NAC Reconstitution Calculator
NAC (N-Acetylcysteine) is listed in the Antioxidant category of The Longevity Archive, with a half-life of ~5-6 hours (about 5.5 hr). Enter what is on the NAC vial label, the bacteriostatic water you add, and the amount per draw you were given. You get the units on a 0.3, 0.5 or 1 mL insulin syringe snapped to a real mark, the mixing steps, draws per vial and a printable label. The tool converts a number you already have; it never sets one. Read the NAC research profile for the evidence, mechanism and legal status.
What is in the vial
Common vial sizes.
Bacteriostatic water you add
Any amount works; it only changes how many units you draw. 2 mL is the most common. Standard vials hold 3 mL at most.
Amount per draw
Enter the amount you were given. The tool converts it; it never suggests one.
Syringe
U-100 insulin syringes. 100 units = 1 mL on all three; the marks differ.
Fill in the vial, the water and the amount per draw to see the result.
Half-life illustration
How NAC would decay on a daily schedule
Two example draws of the same size, one 24 hours ago and one now, decaying by the database half-life of ~5-6 hours. This shows the shape of the curve for a daily interval only. It is an illustration of exponential decay, not a schedule and not a recommendation; the size of the draw is arbitrary and the same in both.
How the math works for NAC
Concentration equals the amount on the NAC vial label, converted to micrograms, divided by the water volume in milliliters. The volume you draw equals the amount you enter divided by that concentration. Multiplying that volume by 100 converts it to units on a U-100 insulin syringe, and the calculator rounds to the nearest mark your syringe can show. Draws per vial is the total in the vial divided by the amount per draw.
Frequently asked questions
What is in a NAC vial before reconstitution?
A lyophilized (freeze-dried) powder. The label states the total amount in the vial, for example a number of mg, not a concentration per mL. Concentration only exists after bacteriostatic water is added: the label amount divided by the water volume. The calculator does that division and then converts the amount you enter into a syringe volume.
How do syringe units work for NAC?
Insulin syringes are marked in U-100 units, where 100 units equals 1 mL, on 0.3, 0.5 and 1 mL barrels. The calculator divides the NAC concentration by 100 to get the amount in each unit, then divides the amount you enter by that figure to get the mark to pull to. The result is rounded to the nearest readable mark on the syringe you choose: half-unit marks on 0.3 mL, 1-unit marks on 0.5 mL, 2-unit marks on 1 mL.
How long can reconstituted NAC be kept?
A multi-dose vial mixed with bacteriostatic water is commonly given a 28-day discard window, the USP 797 default, stored at 2 to 8 C and protected from light. Label the vial with the mix date and discard date; the calculator's print label does this. Cloudiness or floating particles mean the vial should not be used. Manufacturer or pharmacy labeling for NAC takes precedence over the default window.
Related
Educational use only. This database summarizes published research. It is not medical advice and contains no dosing protocols or recommendations for personal use. This calculator does not recommend a dose of NAC. It only converts the numbers you enter into a volume. The Longevity Archive does not provide medical advice.