The problem really began when supplement users discovered that Amazon was selling a lot of fake NMN products and informed Jeff Bezos. They stopped the fakes, but they also blocked the legitimate companies, particularly ChromaDex and DoNotAge. ChromaDex still offers their Tru Niagen (NR) supplement on Amazon which is another NAD precursor like NMN. You can still get NMN directly from DoNotAge regardless of the efforts of the FDA, Metro Biotech, and Amazon.
Frankly, the NMN cost is way too high for most people. Even from the low cost DoNotAge the daily dose is about $1. The lowest cost NAD booster is actually good old Niacin (B3). The body converts Niacin to NMN and the cost for a reasonable 50-100mg dose is under a penny a day.
I couldn’t possibly take ordinary niacin (B3) — that was a one time thing never to be repeated but have settled on liposomal NAD+ with betaine for $0.25/dose. Both betaine and the liposomal characteristic markedly improve absorption.
Many thanks! Check out this man at Twitter. He says niacin taken with glutamine is the magic NMN producer https://twitter.com/NiacinGlutamine
One gram of each taken at the same time. I follow him at Twitter.