Nicotinamide as an Early Alzheimer's Disease Treatment

Inclusion Criteria:

1. Mild Cognitive Impairment (MCI) or dementia due to Alzheimer's disease (AD)
2. Biomarker criteria: Cerebral Spinal Fluid (CSF) Amyloid Beta 1-42 (Aβ42) <= 600 pg/mL, or A ratio of totaltau to Aβ42 ≥ 0.39.
3. Mini-Mental State Exam (MMSE) ≥ 20
4. Blood laboratories, urinalysis, and electrocardiogram are within normal limits ordeemed clinically not significant by the site investigator
5. Stable medications (including approved AD therapies) for at least 4 weeks
6. At least 6 years of education
7. Able to swallow oral tablets
8. Speaks English fluently
9. Available qualified study partner (≥3 times per week in-person communication with theparticipant)

Exclusion Criteria:

1. Active neurological or psychiatric diagnosis other than AD that may affect cognitionand/or function. (Obstructive sleep apnea is permitted, if treated.)
2. Inability to undergo lumbar puncture, including use of Coumadin, novel oralanticoagulants, clopidogrel, or dipyridamole. Use of aspirin <= 325mg daily ispermitted.
3. Hachinski ischemic scale > 4
4. Magnetic Resonance Imaging (MRI) incompatibility
5. MRI evidence of cortical stroke >1cm, superficial siderosis, or extensive white matterhyperintensity (Cardiovascular Health Study score 7-8+)
6. Diagnosis of cancer in the previous 5 years (with the exception of basal or squamouscell carcinoma)
7. Geriatric Depression Scale (GDS) score >6
8. History within the past 5 years of alcohol or substance use disorder
9. Laboratory evidence of a clinically significant abnormality that may interfere withstudy assessments
10. Active partial or total malabsorptive disease (e.g., celiac disease)
11. Resides in a skilled nursing facility
12. Participation in a clinical trial of a potential disease-modifying therapy for AD inprevious 6-months (time between last investigational drug administration and baselinefor the current study)
13. Pregnant, lactating or of child bearing potential (that is, women must be 2 yearspost-menopausal or surgically sterile to be considered not child bearing potential).
14. Unwillingness to abstain from over-the-counter nicotinamide for the duration of thetrial