Blair E, Miller A, McDonald R.

Introduction: NAD+ is a critical coenzyme for cellular energy production, DNA repair, and sirtuin activity, with levels known to decline with age. While oral NAD+ supplementation is proposed for healthy aging benefits, its efficacy in raising intracellular NAD+ levels remains debated; precursors such as nicotinamide have shown to increase blood levels (along with other precursors. This study was designed to determine the effect of oral liposomal NAD+ preparations on human intracellular NAD+ concentrations and is the first successful study of its kind.

Methods: A total of 14 individuals (n=14) participated in this non-randomized, crossover study. Participants took two different preparations of a liposomal NAD+ supplement daily for two weeks: 1000 mg of CELLg8 NAD and 1,000 mg CELLg8 cwd, separated by a three-week washout period. Intracellular NAD+ levels were measured at baseline for each dose period and after 14 days of supplementation.

Results: After two weeks of supplementation with a 1,000 mg liposomal NAD+ dose, participants showed an average increase of over 64% in intracellular NAD+ levels compared to baseline (p<0.01) for both NAD+ preparations.

Conclusion: This study is the first example of daily oral supplementation with a liposomal NAD+ preparation significantly increasing intracellular NAD+ levels in humans, particularly at the 1,000 mg dose. This suggests that liposomal delivery is an effective method for enhancing NAD+ bioavailability within cells. 

Introduction

NAD+ is a coenzyme that participates in numerous metabolic reactions, particularly those involved in energy production. It exists in two forms: NAD+ and NADH, which can interconvert in redox reactions. NAD+ is essential for cellular respiration and the generation of ATP (adenosine triphosphate), the primary energy currency of cells. In the process of cellular respiration, NAD+ accepts electrons from molecules like glucose during glycolysis and the citric acid cycle. These electrons are then transferred to the electron transport chain, where NADH is converted back to NAD+ while generating ATP. Thus, NAD+ acts as a critical mediator in energy production, ensuring the efficient functioning of cells.

In addition to its influence on energy production, NAD+ plays a significant role in DNA repair mechanisms.1 Enzymes involved in DNA repair, such as PARPs (poly ADP-ribose polymerases) require NAD+ as a substrate. NAD+ depletion has been linked to impaired DNA repair efficiency, leading to an accumulation of DNA damage. This damage may contribute to aging and the development of various diseases.1,2

NAD+ is also an essential cofactor in healthy aging mechanisms via its effects on sirtuin coenzyme activity. Sirtuins are a family of enzymes that regulate various cellular processes, including gene expression, DNA repair, and metabolism. NAD+ has been shown to activate sirtuins, which has demonstrated promising effects in animal and human studies.3-5

NAD+ levels tend to drop with age, so increasing NAD+ levels may be helpful for healthy aging. Supplementation with NAD+ precursor niacinamide has been shown to benefit general quality of life such as healthy sleep, metabolism, and general health.6 It has been debated whether oral supplementation with NAD+ increases blood levels or cellular levels.7 A systematic search of the scientific literature does not result in any human studies of NAD+ oral supplementation in humans. Therefore, we set out to examine whether intracellular NAD+ levels would change after oral supplementation with a liposomal preparation of NAD+, since previous studies have shown increased blood levels of other nutrients after taking specific liposomal supplements. (CELLg8 -Wellington, CO). 8-10 

Methods

In this study, 14  (n = 14) individuals took two different doses of a liposomal NAD+ supplement – 1000 mg CELLg8 NAD (novel liposomal preparation) and 1,000 mg CELLg8cwd NAD (novel and water dispersible liposomal preparation) – each daily for two weeks. Intracellular NAD+ levels were measured at the start of the study to check baseline levels (time 0).  Blood was collected via finger stick dried blood spot and intracellular NAD+ testing was performed at Jinfiniti Precision Medicine Laboratory, Augusta, GA.11Following the initial 14-day supplementation period, intracellular NAD+ levels were reassessed (time 2). To minimize carryover effects, a three-week washout period was implemented prior to the crossover phase. After the washout period, another baseline NAD+ test was performed (time 3), followed by two weeks taking the other dose. A final blood test was then done to check intracellular NAD+ levels again (time 4). 

Results

After two weeks taking the 1,000 mg CELLg8 cwd or CELLg8 NAD preparation, an average 64% increase in intracellular NAD+ levels was seen. No adverse events were recorded; however, one participant who was taking an SSRI medication felt an increase in depressive symptoms and dropped out of the study.

1000 mg CELLg8 NAD+

1000 mg CELLg8cwd NAD+

Discussion

This study is the first published clinical trial of the effect of NAD+ oral supplementation on intracellular levels of NAD+ in humans. Supplementing 1000 mg of liposomal NAD+ increased NAD+ levels, on average, more than 64% over baseline levels after 14 days (p<0.01) for both preparations. 

It has previously been thought that oral supplementation of pre-formed NAD+ would not increase intracellular NAD+ levels in the body, either because of poor absorption, degradation of the molecule in the stomach, or its size inhibiting cellular uptake. This study demonstrates that a daily dose of liposomal NAD+ indeed does increase intracellular NAD+ and appears to be an efficient way to quickly increase NAD+ levels, instead of supplementing with a precursor such as niacinamide, which relies on efficient enzymatic conversion to NAD+. These findings suggest a potential clinical protocol involving a high-dose induction phase (1,000 mg) for 14 days to optimize intracellular levels, followed by a lower maintenance dose to sustain therapeutic gains.

Authors: Emek Blair, PhD , Alan L. Miller, ND, Rina McDonald.

Authors Contribution: Emek Blair: Conceptualization, Methodology, Data Curation, Formal Analysis, Writing- Review and Editing. Alan Miller: Visualization, Investigation, Resources, Writing- Original Draft, Writing- Review and Editing. Rina McDonald: Study Coordination, Data Collection.

Competing Interests and Funding: Dr. Blair is the owner of CELLg8®, which funded this study. Dr. Miller and Ms. McDonald are employed by CELLg8®, which funded this study.

Ethics Statement: This study was approved by the Institute of Regenerative and Cellular Medicine institutional review board (approval #IRCM-2023-374).

References

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10. https://www.jinfiniti.com/product/intracellular-nad-test/