What is the relation between NAD+ and vitamin B3?
Vitamin B3 is the only dietary building block for NAD+ in your body; that relationship is causal and well supported. Whether NAD+ supplements such as NMN or NR genuinely deliver health benefits has yet to be proven.
Your body does not simply produce NAD+ on its own. It needs vitamin B3 as a building block. Vitamin B3 is not a single substance but a family: niacin, nicotinamide, and more modern variants such as NMN and NR. All of these forms are raw materials that cells use to produce NAD+. An intake that is too low through diet leads directly to an NAD+ deficiency.
NAD+ is indispensable in hundreds of energy-generating reactions in your cells, including the functioning of the mitochondria, the power plants of your cell. In addition, proteins that repair DNA damage and switch genes on and off consume NAD+ as a raw material. It is therefore both an energy molecule and a regulator of your cellular health.
NAD+ levels decline measurably with age. Whether that decline can be countered with vitamin B3 supplements, and whether doing so also reverses symptoms, has not yet been proven in humans. There is a great deal of positive research in mice, but the step toward solid evidence in humans is still small.
The more modern and more expensive variants NMN and NR are largely converted to nicotinamide in the liver before they reach other tissues. The route through your body therefore strongly determines what such a supplement actually does. Ordinary niacin showed promising results in mouse studies on muscle breakdown in cancer: it restored NAD+ in tissues and improved mitochondrial function in muscles.
In humans, the data are scarce. A small study involving 30 Parkinson's patients (1000 mg NMN-related supplement per day, 30 days) showed a variable increase in NAD+ in the brain, along with less inflammation and a mild improvement in participants who produced more NAD+1,2,3,4,5,6,7,8. In mouse studies on Alzheimer's disease, five months of supplementation reduced inflammation in the brain and improved memory. These are preliminary results, not proof of efficacy. Too little is still known about long-term safety, and experts advise waiting for larger studies.
Based on multiple review articles and studies in humans (PMID 34041853, 29249689, 39026037, 33930322, 29685734, 37012289, 35235774, 34497121). The studies in humans are small and limited in number. Most of the functional evidence on disease treatment comes from mouse studies.
What is NAD+ and why does it decline as you age?
NAD+ measurably declines with ageing, and supplements raise levels demonstrably in people. Whether that also makes you healthier has not yet been proven, and the safety of taking them for many years deserves attention.
Does NAD+ cause weight gain?
Research into NAD+ supplements such as NMN and NR shows that they do not cause weight gain. In people with overweight or obesity, there are early indications of a small weight loss.
What is the link between fatty liver and type 2 diabetes?
Fatty liver and type 2 diabetes reinforce each other: they share the same underlying mechanism and roughly double each other's risk. If you have a fatty liver, addressing it is also a way to reduce your risk of diabetes.
Does magnesium help with insulin resistance?
There is reasonable evidence that magnesium has a beneficial effect on insulin resistance, particularly if your magnesium levels are too low. If you have a condition like insulin resistance, always discuss supplementation with your doctor before starting.
What is NAD+ and what does it do in your body?
NAD+ is an indispensable molecule for energy, DNA repair and cell maintenance, and its levels measurably decline with age. Whether that decline can be corrected with supplements, and what benefit that would bring, is a separate question.
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 if you use multiple substances.