Is this the kind of thing one can easily buy? Do we know how she it is for general use?
Vitamin B3 also increases NMN level and is a precursor to NMN. It's probably better to just take nicacin (B3) as its safer until NMN is proven to be safe for human in longer doses. NMN is too large molecule to enter cells so anyway its broken down before it can be absorbed.
Edit: found at least one study since then, written about here. https://www.lifespan.io/news/niacin-increases-nad-significan...
B3 is a precursor to NAD+ but you also need some amino acids to make it.
Taking NMN directly also had some health issues that were discovered recently. More importantly it can speed up cancer if you are predisposed to it or if you already have undiagnosed cancer.
as far as I can remember, one of the treatments of cancer is removing nmn from body.