A form of vitamin B3 that reliably raises the cell-energy molecule it targets. What follows is thin: longer walking distance in narrowed leg arteries, slight motor gains in early Parkinson's disease, no gain in strength or walking speed in older adults. Side effects mild. Much research is funded by sellers. Recent work questions the reason for taking it. (Full Review)

Protocol

Standard dose

250–300 mg once daily

Nicotinamide riboside chloride; the dose at which whole-blood NAD+ rises about 50% within two weeks

Best time of day

Morning, with food

NAD+ synthesis peaks early; food reduces the nausea reported at gram doses

Research dose range

300–2000 mg daily

6–24 weeks in trials; above 1000 mg no additional functional benefit has been demonstrated

Time to effect

Walking distance

6 months

The walking-distance result in peripheral artery disease

Airway inflammation

6 weeks

The lung-inflammation result in obstructive lung disease

Blood NAD+

2 weeks

Rises then plateaus; no functional outcome has appeared that quickly

Benefits

Medium: Walking distance in peripheral artery disease; motor symptom scores in early Parkinson's disease

Low: Systolic blood pressure and arterial stiffness; body composition and resting energy expenditure

Speculative: Whole-blood and tissue NAD+ availability; circulating and airway inflammatory markers; neuronal markers of neurodegenerative pathology; reduced epigenetic age and senescence markers; lifespan extension

Contraindications

Active malignancy, measurable residual disease, or cancer treated within the past 5 years

Receiving a PARP inhibitor, an investigational NAMPT inhibitor, or cytotoxic chemotherapy

Pregnant and lactating women

Children and adolescents under 18 years

Severe hepatic impairment (Child-Pugh Class B or C)

Advanced kidney disease (estimated glomerular filtration rate below 30 mL/min/1.73 m²)

Known hypersensitivity to niacin or nicotinamide

Key Interactions

Radiotherapy

Antihypertensive medication (amlodipine, lisinopril, losartan)

Levodopa/carbidopa

Other vitamin B3 supplements (niacin, nicotinamide, nicotinamide mononucleotide, NADH)

Over-the-counter multivitamins, fortified cereals and energy drinks

Methyl-donor supplements (trimethylglycine, methylfolate, vitamin B12)

Sirtuin-activating supplements (pterostilbene, resveratrol)

CD38-inhibiting flavonoids (apigenin, quercetin)

Alcohol

Prolonged fasting and endurance exercise

Risk & Side Effects

High: Mild gastrointestinal, flushing and skin adverse events

Medium: Decline in timed physical performance in mild cognitive impairment

Low: Rising plasma homocysteine at high doses; niacin-equivalent intake above the tolerable upper limit; reduced cerebral blood flow in default-mode regions; rising plasma glucose

Speculative: Promotion of existing or occult cancer; interference with treatments that rely on NAD+ depletion

Monitoring

Marker	Target	Why
Whole-blood nicotinamide adenine dinucleotide	No established target; track change from own baseline, 40–150% rise typical	Confirms absorption and conversion
Homocysteine	5–8 µmol/L	Detects methyl-group drain from clearing surplus nicotinamide
High-sensitivity C-reactive protein	Below 1.0 mg/L	Tracks the inflammation signal the supplement is proposed to lower
Alanine aminotransferase	Below 25 U/L in men, below 20 U/L in women	Screens for liver strain from cumulative vitamin B3 load
Glycated haemoglobin	4.8–5.4%	NAD+ precursors as a class have been linked to higher plasma glucose
Fasting glucose	75–90 mg/dL	Same concern as above, with faster feedback between visits
Systolic and diastolic blood pressure	Below 120/80 mmHg	The only cardiovascular signal produced in a controlled trial
Prostate-specific antigen, men over 45	Below 1.0 ng/mL under age 50; below 2.0 ng/mL at age 60	The only practical screen bearing on the theoretical tumour-promotion concern

Cadence: Baseline before the first dose, repeated at 8–12 weeks, then at 6 months and every 6–12 months thereafter. Blood pressure monthly for the first three months in anyone starting above 120 mmHg systolic; homocysteine and liver enzymes 4 weeks after any increase above 1000 mg daily.

Qualitative Assessment

Walking capacity — distance covered in six minutes, or time to onset of calf pain, retested every 3 months
Perceived daytime energy and afternoon fatigue, scored 1–10 each evening for a week before and after starting
Sleep quality and dream vividness, particularly in anyone dosing later than midday
Cognitive clarity and word-finding, judged against a fixed weekly task rather than general impression
Recovery from hard exercise sessions, measured as days to return to baseline soreness

Nicotinamide Riboside for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment