I've been experimenting with taking NMN and NR together for the past six months and honestly the synergistic effect on my NAD+ levels has been incredible compared to when I was just using NMN vs NR individually, the combination seems to hit both the Slc12a8 transporter pathway for NMN absorption and the NRK1 NRK2 enzymes for NR conversion which makes total sense from a NAD+ biosynthesis perspective since you're essentially feeding both the salvage pathway and Preiss-Handler pathway simultaneously to boost NAD+ naturally, I take 500mg NMN with 300mg NR every morning on an empty stomach about 30 minutes before my HIIT workout and the energy boost plus improved muscle recovery has been noticeable especially at my age where NAD+ decline with age really starts hitting hard, plus I stack it with quercetin as a CD38 enzyme inhibitor and TMG for methylation support which seems to help with NAD+ preservation, my sleep quality improved dramatically within the first month which makes sense given how NAD+ affects circadian rhythm regulation, and while NMN clinical trials and NR clinical trials show benefits for each individually I'm convinced this NMN NR combination approach maximizes cellular repair supplements energy production and mitochondrial function better than either nicotinamide mononucleotide or nicotinamide riboside alone, no side effects so far and my insulin sensitivity seems better too which aligns with the metabolic health research on these NAD+ precursors.