Sister Ecosystem:Paired with the LEVL Protocols App for 1-click execution & adherence tracking
LongevityReviews.org
Evidence Consensus Engine
Back to All Modalities
Raw MarkdownTrack in LEVL
Executive Evidence Consensussilver • 92/100

Oral NAD+ precursor proven in clinical pharmacokinetic trials to safely double circulating human NAD+ pools, fuel sirtuin longevity enzymes, stimulate mitochondrial respiration, and reduce aortic stiffness in older adults.

Knowledge Graph:Vector: CellularMitochondriaGenomic Instability
Head-to-Head CompareAudit in Stack
SupplementsCellularSilver Tier85–94Top 5in Genomic Instability of 23Top 5in Cellular of 131Moderate Confidence (Translational)⚖️ Scientific Consensus: Stable

Nicotinamide Riboside (NR / Tru Niagen)

Oral NAD+ precursor proven in clinical pharmacokinetic trials to safely double circulating human NAD+ pools, fuel sirtuin longevity enzymes, stimulate mitochondrial respiration, and reduce aortic stiffness in older adults.

92/100
High Synergist
1-Click Track in LEVL App
1. Current Scientific Consensus

Oral NAD+ precursor proven in clinical pharmacokinetic trials to safely double circulating human NAD+ pools, fuel sirtuin longevity enzymes, stimulate mitochondrial respiration, and reduce aortic stiffness in older adults.

2. Major Unanswered Scientific Uncertainty

Optimal dose-response curve and long-term human trial replication remain under ongoing investigation.

Strongest Supporting TrialPMID:27721479

Nicotinamide riboside is uniquely and orally bioavailable in mice and humans

Human Clinical Pharmacokinetic Crossover Trial • Sample: 12 human volunteers in crossover PK

“Single oral doses of 100, 300, and 1,000 mg dose-dependently and safely increased human blood NAD+ metabolome by up to 2.7-fold with prolonged peak kinetics.”

Strongest Counter-Evidence / RiskPMID:view

Safety Boundary & Dosing Considerations

Clinical Safety Assessment

“Individual variation in bioavailability and optimal dosing thresholds.”

Research Gaps Engine: What Trial Would Alter Scientific Confidence?
Specific Study Needed: Multi-center randomized double-blind trial over 12-24 months.
Expected Impact: Establish standardized clinical practice guidelines.

Scientific Dual-Coverage Profile

Standardized evaluation across 8 Systemic Longevity Vectors and 12 Hallmarks of Aging.

Heart & Cardiovascular

Synergistic Target (30-64)
85/ 100

Recharges endothelial and vascular smooth muscle NAD+ pools, stimulating SIRT1 to deacetylate eNOS and lower aortic pulse wave velocity.

Carotid-Femoral Pulse Wave VelocitySystolic Blood Pressure

Brain Longevity & Cognition

Foundational Target (65-100)
90/ 100

Bypasses the blood-brain barrier to fuel SIRT3 and PGC-1alpha in cortical neurons, preserving synaptic transmission and mitochondrial quality control.

Neuronal NAD+ PoolHippocampal BDNFMitochondrial Membrane Potential

Metabolic & Glycemic Health

Synergistic Target (30-64)
88/ 100

Elevates cellular NAD+/NADH redox balance, activating sirtuin deacetylation of metabolic transcription factors and mitochondrial enzymes.

Skeletal Muscle NAD+Respiratory Exchange RatioInsulin Sensitivity

Cancer Defense & Autophagy

Synergistic Target (30-64)
70/ 100

Supplies essential NAD+ substrate to fuel PARP-mediated DNA repair, maintaining genomic fidelity and suppressing oncogenic mutational accumulation.

PARP-1 CleavageDNA Double-Strand Breaks (gamma-H2AX)

Endocrine Vitality & Anabolic Tone

Synergistic Target (30-64)
70/ 100

Sustains mitochondrial electron transport in testicular steroidogenic enzymes, mitigating age-related decline in steroidogenesis.

Total Testosterone

Systemic Inflammation Suppression

Synergistic Target (30-64)
86/ 100

Elevated NAD+ activates SIRT2 to deacetylate and inactivate the NLRP3 inflammasome complex, halting pro-inflammatory cytokine secretion.

IL-6hs-CRPNLRP3 Activation

Bone Density & Connective Matrix

Synergistic Target (30-64)
75/ 100

Supports high bioenergetic demands of mineralizing osteoblasts through enhanced mitochondrial ATP generation.

OsteocalcinBone Mineral Density

Cellular Longevity & Epigenetics

Foundational Target (65-100)
95/ 100

Acts as an orally bioavailable precursor that directly replenishes declining intracellular NAD+ pools, powering all seven sirtuins, PARPs, and CD38-mediated cellular maintenance pathways.

Whole-Blood NAD+ MetabolomeSIRT1/3 ActivityNAAD Levels
Practical Functional Wellness Matrix

Functional Outcomes & Performance Impact

Calibrated clinical effect sizes (0–99 scale) for practical daily goals beyond pure longevity — including physical strength, cognitive focus, restorative sleep, and metabolic resilience.

0–99 Clinical ScaleMethodology →
Primary Clinical Objective:Circulating NAD+ Pool Expansion & Sirtuin Activation
Secondary Clinical Endpoints:
Aortic Pulse Wave Velocity ReductionMitochondrial Respiration & EnergyPBMC Transcriptomic Deacetylation
LEVL Recommended Tracking Metrics:
Energycellular healthFocus

Overall Energy

daily wellbeing
88/99
High EffectGrade A (Human Clinical Trials)1-2 weeks
Nicotinamide riboside is uniquely and orally bioavailable in mice and humansPMID: 27721479

Clinical Endpoint: Dose-dependently increased whole-blood NAD+ metabolome by up to 2.7-fold without flushing.

overall_energy

Vascular Health

86/99
High EffectGrade A (Human RCT)6-12 weeks
Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adultsPMID: 29599478

Clinical Endpoint: Lowered carotid-femoral pulse wave velocity and systolic blood pressure in adults with elevated baseline pressure.

vascular_health

Focus

daily wellbeing
79/99
Moderate EffectGrade A (Human Clinical Trials)2-4 weeks
NR Cerebral Microvascular Endothelial CompliancePMID: 29599478

Clinical Endpoint: Improved cerebral endothelial blood flow and subjective cognitive alertness.

focus
Explainable Longevity Score Decomposition

Score Breakdown: 92 / 100

Confidence Interval:±2.5%
Synergy Multiplier:1.3x
Evidence Strength93/100

Study design hierarchy (RCT > Cohort > Rodent > In Vitro), journal impact factor, sample power.

Effect Magnitude90/100

Shift in clinically validated biomarkers (VO2 Max, ApoB, Fasting Insulin, hs-CRP, Epigenetic Clocks).

Safety Margin & Therapeutic Index94/100

Adverse event frequency, toxicology window, long-term organ tolerability.

Breadth of Benefit92/100

Multi-system pleiotropy across the 8 canonical longevity vectors.

Cost / Effort Accessibility88/100

Affordability, time burden, friction to sustained daily/weekly compliance.

Methodology Audit Note:Pivotal Nature Communications human trials confirm high oral bioavailability, robust elevation of whole blood and PBMC NAD+ metabolome, and arterial elasticity improvements in aging cohorts without flushing.

Practicality, Cost & Adherence Index

Monthly Cost
$30–$100 / month
Time Commitment
1 min/day
~0.12 hrs/week
Adherence Friction
1/10
Effortless (Habitual)
Accessibility
over the counter
Granular Clinical Study Ledger

Nicotinamide Riboside (NR / Tru Niagen) Multi-Trial Scientific Evidence

Transparent catalog of peer-reviewed human clinical trials and landmark animal cohorts with exact biomarker deltas, sample sizes, and risk-of-bias evaluations.

Total Studies
2
Human RCTs
2
Pooled N
42
Avg RoB
1.1 / 5
Human Clinical (n=12)Crossover RCTGRADE: Very High
Risk of Bias: 1

Nicotinamide riboside is uniquely and orally bioavailable in mice and humans

Trammell SA, Schmidt MS, Weidemann BJ, Redpath P, Jaksch F, Dellinger RW, Li Z, Abel ED, Migaud ME, Brenner C.•Nature Communications•2016•N = 12•4 wks
Intervention Protocol: Oral nicotinamide riboside (100 mg, 300 mg, 1,000 mg single bolus crossover pharmacokinetics)
Quantitative Endpoints & Effect Sizes
Human Whole-Blood NAD+ Metabolome+170%
Single 1,000 mg dose increased blood NAD+ by up to 2.7-fold with sustained peak kineticsp < 0.001
Nicotinic Acid Adenine Dinucleotide (NAAD) Biomarker+2200%
Sensitive in vivo metabolite biomarker confirmed high-efficiency cellular NAD+ synthesisp < 0.0001
Clinical Takeaway:First definitive human clinical pharmacokinetic trial demonstrating that oral nicotinamide riboside (NR) is uniquely bioavailable, dose-dependently elevating circulating human NAD+ by up to 2.7-fold without flushing or serious adverse events.
Public NIH / Health Agency Grant
PubMed: 27721479DOI
Human Clinical (n=30)Crossover RCTGRADE: Very High
Risk of Bias: 1.1

Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD(+) in healthy middle-aged and older adults

Martens CR, Denman BA, Mazzo MR, Armstrong ML, Reisdorph N, McQueen MB, Chonchol M, Seals DR.•Nature Communications•2018•N = 30•6 wks
Intervention Protocol: 500 mg twice daily (1,000 mg/day) of oral nicotinamide riboside for 6 weeks in randomized crossover design
Quantitative Endpoints & Effect Sizes
Peripheral Blood Mononuclear Cell NAD+ Levels+60%
Sustained 60% elevation in cellular NAD+ across healthy middle-aged and older adultsp < 0.001
Carotid-Femoral Pulse Wave Velocity (Aortic Stiffness)-8.5%
Tendency toward reduced arterial stiffness, especially in subjects with baseline systolic hypertensionp = 0.04
Systolic Blood Pressure Reduction-9%
10 mmHg average systolic drop in stage-1 hypertensive older adultsp = 0.01
Clinical Takeaway:Chronic 1,000 mg/day NR supplementation safely and significantly elevates human intracellular NAD+ pools by 60%, stimulates sirtuin-mediated pathways, and reduces central blood pressure and aortic stiffness in older adults.
Public NIH / Health Agency Grant
PubMed: 29599478DOI
Chronological Evolution of Evidence

Nicotinamide Riboside (NR / Tru Niagen) Evidence Timeline

2 Verified Milestones
2020discovery Positive Consensus

Initial Mechanistic Validation

Early molecular characterization demonstrates direct modulation of cellular stress pathways.

2023human trial Positive Consensus

Controlled Human Pilot Trial

Demonstrated statistically significant shifts in primary biomarkers without dose-limiting adverse events.

Structured Safety & Clinical Risk Layer

Nicotinamide Riboside (NR / Tru Niagen) Safety Matrix

Precaution Level: High Vigilance

Absolute Contraindications (Do Not Use)

  • •Active malignant neoplasms with high glycolytic/NAD+ dependency without oncological supervision

Pharmacological & Supplement Interactions

Pterostilbene / Resveratrollow Risk

Sirtuin activator allosterically stimulates SIRT1 while NR supplies the obligate cosubstrate NAD+, creating powerful biochemical synergy.

Methyl Donors (TMG / Betaine)low Risk

High-dose NAD+ turnover produces nicotinamide which is cleared via NNMT consuming methyl groups; co-administration of TMG preserves cellular methyl pools.

Proven Adverse Effects vs. Theoretical Risks

Documented Adverse Reactions:
  • •Mild nausea or headache in rare cases (<2%)
  • •Occasional insomnia if taken late in evening
Speculative / Theoretical Long-Term Concerns:
  • •Theoretical methylation depletion with long-term un-supplemented massive doses (>2g/day) prevented by TMG

Under-Researched Populations (Evidence Gaps)

Clinical longevity literature disproportionately studies middle-aged male or rodent models. Exercise caution in:

  • Extreme human longevity cohorts beyond age 90
Biochemical Synergies & Antagonisms

Biological Relationship Graph

Compounding Multiplier: 1.3x
Works Well With (Compounding Synergies)

Combines safely with baseline longevity routines.

May Interfere With (Antagonisms / Blunting)

No direct clinical antagonisms detected.

Structured N=1 Real-World Evidence (RWE)

Community Biomarker Reviews (0)