NAD+

What NAD+ Does

NAD+ (nicotinamide adenine dinucleotide) is not a peptide — it is a coenzyme found in every living cell. It sits at the center of cellular energy production and repair, serving as an essential substrate for over 500 enzymatic reactions. Without adequate NAD+, cells cannot produce energy efficiently, repair damaged DNA, or maintain the epigenetic patterns that keep genes properly regulated. The decline of NAD+ with age is now considered one of the fundamental drivers of aging itself.

The mechanisms that matter:

• Sirtuin activation (SIRT1-7) — sirtuins are a family of seven NAD+-dependent deacetylase enzymes that regulate gene expression, DNA repair, mitochondrial biogenesis, inflammation, and cellular stress resistance. SIRT1 (the most studied) controls metabolic adaptation, fat metabolism, and insulin sensitivity. SIRT3 governs mitochondrial function. SIRT6 protects genomic stability. All seven require NAD+ as a co-substrate — when NAD+ drops, sirtuin activity drops with it
• DNA repair via PARP enzymes — poly(ADP-ribose) polymerases (PARP1 and PARP2) consume NAD+ to repair single-strand DNA breaks. As DNA damage accumulates with age and environmental exposure, PARP enzymes consume more NAD+, creating a vicious cycle: more damage leads to more NAD+ consumption, leaving less NAD+ for sirtuins and energy production
• Mitochondrial electron transport — NAD+ and its reduced form NADH are the primary electron carriers in oxidative phosphorylation, the process that generates ATP (cellular energy) in mitochondria. Depleted NAD+ directly impairs energy production at the cellular level
• CD38 and age-related decline — CD38 is an ectoenzyme (NADase) that degrades NAD+. CD38 expression increases with age, driven by chronic low-grade inflammation (inflammaging). This is the primary reason NAD+ declines approximately 50% between ages 40 and 60. Inhibiting CD38 (with compounds like apigenin or quercetin) is a complementary strategy to boosting NAD+ directly
• Circadian rhythm regulation — NAD+ oscillates in a circadian pattern, peaking during active hours. SIRT1 and NAMPT (the rate-limiting enzyme in NAD+ salvage synthesis) are both clock-controlled genes. Age-related NAD+ decline disrupts circadian rhythm, contributing to the sleep fragmentation and metabolic dysregulation seen in aging

NAD+ Delivery Methods Compared

The biggest decision is how to get NAD+ into your cells. Each route has fundamentally different pharmacokinetics:

Feature	IV NAD+	SubQ NAD+	Oral NMN	Oral NR
Bioavailability	~100% (direct to blood)	High (bypasses GI)	Variable (30-50% estimated)	Variable (30-50% estimated)
Peak NAD+ increase	Immediate, dramatic	1-2 hours	2-4 hours	2-4 hours
Typical dose	250-500 mg/session	100-500 mg/day	500-1,000 mg/day	300-1,000 mg/day
Convenience	Low (2-4 hr infusion)	Moderate (daily injection)	High (capsule)	High (capsule)
Flushing/nausea	Common, can be severe	Mild at injection site	Rare	Rare
Cost	$250-750/session	$3-10/day	$1-3/day	$1-2/day
Evidence quality	Clinical case series	Emerging	Growing (Sinclair lab data)	Multiple human RCTs
Best for	Acute recovery, initial loading	Daily maintenance (committed users)	Daily maintenance (convenience)	Daily maintenance (evidence-based)

Peter Attia’s perspective: Attia has discussed NAD+ on The Drive podcast, noting that while the biology of NAD+ decline is compelling, the clinical evidence for NAD+ supplementation improving hard outcomes (disease incidence, lifespan) in humans remains limited. He views NAD+ precursors as reasonable but emphasizes that exercise, sleep, and nutrition remain far more impactful for longevity than any supplement.

David Sinclair’s perspective: Sinclair (Harvard Medical School) has been the most prominent scientific advocate for NMN supplementation, publishing extensively on NAD+ and sirtuin biology. His lab demonstrated that NMN restores NAD+ levels and improves metabolic function in aged mice. He publicly takes NMN daily. His 2013 Cell paper showing NMN reversed aspects of aging in mice was a landmark moment for the field.

Dosing Protocol

Standard Protocol

Parameter	Detail
Route	IV infusion, subcutaneous injection, or oral precursor (NMN/NR)
IV dose	250–500 mg per session
IV frequency	1–2x per week (loading), then 1–2x per month (maintenance)
SubQ dose	100–500 mg per day
SubQ frequency	Once daily
Oral NMN dose	500–1,000 mg per day
Oral NR dose	300–1,000 mg per day
Cycle length	Ongoing — NAD+ decline is chronic, so supplementation is typically continuous
Best timing	Morning (aligns with circadian NAD+ peak)

Dose Tiers by Route

IV NAD+

Phase	Dose	Frequency	Duration
Loading	250–500 mg	2x per week	2–4 weeks
Maintenance	250–500 mg	1–2x per month	Ongoing
Intensive (addiction/neuro)	500–1,000 mg	Daily	7–10 days

IV loading phases are common at longevity clinics. After the initial loading period, most patients transition to monthly maintenance infusions or switch to SubQ/oral protocols for daily support.

SubQ NAD+

Protocol	Dose	Frequency
Starting	100 mg/day	Once daily
Standard	200–300 mg/day	Once daily
Aggressive	500 mg/day	Once daily

SubQ NAD+ has gained significant traction as a practical middle ground — higher bioavailability than oral precursors, dramatically more convenient than IV infusions. Inject subcutaneously into the abdomen or thigh. Mild stinging at the injection site is common and resolves quickly.

Oral Precursors (NMN / NR)

Precursor	Starting Dose	Standard Dose	Upper Range
NMN	250 mg/day	500 mg/day	1,000 mg/day
NR	300 mg/day	600 mg/day	1,000 mg/day

Take in the morning with or without food. Some protocols split the dose (morning and early afternoon) to maintain steadier NAD+ levels throughout the day. Do not take NMN or NR in the evening — the energizing effect can interfere with sleep.

Timing Guidance

• Morning dosing preferred — NAD+ levels naturally peak during active hours due to circadian regulation of NAMPT. Morning supplementation aligns with this biology
• With or without food — oral NMN/NR can be taken either way. Some data suggests sublingual NMN may have improved absorption
• IV infusions — schedule in the morning or early afternoon. The 2-4 hour infusion time plus potential fatigue afterward means evening infusions can disrupt sleep schedules
• SubQ injections — morning, consistent time daily

Reconstitution (SubQ NAD+)

SubQ NAD+ comes as lyophilized powder requiring reconstitution with bacteriostatic water.

For a 500 mg vial — add 2 mL bacteriostatic water:

Daily Dose	Volume to Draw
100 mg	20 units on insulin syringe
200 mg	40 units
250 mg	50 units
500 mg	100 units (1 mL)

Concentration: 250 mg/mL. A 500 mg vial lasts 2-5 days depending on dose.

Storage: Refrigerate at 2-8°C. Use within 28 days of reconstitution. NAD+ solution may develop a slight yellow tint — this is normal. Discard if it becomes cloudy or develops particulates.

Cycling

NAD+ supplementation is generally not cycled. The rationale: NAD+ decline is a chronic, progressive condition of aging. Intermittent supplementation would allow NAD+ levels to drop during off-periods, negating accumulated benefits. Most longevity practitioners recommend continuous, indefinite use — similar to how you would not cycle a vitamin deficiency correction.

Some practitioners recommend periodic IV loading “boosts” (a week of daily IV sessions every 6-12 months) on top of a daily oral or SubQ baseline protocol.

What to Expect

Week 1

• IV route: Noticeable energy improvement within hours of first infusion. Flushing and nausea during infusion are common. Mental clarity often reported the day after infusion
• SubQ route: Mild injection-site stinging. Energy effects subtle initially. No systemic side effects for most users
• Oral route: No immediate subjective effects for most users. NMN/NR takes time to meaningfully shift intracellular NAD+ levels

Weeks 2-4

• Energy and mental clarity — the most consistently reported benefit across all routes. Users describe it as “a fog lifting” or “getting back something they didn’t realize they’d lost”
• Sleep quality improvements — many users report deeper sleep and more restorative mornings, likely mediated by circadian rhythm and SIRT1 effects on melatonin regulation
• Exercise recovery — faster recovery from training sessions, reduced delayed-onset muscle soreness. Attributable to enhanced mitochondrial function and DNA repair capacity

Months 1-3

• Sustained energy — the initial energy boost normalizes into a new baseline. Users stop noticing the improvement because it becomes their default state
• Skin quality — some users report improved skin texture and reduced fine lines, likely mediated by SIRT1/SIRT6 effects on cellular turnover and collagen maintenance
• Metabolic markers — fasting glucose, insulin sensitivity, and lipid profiles may improve, particularly in metabolically unhealthy individuals

Months 3-12+

• Long-term cellular maintenance — the primary value of sustained NAD+ repletion is the prevention of age-related cellular decline rather than dramatic acute improvements
• Biomarker tracking — biological age clocks (GrimAge, PhenoAge, DunedinPACE) can potentially detect epigenetic changes over 6-12+ month timeframes, though evidence for NAD+ supplementation shifting these clocks in humans is still emerging

What the Research Says

NAD+ biology has one of the strongest preclinical evidence bases in aging research. Human data is growing but still limited for hard clinical endpoints.

NMN restores NAD+ and reverses aging markers in mice (Sinclair Lab, Harvard, 2013-2020): Multiple publications from David Sinclair’s laboratory demonstrated that NMN supplementation in aged mice restored NAD+ levels, improved mitochondrial function, enhanced insulin sensitivity, increased exercise endurance, and reversed vascular aging. The 2013 paper in Cell showing that one week of NMN treatment made the muscle of 22-month-old mice resemble that of 6-month-old mice was a watershed moment. These results are robust and replicated — the open question is translation to humans.

First human NMN trial (Igarashi et al., 2022, Science): A randomized controlled trial of NMN (250 mg/day for 12 weeks) in healthy older men showed significant increases in blood NAD+ levels and improvements in muscle insulin sensitivity and muscle remodeling. This was the first rigorous human trial confirming that oral NMN raises NAD+ in humans and produces measurable metabolic benefits. Published in Science.

NR human trials (Martens et al., 2018, Nature Communications): NR supplementation (1,000 mg/day for 6 weeks) in healthy middle-aged and older adults raised blood NAD+ metabolite levels by approximately 60%. Well-tolerated with no safety concerns. Limited evidence for functional improvements at this dose and duration.

CD38 as the driver of NAD+ decline (Camacho-Pereira et al., 2016, Cell Metabolism): This seminal paper demonstrated that CD38 — not reduced synthesis — is the primary cause of age-related NAD+ decline. CD38 expression increases with age driven by chronic inflammation, and CD38 knockout mice maintain youthful NAD+ levels. This shifted the field’s understanding and opened the door for CD38 inhibitor strategies alongside NAD+ supplementation.

NAD+ in addiction recovery (clinical observations): NAD+ IV therapy has been used in addiction medicine clinics (particularly by NAD Treatment Center and Springfield Wellness Center) for opioid and alcohol withdrawal support. These are clinical case series, not controlled trials, but report rapid reduction in withdrawal symptoms and cravings during 7-10 day high-dose IV NAD+ protocols (750-1,000 mg/day). Mechanistic rationale centers on restoring depleted NAD+ in neurons damaged by chronic substance use.

Key researchers and practitioners:

• David Sinclair (Harvard) — foundational NAD+/sirtuin research, public NMN advocate
• Charles Brenner (City of Hope) — discovered NR as an NAD+ precursor, leads NR clinical research
• Peter Attia — discusses NAD+ science on The Drive, cautious about overselling supplement-based longevity
• Andrew Huberman — has covered NAD+ biology on Huberman Lab, with emphasis on lifestyle factors (cold exposure, exercise) that naturally boost NAD+

Safety

Side Effects

Side Effect	Route	Frequency	Management
Flushing/chest pressure	IV	~60-80%	Slow infusion rate; resolves in minutes
Nausea/cramping	IV	~40-50%	Slow infusion rate; anti-nausea pre-treatment
Injection-site stinging	SubQ	~30%	Mild, transient; rotate injection sites
GI discomfort	Oral NMN/NR	~10-15%	Take with food; reduce dose
Headache	All routes	~5-10%	Stay hydrated; usually resolves day 1-2
Insomnia	Oral (evening dose)	~10-15%	Move dosing to morning
Anxiety/restlessness	IV (high dose)	~10%	Attributable to rapid energy increase; resolves in hours

Critical Warnings

IV infusion rate matters. Rapid IV NAD+ infusion causes severe chest tightness, nausea, cramping, and flushing. This is not an allergic reaction — it is a pharmacological effect of rapidly elevated NAD+ activating TRPV channels. The fix is always to slow the drip. Clinical settings use controlled infusion pumps. Never attempt to self-administer IV NAD+ outside a clinical setting.

Potential interaction with cancer biology. NAD+ fuels all cells, including cancerous ones. Some cancer cells upregulate NAD+ synthesis pathways. While there is no clinical evidence that NAD+ supplementation promotes cancer, individuals with active malignancies should consult their oncologist before supplementing. Sirtuins (particularly SIRT1) have both tumor-suppressive and tumor-promoting roles depending on cancer type and context.

NMN FDA regulatory status. The FDA’s 2022 determination that NMN cannot be marketed as a dietary supplement creates a regulatory gray zone. NMN products remain widely sold, but the long-term availability through supplement channels is uncertain. NR is not affected by this determination and remains a clearly legal dietary supplement.

Methyl donor depletion. NAD+ metabolism consumes methyl groups. High-dose, long-term NAD+ precursor supplementation may deplete methyl donors (SAM, folate, B12). Consider supplementing with methylated B vitamins (methylfolate, methylcobalamin) and TMG (trimethylglycine/betaine) when using high-dose NMN or NR. David Sinclair has publicly stated he takes TMG alongside NMN for this reason.

Do Not Use If

• Active cancer or undergoing cancer treatment (consult oncologist)
• Pregnant or breastfeeding (insufficient safety data)
• Under 18 (age-related NAD+ decline is not relevant)
• Taking medications that interact with NAD+ metabolism (certain chemotherapeutics, PARP inhibitors like olaparib)

What Comes Next

• Layer telomere support — Epitalon Protocol targets a complementary hallmark of aging (telomere attrition)
• Add mitochondrial support — MOTS-c Protocol directly targets mitochondrial function and metabolic health
• Explore immune longevity — Thymosin Alpha-1 Protocol supports thymic function and immune aging
• Use the Reconstitution Calculator for SubQ NAD+ dosing math