Personally I take Optis NAD+500. I inject in the morning. I want to tell you it is probably very much placebo as a caution. Enough research exist now to confirm NAD isn't readily available even when injected. But that's what they say. Hopefully on the horizon Opti will move towards MOTSc.
With that said I inject 500mg in the a.m. IM. I feel it immediately with a slight head rush, and some minor sinus blockage. This apparently is extremely common and in fact proves it is working. I say this so that you can make an informed decision to try it. I don't drink coffee or have other stimulants in my system, but like most I'm groggy at times on certain days. NAD seems to kick that, and I'm hyper alert, and focused. I get shit done. Haha
So placebo, or in actuality I just can't be sure, but consistently I get a head rush, not really euphoric, but just a quick blast and I'm off. I like it, so if the science is right... Mind over matter I guess. N going to keep it up.