My magic threshold appears to be less than 500mg!!
So when I started taking NMN almost 11 months ago it was accompanied by a whole load of lifestyle changes and a large addition to the supplements I was taking (had only previously been supplementing Vitamin D as a blood test had shown a clear deficiency). The thing was, once the changes had been made, I found that I was having to get up in the middle of the night to go to the toilet (which previously I hadn't had to do). The other obvious thing I noticed was that a Sunday night, after a day or two of no supplements, I didn't have to get out of bed.
Therefore, in the last 11 months I've been making all manor of adjustments, whilst keeping all other things constant to see what might have been causing the problem as it could have been any one of the supplements, the timings when taken or the fasting regime.
And now I finally have the answer - it is the NMN. Up to 375mg (or thereabouts) of NMN is fine, and I feel absolutely no need to go to the toilet at night time, but as soon as I go for 500mg or above, the side effect starts again. (Any amount of any other supplement makes no difference, likewise, it makes no difference if the NMN is taken at different times or spread through the day or taken in one go.
So, I wonder, if anyone else has noticed this side effect, and what causes it?
Maybe 375mg, which I take sub-lingually, gives me the exact amount I need (52 years old and somewhere between 75 and 80Kg in weight) and anything above this is too much which the body is trying to wash away.
(I suspect 375mg taken sublingually is absorbing much more than 1g swallowed in a capsule).
For those thinking of upping their dosage, maybe this side effect is an indicator of where your "magic threshold" happens to be.