What is the recommended dose of Nicotinamide (Niacinamide) for dementia prevention?

Nicotinamide for Dementia Prevention: Not Recommended

There is no established dose of nicotinamide for dementia prevention, and current evidence does not support its use for this purpose. Major clinical guidelines do not recommend nicotinamide supplementation to prevent or treat cognitive decline in dementia 1, 2.

Evidence Against Nicotinamide for Dementia Prevention

Clinical Trial Results

The most recent and highest quality evidence comes from a 2025 phase 2a randomized controlled trial that tested nicotinamide 1,500 mg twice daily (3,000 mg total daily dose) for 48 weeks in patients with mild cognitive impairment or mild dementia 3. This study found:

• No significant reduction in CSF p-tau231 (the primary outcome; p = 0.61) 3
• No significant effects on secondary biomarkers including CSF p-tau181, total tau, or amyloid beta (all p > 0.05) 3
• No significant improvement in cognitive function (ADAS-cog) or activities of daily living 3
• Only a modest, unadjusted benefit on CDR-SB that did not survive correction for multiple comparisons 3

Critical Pharmacokinetic Limitations

A 2025 pharmacokinetic analysis of the same trial revealed fundamental problems with oral nicotinamide delivery 4:

• CSF nicotinamide was measurable in only 32% of participants despite massive plasma increases (>130-fold) 4
• 57% of participants had extensive metabolic inactivation to methyl-nicotinamide in the CSF, rendering the drug ineffective 4
• Only the 6 participants with elevated CSF nicotinamide showed a 34% decrease in pTau231, but this represents a small minority 4
• The blood-brain barrier penetration and rapid methylation make oral nicotinamide unreliable for CNS effects 4

Historical Evidence

An earlier 2000 study using oral NADH 10 mg/day for 3 months found no evidence for cognitive improvement in 19 patients with mild to moderate dementia 5.

Guideline-Recommended Approaches

For Dementia Treatment (Not Prevention)

FDA-approved cholinesterase inhibitors are the standard of care for mild to moderate dementia 1, 2, 6:

• Donepezil: 5 mg daily, increased to 10 mg after 4-6 weeks 6
• Rivastigmine: 1.5 mg twice daily, titrated to 6-12 mg daily 6
• Galantamine: 4 mg twice daily with meals, increased to 8-12 mg twice daily 6
• Memantine: For moderate to severe dementia 2

For Actual Niacin Deficiency (Pellagra)

If there is documented niacin deficiency causing the classic triad of diarrhea, dermatitis, and dementia (pellagra), treatment doses are 1:

• Nicotinamide 300 mg/day for traditional pellagra 1
• Nicotinic acid 15-20 mg/day as an alternative 1
• These doses are for treating deficiency, not for dementia prevention in non-deficient individuals 1

Common Pitfalls to Avoid

• Do not use non-FDA approved supplements like nicotinamide instead of evidence-based treatments for diagnosed cognitive disorders 6
• Do not confuse treatment of pellagra-related dementia (a reversible cause from severe niacin deficiency) with prevention or treatment of Alzheimer's disease or other neurodegenerative dementias 1
• Do not assume that because nicotinamide is a vitamin, higher doses are safe or beneficial - the upper limit for nicotinamide is 900 mg/day for adults, and doses of 3,000 mg/day used in trials far exceed this 1
• Do not overlook that nicotinamide at 3 g/day can cause hepatotoxicity ranging from elevated liver enzymes to acute liver failure 1

What Actually Works for Dementia Risk Reduction

Evidence-based interventions for reducing dementia risk include 2:

• Physical activity: Aerobic exercise and resistance training 2
• Mediterranean diet: High in mono- and polyunsaturated fatty acids, low in saturated fats 2
• Hearing loss treatment: Audiologic rehabilitation when indicated 2
• Cardiovascular risk factor management: Blood pressure control, diabetes management 2
• Cognitive engagement: Ongoing educational experiences and cognitively stimulating activities 2
• Social engagement: Throughout the life course 2