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Photo of Shelly Albaum, site author

Shelly Albaum

Editor, Science of NAD

Important Disclosures

1. This is my personal website

All opinions are my own. Nobody writes here but me.

2. Supplements Are Not Medicines

Health Supplements like nicotinamide riboside are not intended to cure or treat any disease, condition, or illness.

3. No Medical Advice

I am a lawyer and a journalist, not a doctor, and I offer no medical advice. But I do follow the science, and I can bring to your attention

some interesting studies. You can read more about me here. And check with your physician -- your physician can look at this research, too.

4. Commercial Affiliations

I am a ChromaDex shareholder, and a marketing affiliate for Amazon and Rakuten. As a result, I will sometimes mention or recommend products that I endorse, like Tru Niagen, which I take every day. I may earn a small commission from qualifying purchases if you were referred directly from this site and completed a purchase. [Thank you!] You can read more about our advertising, privacy, and data collection policies here

400+ Published Studies on NAD Precursors

We have reviewed and organized 400+ studies considering the metabolism and effect of NAD precursors, including Niacin (NA), Niacinamide (NAM), Nicotinamide Riboside (NR), and Nicotinamide Mononucleotide (NMN), and even some next-generation precursors that are not yet available to consumers, like NRH.

Aging  |  ALS  |  Alzheimer's  |  Ataxia  |  Bioavailability  |  Bone  |  Blood  |  Brain  |  Cancer  |  Chemotherapy |   Circadian  |  COVID  |  Diabetes  |  Eye  |  Fertility  |  Glucose  |  Gut  |  Hearing  |  Heart  |  Immunity  |  Inflammation  |  Intestinal Barrier Dysfunction  |  Kidney  |  Liver  |  Lupus  |  Metabolism  |  Muscle  |  NAFLD  |  Neurons  |  Obesity  |  Pancreas  |  Parkinson's  |  Reproduction  |  Restless Legs (RLS)  |   Sepsis   |  Skin  |  Stem Cells  |  Vascular  |  Vision  |  Viral Infection

Woman aging gradually in three steps


Replenishing NAD levels is more likely to improve your healthspan than your lifespan -- the health of your years rather than the number of years. On the other hand, as one study points out, nicotinamide riboside has lengthened lifespan in every animal that has been tested. But we don't know yet in humans...

Photo of a Dissolving Pill being dropped into a glass of water


You're probably already eating a lot of NAD, because it's in all living things, and therefore in the plants and animals that you eat. The trick isn't getting NAD into your body, but getting it into your cells. Does NAD or its vitamin precursors reach your cells intact, or in a form that is likely to replenish NAD?

3D diagram of a human brain - blue light


Brain scientists are especially busy researching NAD precursors, because the brain is mostly made of neurons and early results are promising with respect to neuropathy and neurodegenerative disorders, including Alzheimer's, Parkinson's, ALS, and Ataxia.

Target superimposed over cancer cell

Cancer / Chemo

The impact of NAD metabolism on cancer is particularly complex, because cells need adequate NAD to protect themselves against DNA damage and cancer, and the immune system needs NAD to fight cancer cells, but some cancers rely on NAD levels to reproduce.

Woman awake or sleepless in bed

Circadian Rhythm

Proper NAD levels are necessary to sustain circadian rhythms. But the opposite also appears true, that disrupting circadian rhythms also disrupts NAD levels.

Photo of fingers holding a red grape next to a Blood Glucose Monitor
Diabetes / Pancreas /

Research involving rodents shows impress results for NAD replenishment on models of diabetes and glucose intolerance, but the results of human studies have not been nearly so clear...

Woman's Green Eye Close Up with Mascara

Eye / Vision

NAD levels are implicated in vision health, as well, including retinal degeneration and cataracts.

Gut microbiota - intestinal villi, bacteria, and microbes

Gut / Microbiota

At first, scientists worried that the gut microbiome might be degrading NAD precursors in unhelpful ways. But more recent research suggests that instead of just competing for NAD precursors, the. gut microbiome might be assisting with bioavailability. More remarkable still, NAD precursors may even be improving the condition of the gut microbiome that it can function better.

Hearing aid held near an ear


The research suggests that maintaining proper NAD levels can not only help prevent age-related or noise-induced hearing loss, but can even help recover from harm after the fact.

Drawing of the heart and circulatory system with red blood cells

Heart / Vascular

Many studies consider the impact of NAD levels on heart health, blood vessels, and the failing heart.

Immune system cells attacking a virus

Immunity / Lupus

NAD levels are implicated not only in viral disorders and chronic inflammation, but also autoimmune disorders, like Lupus.

Drawing of human kidneys


NAD levels not only impact kidney health, but even the development of healthy kidneys before birth while in the uterus.

Drawing of healthy and fatty livers, illustrating NAFLD Fatty Liver Disease

Liver / NAFLD

The liver is said to unhelpfully break down nicotinamide riboside into NAM, but the liver is itself a great consumer of NAD, and studies show that NAD replenishment can impact both alcoholic and non-alcohol fatty liver disease.

Swimmer swimming underwater


NAD is a primary mediator of metabolic activity, so many studies consider the nature of NAD metabolism, the different metabolic pathways, and the impacts of different NAD precursors.

Woman shoulder arm muscles


There is no doubt that NAD levels are implicated in muscle function, but here the results of human studies have been unclear, even though we have seen that muscle cells with that nicotinamide riboside pathway knocked out regenerate after damage more slowly than normal muscle cells.

neurons nerve cells electrical impulses


Nerve health impacts how we think and how we move, but replenishing NAD in nerve cells is peculiarly difficult because the metabolic pathway used by niacin is not active in neurons. And yet degenerative nerve disorders and dementia are when we most might most need to maintain our NAD levels.

Bacon Cheeseburger


Obesity disturbs NAD metabolism, and replenishing NAD helps mice recover from obesity, and improves their insulin resistance and glucose tolerance. But the effects in human studies are not as clear. 

Parkinsons Disease trembling hand holding glass of water

Parkinson's Disease

NAD replenishment won't cure Parkinson's Disease, but NAD metabolism does seem to be implicated, because even human studies suggest that NAD levels make a difference.

Photo of mom with laughing baby
Reproduction /

Pregnancy and postpartum are times of great metabolic disturbance, and the mouse studies show that maintaining NAD levels has an extraordinary impact not only on fertility and egg health before pregnancy, but also a long-term benefit for the pups of nursing moms that had adequate NAD. Whether these studies translate to humans remains to be seen.


Blood poisoning or sepsis occurs when the body's response to infection causes injury to its own tissues and organs. Sepsis can be life-threatening, and requires treatment with antimicrobials. Sepsis affects millions of people each year. Rodent studies have suggested that NAD replenishment may help with sepsis, perhaps by preventing oxidative stress. 

Skin - 450x250.jpg
Skin Aging /
Skin Cancer

UV radiation damages skin in several ways, including direct cell damage, gene mutations, oxidative stress, inflammation, suppression of antitumor immunity, and the creation of an “energy crisis” in skin cells which hinders effective DNA repair and can result in skin cancer.​ But replenishing NAD can protect your skin.

COVID virus viral infection
Viral Infection /

The innate immune system relies on NAD to fight infection, including viral infection, so it is no surprise that some viruses, including COVID, dramatically depress NAD levels when they strike, and that sustaining NAD levels can support the immune system's ability to fight back.

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