IV Therapy and NAD+: The Science Behind Cellular Energy

NAD+ is one of the most popular molecules in longevity right now, and one of the most over-marketed. It's also genuinely important. Both can be true. The job of a clinician is to keep the signal and skip the noise.

What NAD+ does

Nicotinamide adenine dinucleotide — NAD+ — is a coenzyme present in every living cell. It's involved in three big jobs:

• Energy production. NAD+ is essential for converting food into ATP via the electron transport chain. Less NAD+, less efficient energy production.
• DNA repair. The PARP enzymes that repair DNA damage consume NAD+ to do their work. Chronic damage drains the pool.
• Sirtuin activity. The sirtuin proteins, central to several longevity pathways studied by David Sinclair and others, require NAD+ as a substrate. No NAD+, no sirtuin activity.

NAD+ levels decline with age — the data on that is consistent. By age 50, tissue NAD+ levels are roughly half what they were at 20. The hypothesis driving NAD+ supplementation is that restoring those levels restores some of the function that depends on them.

What the evidence supports

Animal models — including rodents and primates — show clear benefits of NAD+ precursor supplementation: improved mitochondrial function, better metabolic health, improved insulin sensitivity, and in some studies, extended healthspan. The molecular biology is robust.

Human data is more mixed. The cleanest finding is that NAD+ precursor supplementation reliably raises blood NAD+ levels. Whether that translates into clinically meaningful endpoints — energy, cognitive function, mortality — is where the evidence becomes thinner and more population-dependent. Studies in older or metabolically compromised adults are more positive than studies in healthy young adults, which is roughly what you'd expect.

The delivery question

Three main ways to deliver NAD+ or its precursors:

1. Oral precursors (NMN, NR). Convenient, well-tolerated, less expensive. Reliably raises NAD+ levels in blood. Good for steady-state, multi-year protocols.
2. Subcutaneous injection of NAD+ itself. Higher bioavailability than oral; less expensive than IV. We use this for patients who want intermittent boosts without the time commitment of an infusion.
3. IV NAD+ infusion. The most direct delivery, the most dramatic increase in plasma levels, and historically the favorite of biohacker influencers. Also the most expensive, the most time-consuming, and the most likely to produce the side effect everyone underestimates: discomfort during the infusion (chest pressure, anxiety, GI upset). It's not dangerous when done correctly, but it's not pleasant either.

What we actually do with it

NAD+ is a tool, not a strategy. Our typical approach:

• Start with the upstream interventions. Sleep, resistance training, protein intake, body composition. NAD+ levels respond to all of these. Supplementing on top of a broken foundation is a poor use of money.
• Use oral precursors as the daily baseline when supplementation is indicated.
• Reserve injection or IV for specific cases: recovery from illness, jet lag protocols, post-surgical recovery, or specific aging biomarkers that warrant a more aggressive approach.
• Measure where it's reasonable. NAD+ blood testing exists but is imperfect; we more often track downstream markers — biological age, energy, recovery, inflammation — that reflect whether the protocol is doing what we want.

The honest summary

NAD+ supplementation is real medicine with real upside, especially for adults over 40 with declining mitochondrial function or recovery capacity. It is not a fountain of youth, and IV NAD+ at $500+ a session is rarely the highest-leverage use of a longevity budget for a healthy 35-year-old who isn't sleeping enough. Used in the right context, with the right delivery, alongside the upstream work — it earns its place in the toolkit.