Recent studies have investigated the potential synergistic effects of green tea extract, particularly its active component epigallocatechin gallate (EGCG), in combination with nicotinamide, a form of vitamin B3. This combination has garnered attention for its possible benefits in enhancing neuronal health and combating neurodegenerative diseases, particularly Alzheimer’s disease.

Study Overview

A pivotal study conducted by researchers at the University of California, Irvine, published in August 2025 in the journal GeroScience, explored the effects of nicotinamide and EGCG on aging neurons. The primary objective was to assess how these compounds could restore energy levels and improve the brain’s ability to clear toxic proteins associated with neurodegenerative conditions.

Key Findings

1. Restoration of Energy Levels:

• The study revealed that aging brain cells experience a significant decline in guanosine triphosphate (GTP) levels, a crucial energy molecule necessary for various cellular functions, including autophagy (the process of clearing cellular waste).
• Treatment with nicotinamide and EGCG for just 16 hours restored GTP levels in aged neurons to levels comparable to those found in younger cells.

1. Enhancement of Cleanup Functions:

• The combination treatment activated autophagy-related pathways, significantly improving the neurons’ ability to clear amyloid-beta aggregates, which are toxic proteins linked to Alzheimer’s disease.
• Additionally, the treatment reduced markers of oxidative stress, further supporting neuronal health and resilience.

1. Increased Neuronal Survival:

• The study reported a 22% improvement in cell survival among aged neurons treated with the combination of nicotinamide and EGCG, indicating enhanced neuronal viability.

1. Mechanism of Action:

• Nicotinamide was found to boost levels of NAD+ (nicotinamide adenine dinucleotide), a critical molecule that supports cellular metabolism and is a precursor for GTP production.
• EGCG was shown to activate Nrf2, a transcription factor that regulates antioxidant genes, providing protective effects against oxidative damage.

Implications for Alzheimer’s Disease

The findings from this study suggest that the combination of nicotinamide and EGCG may offer a promising non-pharmaceutical approach to combat age-related cognitive decline and Alzheimer’s disease. By restoring energy levels and enhancing the brain’s natural cleanup mechanisms, this treatment could potentially mitigate some of the detrimental effects of aging on brain function.

Limitations and Future Research

While the results are promising, it is important to note that the study was conducted using lab-grown neurons from mice. Further research is needed to confirm these effects in live animal models and human subjects. Additionally, previous clinical trials have indicated that oral nicotinamide may not be effective due to its inactivation in the bloodstream, highlighting the need for optimized delivery methods to enhance bioavailability.

Conclusion

The combination of green tea extract (EGCG) and vitamin B3 (nicotinamide) has shown significant potential in restoring energy levels and enhancing the cleanup functions of aging brain cells. This research opens new avenues for dietary or non-pharmaceutical interventions aimed at addressing neurodegenerative diseases, particularly Alzheimer’s disease.

Citation: Santana, R. A., Brewer, G., et al. (2025). “Treatment of age-related decreases in GTP levels restores endocytosis and autophagy.” GeroScience. DOI: 10.1007/s11357-025-01786-4.