How Is NAD+ Made? Where NAD+ Comes From in the Body

Your body makes NAD+ in three ways: from the amino acid tryptophan, from niacin (vitamin B3) in food, and, most of all, by recycling the NAD+ it has already used. The recycling route turns nicotinamide into NMN and NMN into NAD+, which is why NMN and NR are studied as NAD+ boosters. NAD+ levels fall with age, and in human skin samples they dropped steadily from newborns to adults in their 70s.

Key Takeaways

• NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that more than 400 enzymes need, more than for any other vitamin-derived coenzyme (NIH ODS: Niacin).
• It is made from tryptophan, from niacin in food, and by recycling nicotinamide through NMN (Covarrubias et al., 2021).
• About 60 mg of tryptophan makes 1 mg of niacin, and adults need 14 to 16 mg of niacin equivalents a day (NIH ODS: Niacin).
• In skin samples from 49 people aged 0 to 77, NAD+ fell with age in both men and women (Massudi et al., 2012).
• In healthy older men, 250 mg of NMN a day for 12 weeks raised blood NAD+ and was well tolerated (Igarashi et al., 2022).

What Is NAD+ Made Of?

NAD+ stands for nicotinamide adenine dinucleotide. As the name says, it is two nucleotides joined together through their phosphate groups: one carries adenine, the same base found in ATP, and the other carries nicotinamide, a form of vitamin B3. The nicotinamide end is the working part: it picks up and hands off electrons, turning NAD+ into NADH and back again as cells turn food into energy. Our guide to NAD+ vs NADH explains that swap, and what NAD+ is and why it declines covers the basics.

NAD+ is also used up, not just recycled, by enzymes such as sirtuins and PARPs, which take part in DNA repair and other cell maintenance (Covarrubias et al., 2021). That is why the body has to keep making it.

How Is NAD+ Made? The Three Pathways

Pathway	Starts from	What to know
From scratch (de novo)	Tryptophan, an amino acid in protein foods	A long chain of steps; about 60 mg of tryptophan yields 1 mg of niacin
From niacin (Preiss-Handler)	Nicotinic acid, one form of vitamin B3	Turns dietary niacin into NAD+ in three steps
Recycling (salvage)	Nicotinamide, released when NAD+ is used	Nicotinamide becomes NMN, and NMN becomes NAD+; nicotinamide riboside (NR) joins here too

All three routes end in NAD+ (Covarrubias et al., 2021). In most tissues the recycling route does most of the daily work: each time an enzyme uses NAD+ and releases nicotinamide, the cell can rebuild NAD+ from it through NMN. That step is why NMN is described as the direct precursor of NAD+; see NMN vs NAD+.

Where Does NAD+ Come From in Your Diet?

Food does not supply much NAD+ itself, but it supplies the raw materials. Niacin comes from poultry, beef and fish (about 5 to 10 mg per serving) and from nuts, legumes and grains (about 2 to 5 mg), and many breads and cereals in the United States have added niacin. Adults need 16 mg of niacin equivalents a day (men) or 14 mg (women), where one niacin equivalent is 1 mg of niacin or 60 mg of tryptophan. The upper limit for supplemental niacin is 35 mg a day (NIH ODS: Niacin).

Exercise, sleep and eating patterns also affect NAD+; our guide to how to increase NAD+ naturally covers what research shows for each.

Why NAD+ Declines With Age

Aging is accompanied by a gradual fall in NAD+ in many tissues, in rodents and in humans (Covarrubias et al., 2021). In one human study, researchers measured skin samples from 49 people, from newborns to age 77. NAD+ fell with age in both men and women, while DNA damage rose. The authors suggested that, as DNA damage builds up, repair enzymes called PARPs use more NAD+, leaving less for everything else (Massudi et al., 2012). Our guide to NAD+ and DNA repair explains this in more depth.

Where NAD+ Supplements Fit

Supplements aim to feed the recycling pathway or supply NAD+ directly:

• NMN: one step from NAD+. In a placebo-controlled trial in healthy older men, 250 mg a day for 6 or 12 weeks raised blood NAD+ and was well tolerated (Igarashi et al., 2022).
• NR: another precursor that enters the recycling route; see NMN vs NR.
• Niacin: feeds the Preiss-Handler route; supplemental niacin above 35 mg a day can cause flushing.
• NAD+ itself: delivered as a nasal spray, IV or injection; see NAD+ boosters explained.

If you take NMN, our guide to NMN and TMG explains why TMG is often added.

Where Our NAD+ Products Fit

Our NAD+ Nasal Spray contains NAD+ and alkaline water and nothing else, in three strengths: 35 mg, 100 mg or 170 mg per 2-spray serving, with 30 servings per bottle. Our Enhanced NMN capsules feed the recycling pathway with 750 mg of NMN per 2-capsule serving, plus 200 mg of trimethylglycine, 200 mg of resveratrol, 100 mg of pterostilbene and 750 mcg of methyl B12. Many people use both: the spray as needed, and the capsules every morning. Read more on our NAD+ ingredient page and our cellular energy and mitochondria guide.

Frequently Asked Questions

How is NAD+ made in the body?

From tryptophan, from niacin, and by recycling nicotinamide through NMN back into NAD+. In most tissues, recycling does most of the daily work.

Where does NAD+ come from?

Your cells make it. Food supplies the raw materials, mainly niacin and tryptophan from protein foods, nuts, legumes and fortified grains.

What is NAD+ made of?

Two nucleotides joined by phosphate groups: one carries adenine, the other carries nicotinamide, a form of vitamin B3.

What is the precursor to NAD+?

NMN is the direct precursor in the recycling pathway. Nicotinamide, NR, niacin and tryptophan are earlier starting points.

Why does NAD+ decrease with age?

Enzymes that use NAD+, such as PARPs involved in DNA repair, appear to consume more of it as damage builds up, and levels fall in many tissues with age.

Can you get NAD+ from food?

Not much directly. Food mostly provides niacin and tryptophan, which your body converts. Adults need 14 to 16 mg of niacin equivalents a day.

Is NMN or NAD+ better?

They do different jobs: NMN is a building block your cells turn into NAD+, while a NAD+ nasal spray supplies the finished molecule. See NMN vs NAD+ for the details.

What is the difference between NAD+ and NADH?

NADH is NAD+ carrying electrons. Cells swap between the two as they turn food into energy.

Sources

• Covarrubias AJ, Perrone R, Grozio A, Verdin E. NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 2021. https://pubmed.ncbi.nlm.nih.gov/33353981/
• National Institutes of Health, Office of Dietary Supplements. Niacin: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/
• Massudi H, et al. Age-associated changes in oxidative stress and NAD+ metabolism in human tissue. PLoS One, 2012. https://pubmed.ncbi.nlm.nih.gov/22848760/
• Igarashi M, et al. Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men. npj Aging, 2022. https://pubmed.ncbi.nlm.nih.gov/35927255/

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.