Does NAD+ supplementation slow biological ageing?
NAD+ supplements raise your NAD+ levels in the blood, but whether that also means you age biologically more slowly has not been demonstrated in humans at this time. The question is interesting, but firm conclusions cannot yet be drawn; keep an eye on future large-scale research if you are seriously considering this.
NAD+ supplements (such as NMN) reliably and measurably raise NAD+ levels in the blood. A randomised double-blind study involving 80 healthy middle-aged adults achieved this with as little as 300 mg per day, with the strongest effect at 600 to 900 mg per day. So far, the biochemical story is consistent.
But higher blood levels are not the same as slowing biological ageing. Whether NAD+ also rises in muscles, the brain or the liver in humans has barely been studied. Moreover, the available studies do not answer what higher NAD+ levels in the blood actually mean for how the body ages.
As for measuring 'blood biological age': in the same study, this remained stable in the NMN groups while it rose significantly in the placebo group. That sounds encouraging, but the calculation method used for this is contested and has not been confirmed by other researchers. This is therefore one finding from one small study, not established evidence.
In animal research, NAD+ boosters regularly show improvements in metabolism, muscle function and inflammation markers, as well as longer healthy lifespans. But the translation from mice to humans fails for many promising compounds, and there is no reason to expect an exception here until larger human studies confirm it. A large systematic review that assessed 113 studies, of which 33 were in humans, concludes that the clinical efficacy for anti-ageing remains 'inconclusive'.
On the question of safety, the picture is clearer: up to 900 mg per day orally, NMN appears to be well tolerated over periods of weeks to a few months, with no reported side effects. Long-term data in humans are lacking, however. Intravenous NAD+ therapy has no randomised trial behind it whatsoever; claims about intravenous 'anti-ageing' infusions are scientifically unfounded.
Sources: 1 RCT (n=80, PMID 36482258), 1 systematic review (113 studies, PMID 41655607), and 6 reviews (PMID 41083806, 37068054, 37619764, 37848251, 29514064, 35499054). No meta-analysis with pooled clinical outcomes is available.
At what age does taking NAD+ supplements make sense?
There is no established age at which NAD+ supplementation becomes worthwhile; studies focus on middle-aged and older adults, but a measurable functional benefit in humans has not yet been demonstrated. Anyone considering starting does so on the most informed basis after middle age, with realistic expectations.
Does NAD+ cause weight gain?
There is no scientific evidence that NAD+ supplements such as NMN or NR cause weight gain. Animal research even suggests the opposite, but this has not yet been confirmed in humans.
Are NAD+ supplements (NMN/NR) worth it?
NMN and NR demonstrably raise NAD+ in your blood and appear to be safe, but whether you will actually notice any difference in muscle strength, heart function or memory? That is far from proven in humans. Note too: NR is authorised as a supplement in the EU, NMN is not (yet).
Which supplements or medications are best not combined with NAD+?
The combination of NAD+ supplements (particularly nicotinamide) with platinum-based chemotherapy is the most concrete reason for caution; for other interactions the indications are preliminary but worth discussing with your doctor if you are using multiple substances.
What is NAD+ and why does it decline as you age?
NAD+ is an indispensable energy carrier and guardian of your DNA, and your body produces less of it as you age. The mechanisms behind that decline are reasonably well understood, but what you can practically do about it is still very much under investigation.
What is NAD+ and what does it do in your body?
NAD+ is an indispensable molecule for energy, DNA repair and cell health, but the question of whether you should actively raise those levels for better health has not yet been answered for humans.