NAD+ IV versus oral versus patches, which actually gets absorbed?

Short answer, they're all leaky buckets in different places. IV gets NAD+ into your blood at basically 100 percent, that part's not in dispute. But there was a small pilot study that showed urinary NAD+ spiking over 500 percent during a six hour infusion, which means a big chunk of what they're charging you for is going straight into your bladder, not your cells. NAD+ is also a fairly large charged molecule, it doesn't just diffuse across a cell membrane, so even what stays in your blood has to fight to get where you actually want it.

This tracks with what I see on the floor honestly, big IV pushes of anything don't mean the tissue is soaking it up, kidneys just do their job and dump the excess. Doesn't mean the drip does nothing, just means you're not getting a 1 to 1 return on what's infused.

I tried tracking this for myself for about 8 weeks. Oral NMN, sublingual NR, and one IV session thrown in for comparison. My subjective energy scores (1-10, logged daily) were basically flat across all three, no discernible bump around dosing days versus non dosing days. n=1 and I'm not blinded so take it for what it's worth, but I expected at least a placebo blip and didn't even get that.

From the pharmacy side, oral NAD+ itself (not precursors) is a rough sell, stomach acid and gut enzymes chew through most of it before it ever reaches the bloodstream, estimates run somewhere in the single digit to low teens percent bioavailability. That's part of why the precursor argument (NMN, NR) makes sense mechanistically, smaller molecules, cells can actually take them up and build NAD+ internally instead of you trying to force the finished molecule across a gut wall.

This is the same conversation I have with lifters about creatine loading protocols, everyone wants the fancy delivery system before they've nailed the boring basics. Sleep, protein, actual training stress. NAD+ pathway stuff is interesting but it's the last five percent for most people chasing tendon recovery, not the first move.

Fair, I'm not skipping sleep for this, just trying to figure out if the drip money is better spent elsewhere. Sounds like the answer might be yes.