Human randomized trial

Placebo-controlled randomized double-blind parallel-group trial of the safety of overdose intake of nicotinamide mononucleotide

Ryota Nakajima, Hidekazu Watanabe, Kunio Nakata, Kei Yamana, Masahiko Tokushima

Fundamental Toxicological Sciences · 2025 · 12(3):67–77

Original publication

Study at a glance

Design: Placebo-controlled, randomized, double-blind, parallel-group overdose safety trial; 4 weeks
Population or model: Healthy adults
Sample size: 30 participants
Intervention: Placebo, NMN 750 mg/day, or NMN 1,500 mg/day for 4 weeks
Publication type: Randomized controlled safety trial
Evidence class: human-study
Research area: High-dose safety and tolerability
Trial registration: Not stated in verified source for this record.

Study endpoints

Adverse events
Clinical laboratory safety
Physical and physiological measures
Blood NAD-related measures

Plain-language summary

This randomized double-blind safety study tested 750 or 1,500 mg/day NMN against placebo for four weeks in 30 healthy adults.

The study was designed as an overdose-intake safety assessment rather than an efficacy trial. Its main contribution is short-term tolerability information at doses higher than those used in many earlier NMN studies.

The small sample and four-week duration mean it cannot establish uncommon adverse-event risks or long-term safety.

Key findings

The trial directly evaluated 750 and 1,500 mg/day oral NMN for four weeks.
The publication reported short-term safety and laboratory monitoring across the high-dose groups.
The study was designed for safety, not clinical efficacy.
Commercial Teijin/NOMON affiliations were present among four of five authors.

Limitations

Only 30 participants.
Only four weeks of exposure.
Not powered to detect rare adverse events.
Healthy-adult findings may not generalize to people with significant chronic disease.
Strong commercial affiliations require transparent interpretation.

Funding and transparency

Funding

Four authors were affiliated with Teijin Limited and NOMON Co. Ltd.; the full publication should be consulted for the formal funding statement.

Competing interests

Ryota Nakajima, Hidekazu Watanabe, Kunio Nakata and Kei Yamana were affiliated with Teijin Limited and NOMON Co. Ltd.

HealthspanX observation

This paper is primarily a safety record and should not be presented as efficacy evidence.

Interpretive weight

Limited

Randomized high-dose safety trial is useful for short-term tolerability, but small sample size, four-week exposure and direct commercial affiliations limit generalization.

This record summarizes a publication; it is not medical advice or a claim that a HealthspanX product reproduces the study's results. Report a correction.

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