I gave only 4 stars because I've only…
I gave only 4 stars because I've only been on NMN for a couple weeks now I do believe it will work over time and I do feel a bit more energetic and I did receive one (unusual) compliment from my brother, he asked me if I had done anything different i.e. hair cut, saved my face ect.. he saw something different in me but could pin point it. So maybe even if I can't completely see the affect my self maybe others can. It's not a miracle pill you won't wake up the day after taking it and look and feel 30 years younger but I do think it will work to improve my vision and over all appearance.