Key Points
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NMN helped maintain thickness in a specific area of the retina
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Placebo group lost retinal thickness in that area, NMN stayed more stable
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Only one retinal area measured showed a meaningful difference
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Vision stayed stable in both groups
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NMN was well-tolerated over 24 weeks, with no major safety concerns
Study Overview
Fourteen older men with type 2 diabetes were randomized into two groups:
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NMN group: 7 men received 250 mg oral NMN daily for 24 weeks
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Placebo group: 7 men received an oral placebo daily for 24 weeks
NMN Helped Maintain Retinal Thickness
Of the nine retinal areas measured, one region showed significant improvement.
“In the temporal region of the outer circle, the measurement changes in the NMN and placebo groups were +1.14 μm and −2.77 respectively, and the difference was statistically significant.”
In that area:
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The NMN group stayed about the same or increased slightly.
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The placebo group lost retinal thickness.
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The difference between groups was statistically significant.
This means the placebo group showed retinal thinning over the study period, while the NMN group showed a slight increase in retinal thickness.
The Trend Held When Excluding Other Ocular Diseases
The researchers repeated the analysis after excluding those with other eye diseases, and the same general pattern remained.
“The placebo group showed a trend toward a thinner retina compared to the NMN group, which was similar to the findings in the analysis including all eyes.”
The NMN group still looked better than placebo in the temporal outer retina, but the result was no longer statistically significant.
Conclusion
This small exploratory study found that 250 mg/day of NMN for 24 weeks was well tolerated in older men with type 2 diabetes and physical frailty.
“For the temporal retinal thickness, a decrease was observed in the placebo group, whereas a slight increase was observed in the NMN group.”
NMN was linked with better preservation of retinal thickness in one specific region of the retina called the temporal outer subfield. The placebo group showed thinning in that region, while the NMN group remained more stable.
“Administration of NMN might have prevented the thinning of the temporal region…it is possible that NMN supplementation may preferentially mitigate retinal thinning in vulnerable regions such as the temporal macula.”
Larger studies are needed to confirm whether NMN can meaningfully support retinal structure or visual function over time.
“Oral NMN administration was safe both systemically and locally in the eyes. Based on the retinal thickness results, NMN may be efficacious in mitigating age-related alterations in the retina.”
