Primary source analyzed: Yi L, Maier AB, et al. “The efficacy and safety of β‑nicotinamide mononucleotide (NMN) supplementation in healthy middle‑aged adults: a randomized, multicenter, double‑blind, placebo‑controlled, parallel‑group, dose‑dependent clinical trial.” GeroScience (2022). PMCID: PMC9735188.

Study registration: ClinicalTrials.gov NCT04823260; CTRI/2021/03/032421
Disclaimer: This article summarizes a published clinical trial. It is not medical advice and does not claim to diagnose, treat, cure, or prevent any disease.

NMN Trial: Dose Dependent, Functional Gains & Safety

Prepared by: Research & Development Division, MONOmolecule™
Affiliation: Independent literature analysis based on PMC9735188
Date: January 2026

Abstract

β‑Nicotinamide mononucleotide (NMN) is a precursor in the NAD salvage pathway and is widely studied for potential effects on age‑associated NAD decline. This web dissertation reviews a randomized, multicenter, double‑blind, placebo‑controlled, parallel‑group, dose‑dependent clinical trial in 80 healthy middle‑aged adults (40–65 years) who received placebo or NMN at 300 mg/day, 600 mg/day, or 900 mg/day for 60 days. The primary endpoint was change in blood NAD (serum total NAD⁺ + NADH). Secondary endpoints included 6‑minute walking test, blood biological age (Aging.Ai 3.0), HOMA‑IR, and SF‑36 quality‑of‑life scores, alongside safety labs and adverse event monitoring.

Across 60 days, all NMN doses significantly increased blood NAD vs baseline and placebo (p < 0.001), with higher NAD in 600 mg and 900 mg groups. Functional performance improved: 6‑minute walk distance increased significantly in all NMN groups vs placebo at days 30 and 60, with the largest gains at 600–900 mg. NMN was well tolerated up to 900 mg/day, with no serious adverse events and no NMN‑related adverse events reported. Blood biological age increased in placebo but remained stable in NMN groups, producing a significant between‑group difference at day 60.

Interpretation: In this study, NMN raised blood NAD and was safe over 60 days, while clinical efficacy signals (walking endurance and self‑reported health) appeared strongest around 600 mg/day, with no clear added benefit at 900 mg/day for key endpoints.

1. Introduction

NAD (nicotinamide adenine dinucleotide) is a central coenzyme in cellular energy metabolism and is involved in pathways associated with DNA repair and stress responses. Multiple preclinical studies suggest NAD levels decline with age and that NAD‑precursor supplementation (including NMN) can elevate NAD and influence physiological outcomes in animal models.

Human NMN evidence has historically shown mixed results across trials due to differences in:

• participant populations (healthy vs overweight/obese; male‑only vs female‑only),
• dose selection (commonly 250–300 mg/day fixed doses),
• sampling matrices (serum vs whole blood vs PBMC),
• analytical methods (colorimetric vs LC‑MS/MS).

This clinical trial was designed to address a key gap: dose‑dependent NMN effects (300–900 mg/day) in healthy middle‑aged men and women using a rigorous randomized controlled design.

2. Materials and Methods

2.1 Trial Design

• Type: randomized, multicenter, double‑blind, placebo‑controlled, parallel‑group, dose‑dependent
• Duration: 60 days
• Participants: 80 healthy adults, 40–65 years, ~59% female
• Groups (n=20 each): placebo, NMN 300 mg/day, NMN 600 mg/day, NMN 900 mg/day
• Dosing: once daily orally before breakfast

2.2 Key Outcomes

Primary

• Blood NAD concentration (serum total NAD⁺ + NADH) measured at days 0, 30, 60

Secondary

• 6‑minute walking test (treadmill‑based) at days 0, 30, 60
• Blood biological age via Aging.Ai 3.0 (19 lab parameters) at day 0 and day 60
• HOMA‑IR (fasting glucose + fasting insulin) at day 0 and day 60
• SF‑36 total score at day 0, 30, 60
• Safety labs (hematology/chemistry/urinalysis), vitals, physical exams, ECG; adverse event monitoring

2.3 Compliance and Analysis

• Compliance considered adequate at 75–125% of scheduled doses.
• Statistical approach included mixed models for repeated measures for outcomes measured across time points.

3. Results

3.1 Blood NAD (Primary Endpoint): Significant, Dose‑Dependent Increase

Baseline serum NAD values were variable across groups. After supplementation:

• All NMN groups showed significant NAD increases at day 30 and day 60 vs baseline (p ≤ 0.001)
• All NMN groups were significantly higher vs placebo at both timepoints (p < 0.001)
• NAD was highest at 600 mg and 900 mg, with:
  • 600 mg > 300 mg at day 30 and day 60 (significant)
  • 900 mg vs 600 mg: no significant difference (plateau signal)

Reported means (Table 2):

• 300 mg: ~11.8 → 29.8 (day 30) → 32.6 (day 60) nM
• 600 mg: ~7.95 → 39.0 → 45.3 nM
• 900 mg: ~10.5 → 43.1 → 48.5 nM
• Placebo: no significant change

3.2 Physical Performance: 6‑Minute Walking Distance Improved vs Placebo

• Compared with placebo, all NMN groups walked significantly farther at day 30 and day 60 (p < 0.01).
• 600 mg outperformed 300 mg at both timepoints (significant).
• 900 mg did not significantly exceed 600 mg, again suggesting a plateau.

Reported means (Table 2):

• 600 mg: ~290 m → 400 m → 435 m
• 900 mg: ~323 m → 425 m → 480 m
• Placebo: ~325 m → 310 m → 330 m

3.3 Blood Biological Age: Stable in NMN Groups vs Increase in Placebo

• Placebo group showed a significant increase from baseline to day 60 (p = 0.029).
• NMN groups showed no significant within‑group change, and between‑group differences vs placebo were significant (p < 0.05).

3.4 Insulin Resistance (HOMA‑IR): No Significant Improvement vs Placebo

• No significant differences between NMN and placebo at day 60.
• Within groups, HOMA‑IR increased significantly in the 600 mg and 900 mg groups vs baseline, but this did not translate into statistically significant differences vs placebo.

3.5 Quality of Life (SF‑36): Improved vs Placebo (Especially at Day 60)

• At day 60, all NMN doses showed significantly better SF‑36 changes vs placebo (p < 0.01).
• At day 30, improvements were significant for 600 mg and 900 mg (not for 300 mg).

4. Safety and Tolerability

4.1 Adverse Events

• Total AEs: 9 events in 7 participants
• Placebo: 6 AEs in 5 participants
• 300 mg: 3 AEs in 2 participants
• 600 mg & 900 mg: 0 AEs reported
• Serious AEs: none
• NMN‑related AEs: none
• Dropouts due to AEs: none

4.2 Laboratory and Clinical Safety

• No clinically meaningful abnormalities in vitals/physical findings.
• Most lab parameters did not differ vs placebo; a few isolated statistical differences occurred (e.g., LDL at 900 mg; uric acid nitrogen at 600 mg), but authors report no abnormality observed across participants.

Conclusion on safety (per authors): NMN up to 900 mg/day for 60 days was safe and well tolerated in this cohort.

5. Discussion

5.1 Efficacy Signal: NAD Elevation Is Clear and Dose‑Responsive

The trial provides one of the more direct, dose‑dependent demonstrations that oral NMN can significantly increase serum NAD (NAD⁺ + NADH) in healthy middle‑aged adults over 60 days. Notably, the response appears to plateau around 600 mg/day, with 900 mg/day not consistently outperforming 600 mg/day in primary comparisons.

5.2 Functional Outcome: Walking Endurance Improved

The statistically significant improvement in 6‑minute walk distance suggests a meaningful functional signal consistent with the broader hypothesis that improving NAD availability may support energy metabolism and endurance. However, the study measured a specific performance test under controlled conditions and does not prove long‑term clinical outcomes.

5.3 Biological Age: A Promising but Model‑Dependent Endpoint

The trial used Aging.Ai 3.0, a blood‑parameter‑based biological age estimator. Stability in NMN groups vs increase in placebo is intriguing, but biological age models vary, and confirmation using other aging clocks and longer follow‑up would strengthen the claim.

5.4 Metabolic Outcomes: No Clear Improvement in Insulin Resistance

Unlike some NMN trials in prediabetic/obese populations, this study in healthy adults did not show improvement in HOMA‑IR vs placebo. This may reflect baseline metabolic health, short duration, or endpoint sensitivity.

6. Conclusion

In this 60‑day randomized, double‑blind, placebo‑controlled trial in healthy adults aged 40–65:

• NMN significantly increased blood NAD at 300, 600, and 900 mg/day.
• Walking endurance improved in NMN groups vs placebo at days 30 and 60.
• Blood biological age increased in placebo but remained stable in NMN groups.
• NMN was well tolerated up to 900 mg/day, with no NMN‑related adverse events reported.
• Across multiple endpoints, 600 mg/day appeared to deliver near‑maximal benefit, with no consistent additional gain at 900 mg/day.

7. Limitations

• Sample size: 80 total participants (20 per group)
• Duration: 60 days (short; long‑term outcomes unknown)
• Matrix and method: NAD measured in serum as NAD⁺ + NADH via colorimetric kit; results may differ from whole blood LC‑MS/MS methods
• Conflicts of interest: funding and some authors employed by companies related to investigational product (as disclosed in the paper)
• Endpoints: improvements in walk test and SF‑36 are supportive but do not prove disease prevention or longevity extension

8. References

1. Yi L, Maier AB, et al. GeroScience. 2022;45(1):29–43. doi:10.1007/s11357-022-00705-1. PMCID: PMC9735188.

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