NAD+

One of the most fundamental molecules in biology. It falls by about half between your 20s and 50s.

Evidence: BHuman trials what's this?
Grade A biochemistry, Grade B that precursors and IV raise levels, Grade D for injected outcomes.
Also known as: Nicotinamide adenine dinucleotide
Class: Naturally occurring coenzyme; energy metabolism and sirtuin cofactor. Not a peptide.

The 30-second version

WhatThe coenzyme behind cellular energy, DNA repair and the sirtuin "longevity" enzymes.

Why people use itEnergy, mental clarity, recovery and healthspan, by IV or injection.

The honest catchRaising a number that falls with age isn’t the same as proven rejuvenation.

What it is

NAD+ is a helper molecule in every living cell, not a peptide, though it’s injected the same way and for similar goals. Levels drop by roughly half between your 20s and 50s, partly because a consuming enzyme called CD38 rises with age. That decline tracks much of what we call ageing, which is why restoring it is so appealing.

How it works

Energy. Carries electrons through the mitochondrial chain to make ATP.

DNA repair. PARP repair enzymes run on NAD+.

Sirtuins. SIRT1–7 need it; SIRT1 drives new mitochondria through PGC-1α.

Decline. CD38 rises with age and NAD+ falls, so all three systems slow.

Restore? More NAD+ should refuel all three. Whether injection does that in practice is the open question.

What the research shows

Tier 1, the biochemistry: textbook and undisputed¹. Tier 2, raising levels: nicotinamide riboside (NR) at 1,000 mg/day safely raised NAD+ in older adults¹. NMN at 250 mg/day raised NAD+ metabolites and improved muscle insulin sensitivity in prediabetic women². A single 750 mg IV infusion raised blood NAD+ several-fold³. Tier 3, injected outcomes: energy, longevity and recovery benefits from injection are largely unproven in controlled trials and rest on clinic experience. Restoring NAD+ reversed ageing biomarkers in animals.

Injection raises levels more directly, but oral precursors have the better controlled outcome data.

Evidence at a glance

Use	Grade	Best evidence	Main gap	Read
Biochemistry	AApproved	Central to energy, repair and sirtuins	—	Undisputed
Precursors raise NAD+	BHuman trials	NR and NMN raise levels; some benefit^1,2	Oral, not injected	Solid
IV raises NAD+	BHuman trials	Several-fold rise³	PK, not outcomes	Levels rise
Injected energy, longevity	DCommunity use	Clinic reports	No outcome trial	Largely subjective

Dosing: what has been reported

Not a recommendation. These figures describe what was studied or what circulates in practice, kept separate so you can see how solid each one is. Speak with a qualified clinician before acting on any of it.

Setting	Figure	Route	Grade
IV (clinic)	250–1,000 mg over 2–8 h; loading 250–500 mg/day for 3–5 days	IV infusion	C
Clinic injection	50–200 mg per injection, daily to several times weekly	SC / IM	D
Community, home	25–100 mg, daily to 2–3× weekly, in the morning	Subcutaneous	D
Oral precursors (comparison)	NR 300–1,000 mg/day; NMN 250–500 mg/day^1,2	Oral	B

Subcutaneous dosing gives steadier levels than IV peaks, which may suit sirtuins and PARPs better. Take it in the morning, because it’s energising.

Preparing & storing

NAD+ is relatively delicate and light-sensitive. Refrigerate once mixed, keep it in the dark and don’t shake it. Inject slowly, because it stings.

Reported side effects

Injection-site stinging or burning, often 5–15 minutes (the signature effect)
IV: chest tightness, flushing, nausea or cramping if infused too fast. These depend on the rate, not allergy.
Mild flushing, redness or bruising
Occasional GI upset; poor sleep if taken late

People who were genuinely depleted often notice energy and clarity within days. Healthy young people may notice little.

Who should avoid it

Active cancer without oncologist input: NAD+ fuels all fast-dividing cells
Pregnancy and breastfeeding
IV protocols should be supervised

Regulatory status checked Oct 2026

Body	Status	Detail
FDA (US)	Not approved as therapy	Sold as supplement or compounded.
EMA (EU)	Not approved as therapy	Supplements available.
CDSCO (India)	Not approved as therapy	Supplements available.
WADA	Not prohibited	IV infusions over 100 mL per 12 h breach the infusion rule.

The NexGen read

Sound biology, unproven payoff

NAD+ is one of the safest compounds in this guide, and its rationale is as strong as any. Whether injecting it delivers more than precursors do, or anything measurable beyond feeling better, hasn’t been shown. It helps most when you’re actually depleted.

References

Martens CR, Denman BA, Mazzo MR, et al. Chronic nicotinamide riboside supplementation elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9(1):1286.
Yoshino M, Yoshino J, Kayser BD, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021;372(6547):1224–1229.
Grant R, Berg J, Mestayer R, et al. Changes in the human plasma and urine NAD+ metabolome during a 6-hour IV infusion of NAD+. Front Aging Neurosci. 2019;11:257.