Melatonin, vitamin B6 (pyridoxine), and niacin (vitamin B3) can indeed work synergistically to support brain function and overall well-being. Here’s how these nutrients interact and benefit each other in the brain:

### Melatonin

- **Function**: Melatonin regulates sleep-wake cycles and is synthesized in the brain from serotonin, which is derived from tryptophan.

- **Role in the Brain**: It promotes sleep, which is essential for cognitive functions, memory consolidation, and overall mental well-being.

### Vitamin B6 (Pyridoxine)

- **Function**: Vitamin B6 is crucial for the synthesis of neurotransmitters like serotonin, dopamine, and GABA. It also helps convert tryptophan to serotonin and niacin.

- **Role in the Brain**: By supporting neurotransmitter production, B6 aids in mood regulation, cognitive function, and overall mental health. It helps reduce symptoms of depression and anxiety by maintaining proper brain function [[❞]](https://verybigbrain.com/nootropics/vitamin-b6-and-the-mind-from-neurotransmitters-to-neuroprotection/) [[❞]](https://naturopathiccurrents.com/ca/articles/vitamin-b6-tryptophan-and-other-serotonin-and-gaba-influencers).

### Niacin (Vitamin B3)

- **Function**: Niacin is vital for cellular energy production, DNA repair, and synthesis.

- **Role in the Brain**: It maintains brain cell health by providing the energy needed for optimal brain function. Adequate niacin levels support cognitive functions and protect against neurodegenerative diseases [[❞]](https://www.mdpi.com/2072-6643/8/2/68).

### Synergistic Effects

1. **Neurotransmitter Synthesis**:

- Vitamin B6 is essential for converting tryptophan to serotonin, which can then be converted to melatonin. Adequate B6 ensures sufficient serotonin is available for melatonin production, enhancing sleep quality [[❞]](https://verybigbrain.com/nootropics/vitamin-b6-and-the-mind-from-neurotransmitters-to-neuroprotection/) [[❞]](https://naturopathiccurrents.com/ca/articles/vitamin-b6-tryptophan-and-other-serotonin-and-gaba-influencers).

2. **Sleep and Mood Regulation**:

- Melatonin promotes sleep, vital for cognitive function and mental health. B6 and niacin support neurotransmitter balance, enhancing mood and cognitive function, further promoting restful sleep [[❞]](https://www.mdpi.com/2072-6643/8/2/68) [[❞]](https://naturopathiccurrents.com/ca/articles/vitamin-b6-tryptophan-and-other-serotonin-and-gaba-influencers).

3. **Energy and Cellular Health**:

- Niacin supports energy production in brain cells, necessary for synthesizing and regulating neurotransmitters influenced by B6. This energy support helps maintain healthy brain cell function [[❞]](https://www.mdpi.com/2072-6643/8/2/68).

In conclusion, melatonin, B6, and niacin can work together to support brain health by improving sleep, enhancing neurotransmitter production, and ensuring optimal cellular function. This synergistic effect may lead to better cognitive function, mood regulation, and overall mental well-being. For personalized advice, it is always best to consult with a healthcare provider to determine the appropriate combination and dosages for your specific needs.