Dosage research on NAD+

Preclinical research dose ranges

In published preclinical research on NAD+ and on its precursors (nicotinamide riboside, NR; nicotinamide mononucleotide, NMN), administered dose ranges in rodent studies have varied substantially by route of administration. Oral administration of NR and NMN in mice has most commonly fallen in the 100 to 500 milligram per kilogram per day range. Intraperitoneal administration of NAD+ itself in murine studies has fallen in the 50 to 500 milligram per kilogram range.

In-vitro studies on cultured cells (myotubes, hepatocytes, neurons, immune cells) have used NAD+ at micromolar to millimolar concentrations in the culture medium for cellular-redox endpoints. NMN and NR have been used at similar concentrations for NAD+-pool elevation endpoints. The in-vitro dose conventions are not directly translatable to in-vivo dosing because of the pharmacokinetic considerations involved in systemic delivery.

The aging-research preclinical literature has used long observation windows (multi-month protocols in aged rodent cohorts) with oral or intraperitoneal precursor administration. The mitochondrial-function and energy-metabolism literature has used shorter observation windows with acute or sub-chronic dosing protocols.

Dose-response considerations from the published literature

The published NAD+ literature has reported dose-response characteristics across the wide dose ranges described above, with mitochondrial-function and energy-metabolism endpoints scaling with administered dose across the milligram-per-kilogram range in murine models. NAD+-pool elevation in tissues scales with administered dose in both precursor-administration and direct NAD+-administration protocols.

Phase 1 dose-ranging trials of NR and NMN in adult humans have appeared in the published clinical literature, with doses tested in the 100 mg to 2000 mg per day range orally. The NNMT inhibitor literature is relevant to NAD+ research because NNMT activity regulates the methyl-group balance that affects NAD+ metabolism. Direct NAD+ administration in humans has appeared in a smaller number of pilots and case-series reports.

Reconstitution math and per-vial dose calculation

A 100 mg lyophilised NAD+ vial reconstituted with 2 mL of bacteriostatic water yields a stock concentration of 50 mg per mL. From this stock, a research aliquot of 0.1 mL contains 5 milligrams; an aliquot of 0.02 mL contains 1 milligram. Researchers working with the rodent in-vivo dose ranges further dilute the stock to a working concentration appropriate to the model and the body weight of the animal subject. NAD+ in solution is sensitive to pH and to oxidising conditions; the reconstituted aliquot should be refrigerated at 2 to 8 degrees Celsius, protected from light, and used within the observation window reported as stable in the published handling literature for the specific source material.

Research-protocol design considerations

Protocol-design choices in the published NAD+ literature reflect several recurring considerations. Dose selection depends on whether the protocol uses NAD+ itself, NR, NMN, or another precursor; the doses are not interchangeable on a milligram-per-kilogram basis because the pharmacokinetics and tissue-NAD+-pool-elevation kinetics differ across the compounds.

Route of administration in the published rodent work commonly uses oral administration for precursors (NR, NMN) and intraperitoneal or intravenous administration for NAD+ itself. Subcutaneous administration appears in a smaller subset of the literature. In-vitro studies deliver the compound directly into the culture medium at micromolar-to-millimolar concentrations.

The NAD+-pool-elevation kinetics across tissues is a protocol-design consideration unique to NAD+ research. Different tissues take up NAD+ and its precursors at different rates and metabolise them at different rates, and the tissue-specific NAD+-pool response to a given dose varies across the body. Protocol designs interested in tissue-specific endpoints should account for this consideration in their dose-tissue-time-course design.

References

1. Tarrago MG et al. A potent and specific CD38 inhibitor ameliorates age-related metabolic dysfunction by reversing tissue NAD+ decline. Cell Metabolism, 2018. [PMID 29719226]
2. Mills KF et al. Long-term administration of nicotinamide mononucleotide mitigates age-associated physiological decline in mice. Cell Metabolism, 2016. [PMID 27818143]
3. Yoshino J et al. Nicotinamide mononucleotide, a key NAD+ intermediate, in diet- and age-induced diabetes in mice. Cell Metabolism, 2011. [PMID 21982712]
4. Eckert MA et al. Proteomics reveals NNMT as a master metabolic regulator of cancer-associated fibroblasts. Nature, 2019. [PMID 39067875]
5. Hong S et al. Nicotinamide N-methyltransferase regulates hepatic nutrient metabolism through Sirt1 protein stabilization. Nature Medicine, 2015. [PMID 26011344]
6. Liu D et al. Reduced calorie diet combined with NNMT inhibition establishes a distinct microbiome composition that protects against obesity. iScience, 2022. [PMID 35013352]