If you have read anything about NAD+ in the last two years, you have probably absorbed a simple story: NAD+ falls with age, precursors like NMN and NR put it back, and the rest follows. The first half of that story is now well supported. The second half is where the 2026 evidence gets uncomfortable.

A large systematic review published this year pulled together 113 studies — 33 human intervention trials and 80 rodent studies — and landed on a conclusion that is easy to state and hard to sell: oral NR and NMN reliably raise NAD-related metabolites in the blood, are generally well tolerated over weeks to months, and yet their effects on functional, metabolic and vascular outcomes are "heterogeneous and often null or endpoint-specific." In plain terms, the drug hits its target. Whether the target matters is still an open question. That gap — between target engagement and clinical benefit — is the most useful lens for anyone reading NAD+ marketing in Australia right now.

One housekeeping point before we go further, because it comes up constantly in searches: NAD+ is a coenzyme, not a peptide. It sits in our peptides section because it travels in the same longevity-clinic circles, not because it shares any chemistry with BPC-157 or tesamorelin. You can read the background on our NAD+ profile page.

What is NAD+, and why does "raising it" not automatically mean anything?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme every cell uses for energy metabolism and for a family of repair and signalling enzymes. NMN and NR are precursors — building blocks the body converts into NAD+.

The pharmacological logic is clean. Give the precursor, measure blood or cell NAD+, watch it rise. Trial after trial shows exactly that. The 2026 review describes this as "robust pharmacodynamic activity."

But a biomarker moving is not the same as a person improving. Blood NAD+ is easy to measure and easy to move; it may not reflect NAD+ inside the specific tissues where ageing biology is actually going wrong. This is a familiar pattern in clinical research — the surrogate marker responds beautifully, the outcome does not follow — and NAD+ is currently sitting squarely in it.

NAD+ research: three recent trials that show the split

Peripheral artery disease — a genuine positive, but small

The NICE randomised trial gave 90 people with peripheral artery disease six months of NR, NR plus resveratrol, or placebo. Against placebo, NR improved six-minute walk distance by 17.6 metres (+7.0 m for NR vs −10.6 m for placebo) and improved peak treadmill walking time by about 2.1 minutes. Adding resveratrol did not help. Among participants who took at least 75% of their pills, the NR difference was larger at about 31 metres.

That is a real, placebo-controlled positive result in a population with a measurable disability. It is also a modest effect from a single trial of 90 people, and the adherence-based figure is a subgroup analysis rather than the headline finding. A follow-up trial (NICE-PAD II) is registered; until it reports, treat this as promising and unreplicated.

Long COVID — NAD+ up, symptoms unchanged

A randomised, placebo-controlled trial run through Mass General Brigham gave 58 people with long COVID up to 2,000 mg/day of NR. NAD+ levels rose within about five weeks. Between-group differences in cognition, fatigue, sleep and mood were not statistically significant.

This trial is the whole argument in miniature. The intervention did the biochemical thing it was supposed to do, in the right direction, at a high dose — and the people did not measurably feel or perform better than placebo. It is a small study, so it cannot rule out a modest effect, but it is exactly the kind of result that rarely makes it into a supplement landing page.

Blood pressure — pilot-stage, signals in the secondary outcomes

A pilot randomised trial in 54 sedentary adults aged 55+ with elevated daytime systolic blood pressure tested 1,000 mg/day NR with supervised walking, placebo with walking, or NR alone over six weeks. Adherence was high. The reported signals sat in measures like nighttime blood pressure and arterial stiffness rather than delivering a clean win on the primary daytime systolic endpoint. As a pilot, it was designed to inform a larger trial — not to settle anything.

And the intravenous version?

Worth stating flatly: the 2026 review found no eligible outcome trials of intravenous or intramuscular NAD+ for anti-ageing or wellness indications. IV NAD+ drips are among the most heavily promoted and least studied products in this space. That is not a claim that they do nothing; it is a claim that nobody has published the trial.

Is NAD+ legal in Australia? The rules split the family in three

This is where Australian readers need a different mental model to overseas content, because the TGA does not treat NAD+ and its precursors as one category.

  • NMN (oral): permitted. On 10 December 2025 NMN was added to the Permissible Ingredients Determination as an active ingredient for oral listed medicines, with a maximum recommended daily dose of 500 mg. Until 10 December 2027 it can only be used where SyncoZymes (Shanghai) Co Ltd is the sponsor, or where another sponsor has been authorised by them and the TGA notified — a sponsor-exclusivity window, not a general free-for-all. The TGA has also published a compositional guideline covering identity, assay range and impurity limits for the beta-anomer form.
  • NR: permitted as a listed medicine ingredient.
  • NAD+ and NADH: not permitted ingredients in Australian listed medicines.

Two practical consequences follow. First, an Australian product legally containing 500 mg/day of NMN is dosed below several of the trials discussed above (the long COVID study used 2,000 mg/day of NR). Second, "listed medicine" status is a quality-and-safety pathway, not an efficacy verdict — the TGA has not assessed these products for whether they work, and its guidance restricts what sponsors may claim about NAD, NAD+, NADH or NMN.

Internationally, the picture also shifted: the US FDA reversed its earlier position excluding NMN from the dietary supplement definition in September 2025. That is a regulatory reclassification, not new clinical evidence — the trials did not change because the paperwork did.

What a fair reading looks like

  • NMN and NR do raise NAD+ biomarkers. That is settled.
  • Safety over weeks to months looks acceptable in the trials run so far, at the doses tested.
  • Functional benefit is inconsistent — one credible positive in PAD, nulls elsewhere, and a lot of small, short, single-site studies.
  • IV NAD+ has essentially no published outcome evidence.
  • Australian legal dosing for NMN is capped at 500 mg/day and sits under a sponsor-exclusivity arrangement until December 2027.

If you want the plain-English version: the science has proven it can move the dial on the gauge. It has not yet proven the gauge is connected to the engine.

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FAQ

What is NAD+ and is it a peptide?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme involved in cellular energy metabolism and repair signalling — it is not a peptide. NMN and NR are precursors the body converts into NAD+.

Is NMN legal in Australia?

Yes, in a limited form. The TGA added oral NMN as a permitted active ingredient in listed medicines on 10 December 2025, capped at 500 mg per day, with sponsor-exclusivity arrangements running until 10 December 2027. NR is also permitted, while NAD+ and NADH are not permitted ingredients.

Does NMN or NR actually work for anti-ageing?

A 2026 systematic review of 113 studies concluded that oral NR and NMN reliably increase NAD-related biomarkers but that effects on functional, metabolic and vascular outcomes are heterogeneous and often null. Clinical effectiveness for anti-ageing outcomes remains inconclusive.

Is IV NAD+ backed by evidence?

Not meaningfully. The 2026 review identified no eligible outcome trials of intravenous or intramuscular NAD+ for anti-ageing or wellness indications, despite the popularity of IV drips.

Sources

This article is information, not medical advice. retatrutide.net.au is independent, sells nothing and has no commercial ties to any sponsor or supplier. Oral NMN and NR are permitted ingredients in Australian listed medicines under TGA conditions; NAD+ and NADH are not permitted ingredients, and no NAD+ product is TGA-approved as a treatment for ageing or any related condition. Speak to a qualified health professional before starting anything.