NAD IV therapy versus subcutaneous NAD+: what the evidence actually says

What it is

Nicotinamide adenine dinucleotide (NAD+) is the coenzyme every cell uses to move electrons in energy metabolism and that the sirtuin and PARP enzyme families consume to repair DNA and regulate gene expression. Tissue NAD+ levels fall with age in animals and, in the limited human data, in muscle and skin. The therapeutic idea is simple: put it back.

There are three ways clinics try. Oral precursors — nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) — which the body converts to NAD+. Intravenous NAD+, the molecule itself infused over several hours. And subcutaneous NAD+, small injections of the molecule under the skin, which is the form the NAD+ research page describes. The three are not interchangeable, and the evidence for each is very different.

What the research says

The honest picture: precursors have real trials with modest results, the IV has a single pharmacokinetic study and a reputation, and nobody has yet shown that pushing NAD+ into a healthy adult by any route changes an outcome that matters.

Protocols that are studied

• Intravenous. Clinics commonly run 250–1,000 mg in 500 ml saline over 2–6 hours; the only published study used 750 mg over six hours. Faster rates cause the reaction described below, so the drip time is set by tolerance, not by pharmacology.
• Subcutaneous. Typically 50–100 mg per injection, once to several times a week — the schedule, in milligrams and pen clicks, is on the NAD+ page. Not studied in a trial.
• Oral precursors. NR 300–1,000 mg/day or NMN 250–1,000 mg/day in the RCTs, for 6–12 weeks.
• Courses. IV packages are usually sold as 4–10 sessions over a few weeks; there is no data on repeat courses or on how long any effect persists.

Who it suits — and who should avoid it

The best candidates for any NAD+ route are people with a measured reason — low energy with the labs otherwise clean, a recovery deficit in older adults, a metabolic marker the precursor trials moved. For those people a precursor or the subcutaneous form is the proportionate first step; the IV adds hours, cost and a reaction without added evidence.

• Infusion reaction. Flushing, chest tightness, nausea, abdominal cramping, a sense of dread — common, rate-dependent, and the reason the drip is slow. Anyone with a cardiac history should treat that as a physician question before the first session.
• Active cancer. NAD+ fuels every rapidly dividing cell; every oncology view urges caution and trial exclusions agree.
• Pregnancy, breastfeeding, under 18 — no data; excluded.
• Kidney disease. High NAD+ turnover loads the kidneys with metabolites; cystatin C before, as with every plan.
• Gout or high uric acid — purine load; worth a baseline check.

Where it fits in a personal protocol

NAD+ sits in the longevity and energy layer of a plan, after sleep, training and the iron, thyroid and vitamin D results have been read — low NAD+ is a far rarer cause of tiredness than low ferritin. When it is included, the protocol usually writes the subcutaneous schedule from the NAD+ research page, because it is cheap, self-administered, avoids the infusion reaction and can be paired cleanly with MOTS-c or epithalon in a longevity block. The longevity goal page shows the whole shape.

A coach can point to a clinic infusion as an option where someone prefers it, cannot self-inject or wants a supervised first exposure. The infusion is performed by a licensed clinic under its own medical oversight; nothing about it is arranged or sold here.

The hype vs the evidence

• "The IV is the only way to get it into cells." The one PK study suggests most of an infusion is broken down before it gets anywhere, and no study has compared routes for tissue levels.
• "You feel it working." The flushing and chest tightness are a vasodilatory reaction to the rate of infusion, not a sign of cellular uptake.
• "Reverses ageing." Mice, and marker changes in small human trials of precursors.
• What is solid: precursors reliably raise blood NAD+ and nudge a few metabolic markers; the biology in animals is compelling; the subcutaneous route avoids the drip's downsides at a fraction of the cost. The outcome data everybody wants does not exist yet, by any route.