How do you know you have this? I got so much benefit from Nicotinamide Riboside, and after years of low vitamin D levels finally found one supplement that raised them, VeganD3+K2 - I’m not vegan but that is the one that has worked. Not sun (I get plenty of that) nor fish nor any other supplement ever got it out of the alleged critically low range.
I lost one, sent the emails I might need to another account. So that was ok but I forgot to change the email on every freaking service I use so it was very difficult to recover some accounts.