things about it's effect. I'll keep taking it.