| Dimension | Scoring Notes | Score |
|---|---|---|
| Study Design | A 2026 PRISMA-guided systematic review identified 33 human intervention studies (28 randomized, 5 nonrandomized) on NAD+ precursors through October 2025. Multiple independent RCTs exist, but no single large Phase III trial anchors the field — capped below the maximum. |
20 / 25 |
| Sample Size | Individual trials are mostly small (20–95 participants). Cumulative human exposure across 28 RCTs is meaningful for a research peptide-adjacent compound, but no single trial breaks 200 participants. |
8 / 20 |
| Replication | NR and NMN's effect on raising circulating NAD+ has been replicated across independent academic groups internationally, most recently in a head-to-head precursor comparison published in Nature Metabolism (January 2026). |
15 / 20 |
| Journal Impact Factor | The 2026 precursor-comparison study was published in Nature Metabolism (IF ~17). Other studies span Aging Cell, Nutrients, and Journal of Clinical Investigation — solid mid-to-high tier journals. |
12 / 15 |
| Funding Independence | Mixed funding profile. The 2026 Nature Metabolism precursor comparison was Nestlé Health Science-funded; a meaningful academic and NIH-adjacent presence elsewhere in the literature keeps this above pure industry dominance. |
7 / 10 |
| Population Diversity | Trials span a range of ages and some international cohorts (US, Japan, China, Switzerland), but most precursor RCTs concentrate on healthy or condition-specific adult populations — moderate, not broad, diversity. |
3 / 5 |
| Researcher h-Index | Researchers leading the 2026 Nature Metabolism comparison and related precursor work have solid, established academic profiles, though not uniformly elite across the full NAD+ literature. |
4 / 5 |