NAD+ and Longevity

What is NAD+?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every cell, where it carries electrons through the reactions that produce usable energy and acts as a substrate for enzymes involved in DNA repair and gene expression. That much is textbook biochemistry rather than a wellness claim, and it is the entire basis for the interest in it. What NAD+ is not is a youth molecule — the distance between a real mechanism and a measurable benefit in people is where almost all of the marketing lives.

NAD+ explained

Does NAD+ decline with age?

Several human studies do find lower NAD+ in older tissue, particularly skin and muscle, and the direction is consistent enough to take seriously. The claim is repeated with far more confidence than the data supports, though: NAD+ is unstable and genuinely hard to measure, levels differ between blood, muscle, skin and liver, and most human studies are small and compare younger people with older people at a single moment rather than following the same people as they age. There is no established normal range for NAD+, and your own tissue level cannot be inferred from your age.

NAD+ and longevity guide

Can I get my NAD+ level tested?

No NAD+ test is in routine clinical use, and no commercially available NAD+ test should be used to drive a treatment decision. The molecule starts degrading as soon as a sample is taken, different laboratory methods produce different answers, and there is no reference range to compare a result against. If the real question is why you feel flat, a baseline panel covering thyroid, iron, B12, glucose and hormones answers far more than any NAD+ measurement on the market.

Lab testing

What is the difference between niacin, NR and NMN?

Niacin (vitamin B3), nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are all NAD+ precursors — molecules the body converts into NAD+ — differing mainly in how many steps from NAD+ they sit and in how they are regulated and priced. Precursors exist because cells do not readily take up whole NAD+ from the bloodstream; extracellular NAD+ is largely taken apart at the cell surface and rebuilt inside. Niacin is old, cheap and unpatentable; NR and NMN are newer, proprietary and expensive, which is a large part of why you have heard of them and not of niacin.

Niacin, NR, NMN and NAD+

Do NAD+ precursors actually raise NAD+?

Yes — randomized, placebo-controlled human trials show that oral NR and NMN reliably raise measured NAD+ in blood, and the rise tracks with how much is taken. That finding is solid and reproducible. What has not reliably followed is a clinical benefit: trials looking at insulin sensitivity, muscle strength and function, walking distance, fatigue, blood pressure and cognition have produced mixed results, usually small, in short studies with few participants, and a signal found in one trial often fails to reappear in the next. Raising the number is established; turning that into something you can feel, or a clinician can measure on you, is the step that has not been made.

NAD+ and longevity guide

Does NAD+ slow aging?

No human trial shows that NAD+ therapy slows aging, and anyone telling you otherwise is ahead of the evidence. The mechanism is well described and the research interest is genuine, but what the trials demonstrate is that precursors raise measured NAD+ in blood — not that doing so changes how a person ages. ACT 2 Health does not describe NAD+, or anything else it offers, as anti-aging, because that claim has not been earned.

NAD+ and longevity guide

Is a NAD+ injection better than an oral NAD+ supplement?

Whether a NAD+ injection is better than an oral NAD+ supplement is genuinely unsettled, and nobody can honestly tell you otherwise. Injecting bypasses digestion and briefly produces a far higher blood level than any oral route, which is a real pharmacokinetic difference rather than a marketing one. But circulating NAD+ is broken down quickly and enters cells largely as smaller pieces — roughly what an oral precursor supplies more slowly and more cheaply. Almost all of the human trial evidence was generated with oral precursors, and no good study has compared injected NAD+ with an oral precursor head-to-head on any outcome a patient would care about.

Injection or supplement

Is NAD+ FDA-approved?

No, NAD+ is not FDA-approved. NAD+ injections are compounded preparations and are not FDA-approved for any use — they are not reviewed by the FDA for safety or effectiveness, and they are not equivalent to or interchangeable with any branded product. A licensed clinician may still judge one appropriate for an individual patient, but that is a clinical decision, not a regulatory finding of effectiveness. Any marketing that calls NAD+ therapy FDA-approved is simply wrong.

Is NAD+ FDA-approved?

Is NMN legal to buy in the United States?

NMN's legal status in the United States is contested rather than settled. In 2022 the FDA took the view that NMN is excluded from the statutory definition of a dietary supplement, on the basis that it had already been authorized for investigation as a new drug. The practical result is a compound you can still buy widely online but whose standing as a supplement is disputed. NR is not in that position, and niacin is a recognized vitamin that has never been in question. None of this says anything about whether NMN works — regulatory status and efficacy are different questions.

Is NAD+ FDA-approved?

How long before I would notice anything from NAD+ therapy?

There is no reliable timeline for NAD+ therapy, because there is no established effect to put a timeline on. People who report a change usually describe it within days to a few weeks, and those reports are not the same thing as evidence. The defensible way to approach it is a trial with a defined endpoint and a date to review it — including the honest conclusion that nothing changed — rather than a subscription that renews while nobody is looking.

How quickly NAD+ works

Why do people say they feel great after a NAD+ infusion?

Because they usually do feel better, and because the setting is close to a perfect placebo environment: real expense, a trip, an hour of clinical attention, and a decision made in advance that this would help. Placebo responses are largest for exactly the outcomes this category sells — energy, mood, focus, general well-being — and they scale with price and ritual. People also tend to start at a low point, and low points drift back toward a person's own average without any help, and few people start an infusion in isolation rather than alongside better sleep or new training. Personal testimony cannot separate the compound from the circumstances; only a controlled trial can, and for injected NAD+ that trial has not been done.

NAD+ and longevity guide

Are there side effects from NAD+ injections?

The commonly reported effects of NAD+ are flushing, nausea, cramping, chest tightness and a sensation of pressure during or shortly after administration, and they are closely tied to how fast it is given — slower administration generally means less of it. Injection-site soreness, redness and bruising also occur. The long-term safety of injected NAD+ has not been established in controlled human studies, which is a different and more honest statement than saying it is safe.

NAD+ side effects

Does NAD+ interact with medications?

NAD+ has no well-characterized interaction profile, which is itself the reason to disclose everything you take before starting it. Tell your clinician about all prescription medications, over-the-counter drugs and supplements — niacin taken alongside a statin, anything affecting the liver, and blood thinners all matter. Anyone in active cancer treatment should raise NAD+ with their oncologist before starting, because the enzymes that consume NAD+ are involved in DNA repair and that question belongs to the team managing the cancer.

NAD+ and other medications

Who is a good candidate for NAD+ therapy?

A good NAD+ therapy candidate is an adult whose fundamentals are already in place and who has had the common causes of fatigue ruled out on a blood panel. Those fundamentals are sleep, resistance training, protein and cardiovascular risk addressed — and the person wants to try the category understanding that the case for it is mechanistic rather than clinical. Anyone whose thyroid, iron, B12, glucose, hormones or sleep apnea has not yet been checked is not a candidate, because several of those have far better answers than an infusion. Curiosity is a legitimate reason to try it; the expectation of a specific result is not.

Who NAD+ suits

Who should avoid NAD+ therapy?

NAD+ therapy is not appropriate during pregnancy or breastfeeding, or for anyone with a known sensitivity to the preparation. Anyone with active cancer, significant liver or kidney disease, or an unstable medical condition should not start it without the clinician managing that condition involved in the decision. It is also the wrong move for anyone whose fatigue has not been investigated yet. A licensed clinician makes this judgment individually, and completing an assessment does not mean a prescription follows.

NAD+ therapy

Does NAD+ help with brain fog?

No human trial shows that NAD+ improves brain fog, memory or concentration. Small studies have measured NAD+ in the brain and in cerebrospinal fluid after precursors are taken, which tells you something crossed — not that thinking improved. Brain fog after 45 has a long list of testable causes, including poor sleep and undiagnosed sleep apnea, thyroid disease, anemia, B12 deficiency, perimenopause, depression, alcohol and medication effects, and working through those is a better first move than an infusion.

NAD+ and cognition

Can I raise NAD+ without an injection?

Yes — the oral precursors niacin, NR and NMN reliably raise measured NAD+, and that is the route most of the human research actually used. Exercise, adequate sleep and limiting alcohol act on the same system and cost nothing. The catch is identical in every case: raising the level is well demonstrated, and what raising it does for you is not.

Raising NAD+ naturally

Do B12 injections give you energy?

B12 injections correct a B12 deficiency, and where a deficiency was genuinely causing the fatigue, treating it can make a real difference. Giving B12 to someone whose level is comfortably normal does nothing — there is no energy benefit in topping up a replete person, whatever a drip-bar menu implies. Which is why the answer to whether you should be getting B12 shots starts with a blood test rather than with a booking.

B12 injection

Who is at risk of B12 deficiency after 45?

B12 deficiency becomes more common with age and clusters in identifiable groups: people taking metformin or long-term acid-suppressing medication, people with reduced stomach acid, and vegetarians and vegans. The risk also covers anyone who has had surgery affecting the stomach or ileum, people with pernicious anemia, celiac disease or Crohn's disease, and anyone with repeated nitrous oxide exposure. Left untreated it produces anemia and a neurological picture — numbness, tingling, unsteadiness, memory change — that is not always fully reversible once established. It is measurable on a straightforward blood test, which is what makes it worth checking rather than guessing at.

B12 absorption groups

Do I need B12 injections, or will tablets work?

Whether you need B12 injections or B12 tablets depends on why you are low. Where the problem is intake — a diet with little or no animal protein — oral B12 generally works well. Where the problem is absorption, as in pernicious anemia or after surgery affecting the stomach or ileum, injections bypass the step that is broken, although oral treatment also works for some people through a second, passive absorption route that does not depend on intrinsic factor. Neurological symptoms are usually treated by injection to begin with, and that decision belongs with a clinician who has seen your results.

Tablets or injections

Does injected glutathione do anything?

Glutathione is the body's principal intracellular antioxidant, and whether giving it from outside changes anything in a healthy adult is a far weaker case than the marketing suggests. Injected glutathione does reach the bloodstream, unlike the swallowed form, which is largely dismantled in digestion into its component amino acids — but the human outcome evidence is sparse, and much of what exists concerns skin pigmentation rather than energy, recovery or detoxification. Glutathione injections are compounded and are not FDA-approved, and there is no good human trial evidence that an injection delivers an antioxidant or detoxification benefit for an adult in midlife.

Glutathione injection

Is rapamycin approved for longevity?

No — rapamycin (sirolimus) is FDA-approved to prevent organ transplant rejection and to treat lymphangioleiomyomatosis, not for aging, longevity or healthspan. Prescribing it for longevity is off-label use, which is legal and common in medicine but means the approval behind the drug says nothing whatever about that use. Rapamycin is a genuine immunosuppressant with real risks, and it belongs only under close clinical supervision with monitoring and lab follow-up.

Rapamycin

Does rapamycin extend lifespan in humans?

No completed human trial shows that rapamycin extends lifespan or healthspan in people. The interest comes from animal work, where rapamycin lengthens life in laboratory mice more consistently than any other compound tested, and from the fact that it acts on mTOR, a pathway central to aging biology. Whether any of that transfers to humans is unknown: the human studies so far have been small and short and have measured markers rather than outcomes, and the intermittent schedules used in longevity practice are not the ones transplant medicine uses.

Sirolimus and rapamycin

What does DHEA do, and is pregnenolone worth taking?

DHEA is an adrenal hormone the body converts into testosterone and estrogen, it declines with age, and it is measurable on a blood test. The human trial evidence for supplementing it is narrow, though, with the clearest signals in specific clinical situations rather than in generally healthy adults. Pregnenolone sits a step further back in the same pathway and has substantially less human evidence behind it; most of what is claimed for pregnenolone is claim rather than trial result. Both are hormones rather than vitamins, and both are worth measuring and discussing with a clinician before being taken, rather than bought because they appear on a longevity menu.

What DHEA does

What actually has the strongest evidence for healthspan?

The strongest evidence for healthspan is behind sleep, resistance training, enough protein to support that training, managing cardiovascular risk, and not smoking. Sleep includes finding out whether you have undiagnosed sleep apnea, and cardiovascular risk means blood pressure, ApoB, Lp(a), glucose and insulin. Every one of those is supported by human evidence of a quality nothing injectable in the longevity category comes close to matching, and several of them are free. If those fundamentals are not in place, no infusion makes up the difference and the money is better spent almost anywhere else. If they are in place and NAD+ still interests you, that is a perfectly reasonable position to hold — it is simply a different one from where most people start.

NAD+ and longevity guide

Is methylene blue FDA-approved for energy or cognition?

No — methylene blue is not FDA-approved for energy or cognition. It holds an FDA approval for one specific blood disorder, methemoglobinemia, and every other use — energy, focus, cognition, longevity — is off-label. Off-label prescribing is legal and ordinary in medicine, but it means the approval behind the drug says nothing about the use being discussed. ACT 2 Health considers methylene blue only for eligible patients under clinical oversight, after the screening its interactions require.

Methylene blue

Can I take methylene blue with an antidepressant?

For most people, no: methylene blue taken with an antidepressant can cause serotonin syndrome, which can be fatal. Methylene blue inhibits monoamine oxidase A and raises serotonin, and combined with an SSRI, SNRI, MAOI or most other antidepressants it can cause serotonin syndrome — the FDA issued a formal warning on this interaction in 2011. The same caution covers tramadol and some other opioids, triptans, dextromethorphan, lithium, buspirone, St John's wort and linezolid, and occasional use still counts. Stopping an antidepressant in order to take methylene blue is not a trade ACT 2 Health will suggest or support; that decision belongs to your prescriber.

Methylene blue and antidepressants

Do I need a G6PD test before taking methylene blue?

Yes, you need a G6PD test before taking methylene blue. Methylene blue is an oxidizing agent, and in someone with G6PD deficiency it can rupture red blood cells, causing severe anemia and kidney injury — it is a labeled contraindication rather than a precaution. G6PD deficiency is the most common human enzyme deficiency and most carriers have no idea they have it, because they have never met a strong enough oxidative stress to find out. ACT 2 Health draws G6PD with the baseline panel and does not prescribe methylene blue without a result, regardless of how well you have tolerated other medications.

Methylene blue and G6PD

Why does methylene blue turn urine blue-green?

Methylene blue is a dye and is cleared by the kidneys, so a blue or green tint to urine is the expected consequence of taking it rather than a sign of a problem. The color appears within hours and fades as the compound clears. It is worth knowing in advance, and worth mentioning to anyone running a urine test on you, since the color can interfere with how some results are read.

Methylene blue

Is aquarium-grade methylene blue the same as pharmaceutical-grade?

No — aquarium-grade methylene blue is not the same as pharmaceutical-grade, and the difference is purity and contaminant profile rather than branding. Methylene blue sold for aquarium or laboratory use is not manufactured to standards for human consumption and can carry heavy metal contamination. The only appropriate material for the uses discussed here is pharmaceutical-grade, prepared by a licensed compounding pharmacy against a prescription written for you — which is a statement about quality of the ingredient, not a claim that a compounded preparation is FDA-approved or equivalent to an approved product.

Methylene blue

Does methylene blue improve memory?

The human evidence that methylene blue improves memory is one small placebo-controlled fMRI study in healthy adults, which found increased activity in attention and short-term-memory regions and a modest improvement on a retrieval task about an hour after a single administration. That demonstrates a mechanism rather than a treatment, and no trial has tested methylene blue for cognition in healthy people over weeks or months. A modified version of the molecule was tested for Alzheimer's disease and failed its two large phase 3 trials in 2016, which is a different molecule and a different question but not an encouraging one.

Methylene blue and cognition

Should I take methylene blue for brain fog?

Get the brain fog worked up before considering methylene blue, because the common causes — poor sleep and undiagnosed sleep apnea, thyroid disease, anemia, low B12, perimenopause, depression, alcohol and medication effects — are testable and several of them are treatable. If those have been addressed and you still want to try methylene blue, it has to be done with the interaction screening that its serotonin syndrome and G6PD risks require, and with realistic expectations: the evidence for a noticeable subjective effect is early and response varies a lot. A trial with a defined checkpoint, and a genuine willingness to stop, is the defensible way to approach it.

Methylene blue and cognition

What are the risks of taking rapamycin?

The principal risk of rapamycin is immunosuppression, which raises infection risk and impairs wound healing. Rapamycin can also raise cholesterol and triglycerides, affect blood sugar handling, and cause mouth ulcers, and it interacts with a long list of common medications. It is not a supplement with a safety margin to spare — it is a genuine immunosuppressant, the eligibility screening is a real screen, and it belongs under close clinical supervision with scheduled laboratory follow-up.

Rapamycin

Does rapamycin weaken your immune system?

Rapamycin does weaken the immune system at the continuous exposure used in transplant medicine — that is the point of the drug there. In the intermittent schedules used in longevity practice the picture looks different: a year-long randomized trial found no excess of infections or serious adverse events compared with placebo. That is reassuring rather than settled, because longer and larger safety data do not exist, and immunosuppression remains the risk that drives the monitoring and the eligibility criteria.

Rapamycin, infections and vaccines

Can I get vaccines while taking rapamycin?

Inactivated vaccines — the flu shot, COVID vaccines, pneumococcal vaccine and the modern shingles vaccine — are given as normal while taking rapamycin. Live vaccines are avoided, which covers MMR, yellow fever, the nasal flu spray and oral typhoid, so travel vaccination plans need to be raised in advance. Tell whoever is vaccinating you that you take rapamycin, and tell your prescriber before booking travel immunizations.

Rapamycin, infections and vaccines

Do I need to stop rapamycin before surgery?

Rapamycin impairs wound healing, so it is paused before surgery and restarted once healing is underway — and that includes significant dental procedures, which people routinely forget to mention. This needs to be planned rather than improvised, so tell your prescribing clinician about any procedure well in advance and tell your surgeon or dentist that you take it. If you become unwell on rapamycin — a fever, anything needing antibiotics, anything not resolving normally — pause and contact your clinician rather than deciding alone.

Rapamycin, infections and vaccines

Does rapamycin interact with other medications?

Yes, extensively, because rapamycin is metabolized through the CYP3A4 pathway that a great many common drugs also use. Several antibiotics and antifungals can raise rapamycin exposure considerably, and statins, some blood pressure medications and grapefruit are all part of the picture. Bring a complete list to your evaluation, including occasional medications and supplements, and make sure any clinician prescribing you something new — particularly for an infection — knows you take rapamycin.

Rapamycin

What lab monitoring does rapamycin require?

Rapamycin requires a baseline panel and then scheduled follow-up covering lipids, glucose and HbA1c, blood counts, and kidney and liver function. The monitoring is not a formality: most of what rapamycin changes produces no symptoms at all until it is well advanced, so the laboratory work is how a problem is found. Anyone offering rapamycin without a monitoring schedule attached to it is not offering it safely.

Rapamycin

Does rapamycin cause mouth ulcers?

Yes — canker-sore-like ulcers are the most commonly reported side effect among people taking rapamycin for longevity, and they arise because the drug slows cell turnover in the fast-renewing lining of the mouth. They are a local effect rather than a sign of infection or immune failure, and most people who get them find they appear in the first weeks and become fewer and milder after that. Severe or persistent ulcers can indicate that exposure is higher than intended, sometimes through a drug interaction, so report them rather than stopping on your own.

Rapamycin mouth ulcers

Is sirolimus the same as rapamycin?

Yes — sirolimus and rapamycin are the same molecule, one with three names. Rapamycin is the name it was given at discovery, sirolimus is its official generic name, and Rapamune is the brand it was approved under. Generic sirolimus is approved on bioequivalence to the branded product and is what most patients take; ACT 2 Health dispenses the FDA-approved manufactured tablet rather than a compounded version, since a comparison study found compounded rapamycin delivered substantially less drug into the blood than the approved product.

Sirolimus and Rapamune

Does taking DHEA actually work?

DHEA has support in narrow, specific situations — adrenal insufficiency, and an approved intravaginal product for painful intercourse after menopause — and trials of DHEA for energy, muscle, cognition or general vitality in otherwise healthy adults have largely been negative. It raises testosterone somewhat and unpredictably, which makes it neither a substitute for testosterone therapy where that is indicated nor a reliable way to raise testosterone. Measuring DHEA-S is worth doing where an adrenal problem or androgen excess is suspected, but the result is not a useful guide to whether supplementing would help you.

What DHEA does

Is DHEA safe to take?

DHEA is a hormone precursor rather than a vitamin, and it converts into testosterone and estrogen with the effects that follow from that, so whether it is safe depends on the individual. Anyone with a history of hormone-sensitive cancer should not take DHEA without specialist advice, and anyone already on hormone therapy should tell their prescriber first — DHEA adds an unmeasured androgen and estrogen precursor to a regimen being adjusted toward a target, which makes both harder to interpret. Over-the-counter DHEA carries a further problem: supplements are not evaluated by the FDA for content accuracy, and independent testing has repeatedly found products that do not match their labels.

Is DHEA safe?

Does pregnenolone help memory or adrenal fatigue?

Pregnenolone is a genuine neurosteroid and there is real research interest in it, mostly in specific clinical populations — but a cognitive benefit in healthy adults is not established, and most of what is claimed for pregnenolone is claim rather than trial result. It does not reliably raise testosterone or DHEA either, because the conversions downstream of it are enzyme-regulated and tissue-specific, so adding substrate does not predictably increase any particular hormone. Adrenal fatigue is not a recognized medical diagnosis; adrenal insufficiency is a real and different condition that needs proper diagnosis and medical management rather than a supplement.

What pregnenolone is

Is any drug proven to slow aging in humans?

No — no drug, supplement or injectable has been shown in humans to slow aging, reverse it or extend life. That includes every compound in the longevity category — NAD+ and its precursors, rapamycin, metformin, methylene blue and the peptides marketed alongside them. Several have real mechanisms and interesting animal data, and a few are being studied seriously, but animal lifespan data and human marker studies are not the same as a demonstrated human outcome. Anyone selling certainty here is selling marketing.

NAD+ and longevity guide

Why does ACT 2 Health avoid the term anti-aging?

Because anti-aging sets an expectation nothing on the market can meet, and a clinic that uses the term has already agreed to overstate. The goal ACT 2 Health works toward instead is healthspan — more years spent strong, sharp and independent — which is built mostly out of sleep, resistance training, protein, cardiovascular risk management and not smoking. Anything from the longevity menu sits on top of that as a possible complement with honest uncertainty attached, never as a substitute for it.

NAD+ and longevity guide

Results vary. Clinical trial results apply only to the FDA-approved branded medication specifically identified and do not apply to compounded medications. All medications must be prescribed by a licensed provider based on medical necessity.