A combination NAD+ treatment has recently been shown to have significant benefits for mice, according to a study published on April 9, 2026. This combination treatment, referred to as N + A, encompasses the administration of nicotinamide mononucleotide (NMN) and the inhibition of the enzyme CD38 through apigenin. In this context, NMN directly increases NAD+, while apigenin prevents its depletion. The results demonstrate that the combination of these two approaches had stronger effects on musculoskeletal and gut health compared to either treatment when administered individually.

A Well-Documented Issue

NAD+ (Nicotinamide adenine dinucleotide) is one of the most well-documented compounds in biological research, especially in relation to aging. Precursor supplementation has consistently exhibited measurable benefits. For example, clinical trials indicate that nicotinamide riboside (NR) reduces mortality in individuals suffering from chronic obstructive pulmonary disorder [1], while another study demonstrated that nicotinamide mononucleotide (NMN) can restore insulin sensitivity [2]. On the downside, the enzyme CD38, which consumes NAD+, increases with age [3]. Inhibition of CD38 by apigenin [4] has been associated with beneficial effects across various biological systems.

The combination of NMN and apigenin in a formulation known as N + A has been previously explored. Research demonstrated that N + A combats inflammation and senescence in muscle precursor cells [5]. This study builds on earlier work by administering the N + A formulation to various cell types and conducting _in vivo_ experiments in mice.

Restoring NAD+ Restores Cellular Function

The initial phase of the study involved analyzing publicly available biopsy data to assess four types of cells: myofibers, muscle stem cells, chondrocytes, and osteoblasts. As anticipated, older samples exhibited a reduced number of muscle stem cells in comparison to younger samples. A gene expression analysis indicated that numerous genes linked to NAD+ were downregulated in the elderly samples.

The researchers subsequently conducted an experiment, inducing senescence in three types of musculoskeletal cells via oxidative stress, doxorubicin, or replication stress. Each of these methods diminished the presence of NAD+ in the cells, leading to a decline in available ATP and impairing differentiation capabilities.

In the next phase, NMN, apigenin, and their combination were administered to cells subjected to oxidative stress-induced senescence. Individually, NMN slightly increased NAD+ levels in the treated cells, while apigenin showed a slightly more pronounced effect. However, the combination, N + A, produced a robust response, restoring NAD+ levels nearly to those observed in control cells that had not undergone senescence.

Further analysis revealed that senescence elevated levels of the pro-inflammatory chemokine CXCL8; while NMN did little to mitigate this elevation, apigenin demonstrated efficacy in reducing it. The combination treatment significantly normalized CXCL8 levels. In terms of DNA damage, both NMN and apigenin lowered γ-H2AX levels, but their combination provided even greater reductions. Additionally, N + A improved mitochondrial respiration, restoring ATP synthesis and fostering proper mitochondrial membrane potential.

Furthermore, N + A proved beneficial for cellular differentiation, with precursors of cartilage, bone, and muscle tissues exhibiting upregulated differentiation markers following treatment.

Broad Benefits in Mice

The researchers extended their investigation to live mice, focusing on natural aging. Typically, with age, the muscles of mice visibly atrophy, senescent cells accumulate in musculoskeletal tissues, and fibrosis becomes apparent. The gait of these animals also suffers noticeable impairment. The results indicated that N + A administration mitigated these age-related effects, although not to the full extent observed in younger mice. Treated mice displayed increased voluntary movement and improved limb strength, and similarly to the cellular studies, the combination treatment was found to be superior to either NMN or apigenin administered alone.

The benefits observed in the study were found to be partially dependent on the sirtuin SIRT3. Aged mice genetically modified to lack SIRT3 exhibited significantly fewer advantages from N + A treatment relative to wild-type mice, in areas including senescence biomarkers, serum NAD+ levels, and muscle strength.

Additional Insights into Gut Health

Interestingly, N + A also conferred benefits to the gut. Treated wild-type mice demonstrated increased diversity in their gut microbiome. Furthermore, ferroptosis, a form of iron-induced cellular death, was reduced in the gut tissues of the mice receiving N + A treatment. Additionally, fecal bacteria from aged N + A treated mice displayed benefits when administered to untreated aged mice, akin to those from fecal bacteria derived from young mice. The intestinal metabolite phytosphingosine (PHS) was identified as a contributor to some of these benefits, warranting further investigation.

While the study reveals promising findings, it is important to note that these experiments were confined to cell cultures and mice. The potential side effects of administering a combination of NMN and apigenin in human subjects remain unknown. Nonetheless, the researchers posit that this “increasing income and reducing expenditure” approach offers “potential clinical translational value” for the restoration of muscle, cartilage, and bone tissue. Future studies involving larger animal models, and potentially human clinical trials, will be essential to validate the applicability of these findings.

Literature Cited

  • [1] Norheim, K. L., et al. (2024). Nature Aging, 4(12), 1772-1781.
  • [2] Yoshino, M., et al. (2021). Science, 372(6547), 1224-1229.
  • [3] Camacho-Pereira, J., et al. (2016). Cell Metabolism, 23(6), 1127-1139.
  • [4] Escande, C., et al. (2013). Diabetes, 62(4), 1084-1093.
  • [5] Wu, J., et al. (2022). The Journal of Clinical Investigation, 132(5).

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About the Author

Josh Conway

Josh has been writing and editing Lifespan articles over the past decade and is responsible for the continued production of daily news content. He has a programming background and is a long-time supporter of anti-aging medicine.

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