Emerging evidence · Grade B
NAD+
NAD+ (Nicotinamide Adenine Dinucleotide)
Score
64 / 100
Type
Coenzyme (not a peptide)
Delivery
Precursors / IV
Status
Supplement; benefit unproven
TL;DR
01
NAD+ is a coenzyme (not a peptide) essential to energy metabolism, DNA repair, and sirtuin signaling; its levels fall with age.
02
The anti-aging rationale is strong in the lab: restoring NAD+ slows or reverses several age-related problems in animal models.
03
In humans, oral precursors (nicotinamide riboside, NMN) reliably and safely raise blood NAD+ levels — that part is proven.
04
But raising the level is a biomarker, not a demonstrated clinical benefit: human trials have largely not shown the functional or longevity payoffs the marketing implies.
05
Injectable/IV NAD+ is popular but its cell-level bioavailability is questionable, and much of the human data comes from industry-funded studies.
Precursors raise NAD+
Yes (proven)
+40–90% in human RCT
Clinical outcome benefit
Unproven
biomarker ≠ benefit
IV NAD+ bioavailability
Questionable
large, poorly cell-permeant
Evidence bias
Often industry-funded
level-raising studies
Age decline
Real
NAD+ falls with age
Part 01 · How it works
Mechanism.
NAD+ is a molecule every cell uses to make energy and run repair and signaling enzymes like sirtuins. Its levels drop as we age, and in animals topping it back up can slow age-related decline — a genuinely exciting idea. In people, taking precursor vitamins (nicotinamide riboside, NMN) does reliably raise blood NAD+, and it's safe. The gap is between 'the level went up' and 'you're healthier or living longer' — human trials have mostly not shown those downstream benefits yet. And injecting NAD+ directly (IV drips) faces a basic problem: the molecule is large and doesn't easily get into cells.
Refilling a tank that empties with age. In animals a full tank helps; in humans we can prove supplements refill it, but not yet that the refill makes the engine run better or longer.
Redox + enzyme cofactor
Central to energy metabolism and a cofactor for sirtuins, CD38, and PARPs (DNA repair).
Age-related decline
Tissue and cellular NAD+ levels fall with age across model organisms and humans.
Precursor repletion
Oral NR/NMN raise blood NAD+ dose-dependently and safely in human RCTs.
Benefit gap
Whether repletion yields clinical benefit in humans is not established; IV NAD+ bioavailability is questionable.
Part 02 · Dosing & administration
How it's taken.
Community-reported · unregulatedValues below reflect commonly reported community protocols for NAD+. These are anecdotal and unregulated — not clinically validated and not a recommendation. Provided for educational purposes only — this is not medical advice and not instructions for self-administration. Consult your healthcare provider before making any health decision.
Supplement
Precursors (NR/NMN)
Oral precursors are the evidence-backed way to raise NAD+; IV NAD+ dosing is not outcome-validated.
·
Any doses referenced are from supplement studies, not medical instructions.
·
Oral precursors (NR/NMN) reliably raise NAD+; IV NAD+ delivery is mechanistically questionable.
·
NAD+ is a coenzyme, not a peptide — included here as a longevity-category reference.
Need help with reconstitution?
Use the free peptide calculator for dilution, unit conversion, and injection volume.
Part 03 · Safety
Side effects, rare serious events, who shouldn't.
Common
GI upset (precursors)
Generally mild with NR/NMN.
Occasional
Flushing (high-dose niacin forms)
More with nicotinic acid than NR/NMN.
Form-dependent
Infusion discomfort (IV)
IV NAD+ drips often cause chest tightness/nausea if run fast.
Common
Serious · rare
Long-term outcome/safety
Long-term human benefit and safety of sustained repletion not established.
Uncertain
Unregulated IV settings
IV NAD+ is often given in unregulated wellness settings.
Setting-dependent
Absolute · do not use
×
Known hypersensitivity to NAD+ or any component
×
Active malignancy (NAD+ supports cancer cell metabolism; theoretical concern)
×
Pregnancy or breastfeeding
×
Gout (NAD+ metabolism may increase uric acid levels)
Relative · discuss first
!
Expecting proven anti-aging/longevity benefit — not demonstrated in humans
!
Relying on IV NAD+ for cellular repletion — bioavailability is questionable
!
Pregnancy or breastfeeding — insufficient data
!
Active malignancy — NAD+ metabolism and cancer interactions are complex; discuss with oncology
Interactions
Chemotherapy agents
NAD+ supports DNA repair which may reduce efficacy of DNA-damaging chemotherapy
Major
Alcohol
Alcohol depletes NAD+; supplementation may alter alcohol metabolism but does not protect against liver damage
Minor
PARP inhibitors (olaparib)
PARP inhibitors rely on NAD+ depletion in cancer cells; NAD+ supplementation may oppose their mechanism
Major
Niacin (vitamin B3)
Both increase NAD+ levels; additive flushing and potential liver stress at high doses
Minor
Labs to monitor
CMP (Comprehensive Metabolic Panel)
Baseline and every 3 months
Liver and kidney function during IV NAD+ therapy
CBC with Differential
Baseline and every 6 months
General safety monitoring
Uric Acid
Baseline and at 4 weeks
NAD+ metabolism produces uric acid as byproduct
Fasting Glucose & Insulin
Baseline and every 3 months
NAD+ and sirtuins affect glucose metabolism
Part 04 · Evidence
How strong is the evidence?
64
Grade B
Grade B, Emerging. A strong mechanistic and preclinical case, and human proof that precursors raise NAD+ safely — but the crucial step, demonstrating clinical benefit in humans, is missing, and IV delivery has a bioavailability problem.
Mechanistic plausibility
Central, well-understood coenzyme with a robust aging rationale.
85
Human evidence (biomarker)
RCTs confirm precursors raise NAD+ safely.
72
Outcome benefit
Human clinical/functional/longevity benefits largely unproven to date.
48
Delivery / bioavailability
Precursors work orally; direct IV NAD+ bioavailability into cells is questionable.
55
Independence
Several level-raising trials are industry-funded; independent outcome data limited.
58
Part 05 · Research log
Every study we cite.
We list each study with its methodology, funding source, and our quality grade. Flagged studies aren't dismissed — they're tagged so you can weigh them.
01
2017
NPJ Aging Mech Dis Industry funded
Repeat-dose NR + pterostilbene raises NAD+ in humans (RCT)
The precursor combination raised whole-blood NAD+ dose-dependently (~40% at 1X, ~90% at 2X) and was safe — proving human NAD+ repletion, but measuring the biomarker, not clinical outcomes.
Randomized, double-blind, placebo-controlled, 8 wk · n = 120 · Industry-sponsored; endpoint was NAD+ level, not a health outcome.
PMID 29184669 ↗
Moderate
02
2020
Nat Rev Mol Cell Biol Flagged
NAD+ metabolism and its roles in ageing (review)
Summarizes the strong preclinical case for NAD+ repletion in aging while explicitly noting that whether repletion is safe and beneficial in ageing humans remains to be established.
Narrative review · Independent review; candid about the human evidence gap.
PMID 33353981 ↗
High (review)
Evidence against
What didn't work, and where the evidence is thin.
Every publication is incentivized to tell you a peptide works. We catalogue the null results, failed trials, and mechanism limits we found in the same literature — so you can weigh them against the upside, with your provider.
01
Raising NAD+ is a biomarker, not a proven clinical benefit
Mechanism limit NPJ Aging Mech Dis · 2017
Human trials show precursors raise NAD+ levels, but that is the endpoint — they do not establish improvements in function, disease, or lifespan. Independent reviews explicitly flag this gap.
What this means: A higher NAD+ number on a blood test is not the same as being healthier. The marketed anti-aging benefits are not yet demonstrated in people.
PMID 29184669 ↗
02
IV NAD+ bioavailability is questionable, and evidence is industry-tilted
Mechanism limit Nat Rev Mol Cell Biol · 2020
NAD+ is a large molecule that does not readily enter cells, casting doubt on injectable/IV NAD+ 'drips'; meanwhile much of the level-raising human data comes from industry-funded studies.
What this means: The popular IV route is the least mechanistically supported, and the enthusiasm outpaces independent outcome evidence.
PMID 33353981 ↗
Part 06 · Cost & access
Where it's available, at what price.
United States
Supplement / clinic
Oral precursors (NR/NMN) sold as supplements; IV NAD+ offered in wellness clinics. Not an approved drug for aging.
Supplement to clinic-priced IV
European Union
Supplement (varies)
Precursor availability varies by country; IV in some clinics.
Varies
United Kingdom
Supplement (varies)
Precursors available; IV in private clinics.
Varies
Canada
Supplement (varies)
Precursors available; IV in some clinics.
Varies
The Peptide Column takes no affiliate commission from any source. NAD+ precursors are sold as supplements and IV NAD+ in wellness clinics; neither is an approved anti-aging treatment, and human clinical benefit is unproven. We link only to clinician-directed care, never to sellers.
Part 07 · Your appointment
Questions to bring.
01
Should I pursue IV NAD+ or oral precursors (NMN/NR), and what are the trade-offs?
02
What are my current NAD+ levels and how can they be tested?
03
How does NAD+ supplementation interact with cancer biology?
04
What dosing protocol and duration is supported by the evidence?
References
Every citation, numbered.
Citation list. For our editorial read of each study — including bias flags and quality grades — see the Research log above.
- 01. Repeat-dose NR + pterostilbene raises NAD+ in humans (RCT) · NPJ Aging Mech Dis, 2017 · PMID 29184669 ↗
- 02.
- 03. PubMed. NAD+ ageing review and precursor RCT