A side-by-side analysis of NAD+ precursors based on empirical data, molecular structure, and peer-reviewed bioavailability studies. No brand comparisons — just the chemistry.
Nicotinamide Mononucleotide
Nicotinamide Riboside
Nicotinamide Adenine Dinucleotide
| Property | NMN | NR | NAD+ |
|---|---|---|---|
| Molecular Weight | 334.22 g/mol C11H15N2O8P | 255.25 g/mol C11H16N2O5 | 663.43 g/mol C21H27N7O14P2 |
| Bioavailability | 85/100 High. Direct transport via the Slc12a8 transporter. | 65/100 Moderate. Rapidly degraded in the gut; converted to Nam. | 25/100 Very low orally. IV administration bypasses gut degradation. |
| Delivery Routes | Sublingual, Liposomal, Oral Capsule, Oral Powder | Oral Capsule, Oral Powder | Iv Drip, Subcutaneous |
| Regulatory Status | FDA Review Excluded from dietary supplement classification by the FDA in 2022 pending NDIN review. | FDA GRAS Generally Recognized As Safe; approved as a dietary ingredient (NDIN 822 in 2015). | Clinical Only Administered in medical clinics; not a dietary supplement in IV form. |
| Studies | 2 notable Typical dose 250-500 mg/day | 2 notable Typical dose 300-600 mg/day | 1 notable Typical dose 250-1,000 mg IV drip over 2-4 hours |
Bioavailability scores are relative — not absolute fractions. They reflect a synthesis of published pharmacokinetic data across the major routes of administration. Regulatory status reflects U.S. FDA classification; other jurisdictions may differ. “Top pick” denotes the precursor with the most mechanistically-supported oral route based on current human data — not a medical recommendation.