NMN and NAD+: what they are, what the studies show and why the route of administration matters

If you have landed here searching for “NMN”, you are probably looking for an answer to a simpler question: can anything concrete be done for cellular energy and for the processes involved in ageing? It deserves an honest answer, which in Romanian is almost entirely missing — most content on the subject is written to sell capsules.

We do not sell capsules. We explain the real biochemical chain, what the human data show and where their limits are.

NAD+, in brief

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every cell, with a central role in producing cellular energy and involved in DNA repair. Its level falls with age — which is why it has become a central subject in longevity research.

We have covered separately what is and is not proven about it, including the commercial exaggeration, in What NAD+ is (without the hype). We will not repeat it here; if you want the groundwork, read that first.

What NMN is and how it relates to NAD+

NMN — nicotinamide mononucleotide — is a precursor of NAD+. In other words, it is not the active molecule but one of the substances the body builds it from.

The logic behind the interest in NMN is simple and, in principle, sound: if NAD+ falls with age and NMN is the last link before NAD+ in one of the synthesis pathways, then supplying NMN might support NAD+ production. It is a rational hypothesis, intensively tested — not a marketing invention.

Its popularity, however, comes from elsewhere: from a series of results obtained in animal models, where NMN supplementation produced notable effects on some markers linked to ageing. These results were taken up enthusiastically, and the distance between a laboratory mouse and a 55-year-old human was overlooked almost everywhere.

NMN's status in the European Union

This is the part almost nobody mentions, even though it changes the discussion completely for a reader in Romania.

In the European Union, NMN is classed as a novel food, which means that placing it on the market as a food supplement requires prior authorisation.

The procedure is under way. The European Food Safety Authority (EFSA) adopted a positive scientific opinion on 4 March 2026, published on 11 May 2026: beta-NMN is considered safe under the proposed conditions of use, for adults, except pregnant and breastfeeding women, as a source of niacin, up to 300 mg a day.

A favourable EFSA opinion is not, however, an authorisation. The final step belongs to the European Commission and the member states, through inclusion in the Union list and publication in the Official Journal. As of the publication of this article — August 2026 — this step had not been completed.

What this means in practice: this article is for information. We do not recommend taking NMN, we do not administer it and we do not point to places to buy it. The status may change, and if it does, this section will be updated.

What the human data show — the honest part

This is the difference between this article and the rest.

Human studies exist, but they need to be read carefully for size and duration:

• A randomised, double-blind trial published in Science in 2021 gave NMN for 10 weeks to 25 women who were postmenopausal, overweight or obese, with prediabetes. The result: increased insulin sensitivity in skeletal muscle. Insulin sensitivity in the liver and in adipose tissue did not change.
• A study published in npj Aging in 2022 showed that chronic NMN supplementation raises blood NAD+ levels and alters some muscle function parameters in healthy older men.
• Safety studies, including in healthy adults, reported good tolerance, with no significant adverse effects at the doses tested.

And now the limits, which matter just as much:

A review of human clinical trials, published in Advances in Nutrition in 2023, shows that most are at phase I level, with between 8 and 66 participants; the largest included 108 people. A 2024 meta-analysis of glucose and lipid metabolism found no significant effects on body weight or body mass index.

How this translates. A rise in blood NAD+ is a biological marker, not a clinical benefit. A 10-week study in 25 women, finding a change in a single tissue, is a research signal — not proof that the molecule “slows ageing”. The direction is promising. “Promising” and “proven”, however, remain two different things, and a serious clinic acknowledges the difference.

Nor do we exaggerate in the other direction: NMN is not a scam. It is a seriously studied molecule, in a real field, with a human evidence base that is still at an early stage.

Why the route of administration matters

For molecules in this family, the route of administration is not a detail — it is often the decisive part.

Any substance taken by mouth passes through the digestive tract and the liver before it reaches the systemic circulation. For many molecules, a significant part is lost along the way. That is why, for some substances, the oral and intravenous forms produce very different blood concentrations for the same amount given.

Here we need to be precise, because this is exactly where figures get invented. We will not give a bioavailability percentage for NMN: the published human data do not support a single value, and a round figure taken from a commercial article does not become true by being repeated. What can be said correctly, qualitatively, is that oral administration involves intermediate metabolism, and the intravenous route bypasses it.

What we know about intravenous NAD+ comes from a human pilot pharmacokinetic study that followed what happens in plasma and urine during a six-hour infusion. The result is instructive in both directions: NAD+ is cleared rapidly and completely from plasma within the first two hours, and the metabolite profile is consistent with enzymatic breakdown; only after this interval do measurable changes in metabolites appear. In other words, the molecule reaches the circulation and is actively metabolised — but the question of whether, and how much, intact NAD+ enters cells as such remains open in the literature.

We say this even though it does not help us commercially. It is the real debate in the field, and we would rather you heard it from us.

What we administer and how

At Synerva we administer intravenous NAD+, not NMN.

The protocols are:

• NAD+ 100 mg — 600 RON, slow administration, around 90 minutes. A suitable starting point for a first session or for maintenance.
• NAD+ 250 mg — 1,250 RON, 120–180 minutes. A more concentrated dose.
• NAD+ Longevity course — 4,290 RON, four sessions of 250 mg, because the effects build up over a series, not from a single administration.

Administration is deliberately slow, and the reason is concrete: at too fast a rate, NAD+ can cause passing discomfort — chest pressure, nausea, flushing. These are not danger signs; they are linked to the rate of administration, and the solution is to slow it down. That is why an NAD+ drip takes hours, not minutes, and why it is done under medical supervision, with the rate adjusted according to how you feel.

Full details on the protocol, doses and what happens during the session are on the NAD+ IV drip in Bucharest page, and the practical side — who it makes sense for and with what expectations — in the benefits of an NAD+ IV drip.

What we do not promise

Short and clear, because honest positioning builds more trust than superlatives:

• NAD+ is not a treatment for any disease and we do not present it as one.
• It does not reverse ageing. No molecule in this category has human evidence for such a claim.
• It does not replace sleep, exercise and diet — the foundations of any serious longevity strategy, with evidence incomparably stronger than any drip.
• The clinical evidence is still being built. We position NAD+ as part of a longevity routine, with realistic expectations.

If, at the assessment, the conclusion is that it does not make sense for you, we will tell you directly. It happens.

---

Sources

Yoshino M. et al. — Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women, Science, 2021: the randomised trial in 25 women, with the result limited to skeletal muscle.

Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men, npj Aging, 2022.

The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update01359-5/fulltext), Advances in Nutrition, 2023: the review of human trials, sample sizes and phase I level.

Efficacy of oral nicotinamide mononucleotide supplementation on glucose and lipid metabolism for adults: a systematic review with meta-analysis on randomized controlled trials, Critical Reviews in Food Science and Nutrition, 2024.

EFSA — Safety of beta-nicotinamide mononucleotide (β-NMN) pursuant to Regulation (EU) 2015/2283, EFSA Journal, 2026: the scientific opinion adopted on 4 March 2026, the proposed conditions of use and novel food status.

Grant R. et al. — A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+, Frontiers in Aging Neuroscience, 2019: the pharmacokinetics of intravenous NAD+ in humans.

This article is for information only and does not replace a medical consultation. It is not a recommendation to take any food supplement.