NAD+ cycle length: is there a right way to handle it

Someone on r/Biohackers asked a version of the same question I get from clients constantly: is it necessary to cycle NAD+ SubQ injections, or can you just run it continuously once you find a dose that works? Short answer: no, you don't strictly have to cycle NAD+, but the three-months-on, one-month-off protocol that practitioners have converged on is worth following, because the reasoning behind it is sound even though it hasn't been directly tested in a controlled human trial yet.

Let's get into why that answer isn't a dodge.

What NAD+ actually is, and why cycling even comes up

NAD+ (nicotinamide adenine dinucleotide) is the coenzyme your mitochondria use to convert food into usable energy, and it's also the fuel that a family of repair enzymes, the sirtuins, runs on. It falls with age, and that decline traces mainly to consumption: an aging-related enzyme called CD38 chews through NAD+ faster as inflammation rises, and knockout mice that lack CD38 maintain youthful NAD+ levels at every age tested, which points to CD38 activity as the main driver of the decline. You can read the mechanism in more depth on the NAD+ page.

The cycling question comes from a specific clinician claim, not from safety data: when you supply NAD+ externally on a steady basis, your body may sense it has plenty and dial back its own synthesis machinery, the same feedback logic that governs a lot of endocrine systems. That's a real biological pattern in other contexts, but for NAD+ specifically, nobody has run the study that confirms it. That gap is real. The cycling advice comes from clinical reasoning about a plausible mechanism, and no randomized trial has tested it directly.

The protocol people are actually running

Here's what shows up across the practitioner training material I've reviewed and what our own SubQ NAD+ clients report using. You start low: 25 mg twice a week for the first two weeks, then step to 50 mg twice weekly, then to 100 mg twice weekly by weeks five through eight. That ramp matters because jumping straight to a high dose tends to produce the same jittery, racing-heart sensation people get from IV NAD+ done too fast. After the loading phase, maintenance drops to around 100 mg weekly, every other week, or monthly, depending on how you're feeling. Then comes the cycle: roughly three months on, one month off, and when you restart, you don't repeat the full ramp, you go back in at 50 mg and step up to 100 mg over a couple weeks.

I use SubQ NAD+ myself on a similar rhythm, and the month off hasn't cost me anything noticeable in energy. If anything it's a useful checkpoint to notice whether the effect was still doing something or whether I'd plateaued without realizing it.

The plateau piece is worth naming directly, because it's the other half of why people ask about cycling. A common pattern with steady NAD+ use is a flattening of benefit around 8 to 12 weeks, driven by your NAD+ metabolism consuming methyl groups faster than you're replacing them. Adding TMG (trimethylglycine) as a cofactor is one practical fix, and it can run alongside cycling or instead of it depending on what you're chasing.

On the oral side, this same underlying biology plays out differently. NR reliably raises blood NAD+ in a dose-dependent way, with a randomized trial showing +22%, +51%, and +142% increases at 100, 300, and 1000 mg respectively, and that data set doesn't report the same feedback-suppression concern that drives SubQ cycling talk, probably because oral precursor conversion runs through your existing enzymatic machinery differently than a direct NAD+ bolus does.

What the evidence actually supports, and where it stops

I want to separate two different claims cleanly, because conflating them is how misinformation happens. Claim one: NAD+ declines with age and restoring it supports mitochondrial function and DNA repair. That's well established, and a couple of solid reviews back the mechanism, one from Imai and Guarente and one from Verdin, both laying out how sirtuins and DNA-repair enzymes depend on the NAD+ pool. Claim two: continuous NAD+ dosing suppresses your endogenous production enough that you need scheduled breaks to reset it. That one is mechanistically plausible, product inhibition of enzymes is a pretty standard biological pattern, but it hasn't been directly measured for NAD+ supplementation in a controlled human trial. The practitioner protocol treats it as defensible caution, and so do I, but don't mistake it for something with the same evidence weight as the CD38 data.

Where the evidence is genuinely strong is on the exercise side of this equation, which nobody thinks to ask about in a cycling thread but probably should. Exercise increases NAMPT, the enzyme that runs the NAD+ recycling pathway, and a human trial found skeletal muscle NAMPT protein rose about 127% after just three weeks of training in previously sedentary people. If you're worried about your body's own NAD+ production stalling out, training consistently does more for that concern than any cycling schedule will, and it costs nothing.

A note on scope: the doses and schedules here are for educational and informational purposes only. These peptides are sold for research use only and are not FDA-approved drugs. This is not medical advice. Consult a qualified physician before beginning any protocol.

Where this fits if you're stacking

If you're running NAD+ alongside anything else, the cycling question gets a little more practical. People running NAD+ with a fat-loss peptide or a mitochondrial compound like MOTS-c often find the three-on, one-off rhythm lines up naturally with how they'd already be reassessing a broader stack. If you're new to the injectable side of peptides generally and wondering how much risk is actually on the table with compounds like this, the piece on whether peptides are dangerous is a good companion read before you commit to a schedule.

One more practical note: the hard contraindications for NAD+ across every route (oral, SubQ, IV) are active cancer and pregnancy or breastfeeding. Those aren't cycling questions, they're stop-and-don't-start rules, and they matter more than any debate about dosing schedule.

If you're deciding between running NAD+ continuously or on a cycle, and you don't have a specific reason to avoid the break (travel, a big event, whatever), I'd default to the three-on, one-off pattern simply because it costs you almost nothing and it matches what the people training this protocol in clinics are actually doing day to day. It's a reasonable default until someone runs the study that settles the endogenous-suppression question either way.