NAD+ Protocol: Concentrations Behind the Schedule

Read the last column first. It does not move. Twenty portions of 50 mg come out of a 1000 mg vial no matter how much water went in, because the numerator was fixed at the factory and water is not material. Anyone who believes a larger fill volume stretches a vial is confusing volume with mass, and this column is the whole refutation.

What does move is everything about the reading. One unit carries 2 mg at the top of the table and 0.5 mg at the bottom, a factor of four. The same 50 mg portion is a quarter barrel, a half barrel and a whole barrel down the three rows. So the fill volume decision is a precision decision and a capacity decision, and it is nothing at all to do with how much compound is available.

Precision is worth stating as a ratio. At 25 units drawn, misreading by one graduation shifts the mass by one part in twenty five. At 100 units drawn, the same single graduation error is one part in a hundred. Larger fill volumes buy finer relative resolution, and they buy it up to the point where the draw no longer fits in the barrel.

The bottom row of that table is already at the limit. A U-100 insulin syringe holds 1 mL, so a 50 mg portion at 50 mg per mL fills it completely with no margin for a bubble or a slow pull. Anything above 50 mg at that concentration needs two draws or a different syringe.

This constraint never appears on a 5 mg peptide vial, where a typical draw is a tenth of a barrel and the barrel is a comfortable oversupply. At NAD+ masses the barrel becomes the binding limit, and it binds from the direction people do not expect: the dilute preparation is the one that runs out of room, not the concentrated one.

There is a matching constraint at the other end. A 1000 mg vial asked to hold 20 mL of water needs a container that will physically accept 20 mL alongside a gram of solid. Small crimp vials of the sort the rest of this site discusses will not, so the choice of fill volume is often made by the glass rather than by the arithmetic, and it is worth checking the container before planning a concentration around it.

The first is that powder occupies no space. Concentration is normally computed as labelled mass divided by water added, which treats the solid as invisible. Take an assumed solid density of 1.5 g per mL, stated as an assumed input so the arithmetic can run rather than as a measured property of any product. Five hundred milligrams then occupies roughly 0.33 mL, and the distortion depends sharply on how much water it is competing with.

The same solid, the same label, three quite different sized errors. Tight fill volumes amplify the effect, which is inconvenient, because tight fill volumes are exactly what a small vial forces. The fix is not a correction factor but a change of method: if the container carries graduations, reconstitute to a marked final volume so the denominator is read rather than assumed, and the density guess disappears from the calculation.

The second broken assumption is that measuring the diluent is a single clean act. Adding 2 mL with a 3 mL syringe is one transfer. Adding 10 mL with a 1 mL syringe is ten, and each transfer leaves a little behind in the hub and needle. Assume 0.02 mL residual per pass, again as an assumed input: ten passes deliver about 9.8 mL rather than 10, so the concentration lands near 51 mg per mL where 50 was intended. It is a small systematic bias in one direction, and it is removed entirely by using one appropriately sized syringe instead of ten small ones.

The third is that a unit is a fine graduation. At 200 mg per mL it carries 2 mg, which is more compound than several whole vials elsewhere in this catalogue contain. Nothing about the syringe changes; the amount riding on each mark does.

No figure on this page is a recommendation, and none of the arithmetic is run toward one. That is a deliberate stopping point rather than an omission, and the reason is specific to this compound.

The human interventional literature here overwhelmingly tested oral precursors, nicotinamide riboside and nicotinamide mononucleotide, taken by mouth and converted inside the body. Injected NAD+ is a different intervention with a much thinner evidence base, and no regulator anywhere has issued a marketing authorisation for it. There is therefore no established relationship between an injected mass and an outcome in people for the arithmetic to work from.

Division converts between mass, volume and graduations. It has no access to what a mass does. Every number above is a statement about a container, and a container statement cannot be promoted into a health statement by dividing it more carefully.

The obvious repair is to take an oral precursor amount from a human trial and convert. Write the conversion out and it collapses. An equivalent injected mass would be the oral amount multiplied by the fraction absorbed, by the fraction converted onward to NAD+, and by a term relating the two routes. That is three unknowns against one known, and no figure is asserted here for any of the three.

A calculator will still return a value if someone supplies guesses. The tables above are definitional, and division cannot be wrong about a ratio. A precursor conversion is an empirical claim with arithmetic painted on it, and the two kinds of number should never appear in the same column.