A plain-language, continually updated guide from Dr. Matt Chalmers’ clinical reference on hormones and peptides.
NAD+ (nicotinamide adenine dinucleotide) is a molecule every one of your cells absolutely requires — it’s essential for turning food into usable cellular energy (ATP) and for powering the enzymes responsible for DNA repair, metabolism, and immune function. NAD+ levels decline as you age, which is the basic reason there’s so much interest in restoring it. You’ll see it delivered several different ways: oral precursors (NMN and NR), IV infusion of NAD+ itself, IV infusion of NR, subcutaneous injection, and even intranasal application (though that last route has limited human data).
This is the single most important thing to understand about NAD+ therapy, and it’s genuinely underappreciated: the evidence base differs sharply depending on how it’s delivered. NAD+ itself is a large, charged molecule that can’t easily cross into your cells directly — so raising it in your bloodstream via IV doesn’t automatically translate into raising it inside your cells the way oral precursor supplements do (since your cells actively take those up and convert them internally).
Oral precursors have the strongest human evidence by far. In clinical trials, oral NR at 1,000 mg per day raised NAD+ levels in blood cells by roughly 60% after 6 weeks, and 3,000 mg per day produced roughly a 5-fold increase after 10 weeks — with good safety and tolerability at these doses. Oral NMN has multiple human randomized trials showing improved physical performance measures as well.
Direct IV NAD+ infusion, by contrast, has much more limited controlled human data, and what exists suggests a real tolerability tradeoff: a 2026 study comparing IV NAD+ to IV NR found NAD+ infusions caused more nausea, malaise, sweating, stomach cramping, and headache, and took meaningfully longer to complete. If you’re specifically comparing routes, that’s a genuinely useful, hard-to-find piece of information.
Niacin (vitamin B3) is the direct dietary precursor your body uses to build NAD+ naturally, which is why NMN and NR (both niacin-family molecules) work as effective oral precursors in the first place. Riboflavin (B2) also supports NAD+-dependent enzyme function in the electron transport chain, and magnesium is required for the ATP-producing reactions NAD+ ultimately powers.
NAD+ is not FDA-approved for any indication. NMN and NR are legally available as over-the-counter dietary supplements in the U.S. Injectable NR chloride has been under FDA 503B Bulk Drug Substances Category 1 evaluation since December 2022. IV and subcutaneous NAD+ administration should only be done under medical supervision given its documented reaction profile. This page describes research findings only and is not a claim about effects in humans or an offer to treat any condition.
Oral NMN or NR currently has stronger human evidence than IV NAD+ for reliably raising NAD+ levels in the blood.
NAD+ is a vital coenzyme that powers cellular energy production by carrying electrons in metabolism. It is also used by enzymes such as sirtuins and PARPs that support DNA repair, gene regulation and stress resistance. Levels decline with age mainly because more of it gets used up, by CD38 (driven by chronic inflammation) and PARPs (activated by DNA damage), while the body makes less of it. This drop is linked to mitochondrial dysfunction and other aging-related problems, though the amount varies by tissue.
The main difference is how much NAD+ reaches the bloodstream at once. IV puts NAD+ directly into a vein over a slow infusion (typically 1 to 4 hours), so all of it is available right away and larger single doses are possible. Injections (usually into muscle or under the skin) place a smaller amount into tissue, where it is absorbed more gradually over minutes to hours.
NAD+ precursors (mainly oral NMN or NR) reliably raise NAD+ levels in the blood, but human research is lacking on how much that improves brain fog or energy. Clinically, many people report a boost in energy and mental clarity.
IV NAD+ commonly causes infusion reactions that depend on how fast it is given. They are usually temporary and go away when the drip is slowed or stopped.
Yes. We offer the injectable version.
This page draws on The Pillars Path: A Root-Cause Guide to Hormones, Peptides, and Metabolic Health by Dr. Matt Chalmers — Pillars of Wellness’ clinical reference on hormone and peptide therapy.
