OK, first up—if you don't already know: NAD+ is coenzyme, or small molecule, found in all living cells, and it plays a vital role in energy metabolism and maintaining proper cell functioning. It's one of those wonderful things that helps us look and feel young and spry! But, like all good things, it doesn't last forever. In fact, your body stops producing it in the same quantities1, slowly decreasing with age.
How does the body make NAD+?
NAD+ is made by converting NAD+ precursors through a pathway. Think of precursors as "raw" ingredients. The primary precursor for NAD+ is vitamin B3, also called niacin2, a water-soluble vitamin. And niacin itself is actually just an umbrella term for three different compounds3 that each have similar activity in the body: nicotinic acid, nicotinamide (aka niacinamide), and nicotinamide riboside (NR).
You can think of pathways like conveyor belts in a factory. As the raw material moves along the conveyor belt, it is molded, stripped for parts, and tweaked until becomes a different molecule entirely. In this case, the new molecule is NAD+. The three pathways3 that NAD+ is made through is Preiss-Handler, Salvage, and De Novo Biosynthesis pathways.
And since this process declines with age, getting enough of these precursors becomes incredibly important. Let's look into the three NAD+ precursors here:
1. Nicotinic Acid
This is the most commonly known form of vitamin B3 and is sometimes called niacin4. Its primary use is helping manage cholesterol5 and aiding in overall heart health6. It's also readily available in foods like chicken breast and salmon, so you are able to maintain normal levels by adjusting your diet.
As far as a NAD+ precursor, however, nicotinic acid requires too high levels to see a significant change in NAD+. This is because it takes multiple steps to turn it into NAD+ along the pathways7. And these high levels might come with side effects, like skin flushing (meaning your skin might be blotchy or inflamed).
Our second form of B3 can also be found in our diets—usually in fish, poultry, nuts, legumes, eggs, and cereal grains. It is a more direct precursor to NAD+7, meaning the body can convert it faster. In studies, nicotinamide has been shown to help liver function, glucose metabolism, and overall health. However, research shows that it doesn't necessarily increase longevity in cells, like you might suspect with an NAD+ precursor. This is because nicotinamide can affect a class of proteins in our body called sirtuins, which we've learned contribute to longevity and healthy aging.
3. Nicotinamide riboside
Nicotinamide riboside, called NR, is a form of vitamin B3—and, when taken as a supplement, is a direct precursor for NAD+. While at the moment most of the research we have is done on animals, there several human studies seem that promising8 as well as north of 40 clinical trials in the works. For example, research has shown that NR as a supplement converts directly into9 nicotinamide mononucleotide (NMN), which is then converted into NAD—this process is much quicker than the other NAD precursors. Additional research has shown that helps support NAD levels in the body10. And this randomized, double-blind, placebo-controlled study found that taking the supplement daily helped individuals manage healthy weight11, which in turn helps longevity.
Naturally, it's found in trace amounts of milk but not enough to do anything substantial when drunk. Your best bet? A supplement. And so far, NR supplements have been tolerated at doses as high as 1,000 mg12 per day in trials, suggesting that for most it's likely safe.
"Supplementing with NR can support NAD+ to maintain your mitochondria and ATP levels. One recent randomized, double-blind, placebo-controlled, crossover clinical trial found regularly supplementing with 500 mg of NR twice daily effectively stimulates NAD+ metabolism in healthy middle-aged and older adults13.
Why NAD+ is so important for healthy aging.
As Ilene Ruhoy, M.D., Ph.D., an integrative neurologist and mindbodygreen health expert, told us, NAD+ is critical for helping our bodies respond to intrinsic and extrinsic stress and assaults, like inflammation and trauma. A few ways that having adequate levels of NAD+ can be beneficial for healthy aging, according to the available studies:
Additional ways to support NAD+ levels as you age.
Given how important NAD+ is for longevity and healthy aging, you're probably figuring out how to optimize it—and there are plenty of ways that you can support NAD+ levels. If you want a full breakdown, you can see our guide here, but here are a few of the top science-backed ways:
- Through balanced diets with the above precursors. Ingest nicotinamide and nicotinic acid through foods like poultry, fish, legumes, and smaller amounts in leafy dark greens.
- Supplementation. Since NR isn't readily available in our diet, you might consider a supplement. Two recent human trials on NR-containing supplements found that they both effectively increased levels of NAD+12 in the body, which is promising.
- Calorie restriction. Restricting calories17 (20 to 30% less than what you normally consume) and fasting have been shown to increase NAD+ levels. However, cutting your calories or fasting for prolonged periods of time isn't realistic or advisable for most people. There is some speculation that intermittent fasting diets and low-carb ketogenic diets18 might have a similar impact on NAD+ levels19—while being much more sustainable—but more research needs to be done.
- Use preventive measures. NAD+ declines with age but is also affected by environmental factors. Take, for example, sun damage. When your skin has UV damage, your body uses NAD+ to repair it. So by wearing safe SPF, you can stop UV damage from happening in the first place.
- Compounded medicines. These are currently under scrutiny by the FDA20, but many people get NAD+ prescribed through compounded pharmacies in the form of intranasal sprays or ionic patches. Some people receive NAD+ through IVs administered in a clinic setting.
The bottom line?
NAD+ is a coenzyme, or small molecule, found in all living cells, and it plays a vital role in energy metabolism and maintaining proper cell functioning. It is made in the body from precursors, all forms of vitamin B3: nicotinic acid, nicotinamide (aka niacinamide), and nicotinamide riboside (NR). And after looking at the available research, NR seems to be a promising way to support natural levels in the body to help your body age at the cellular level.
Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and Allure.com. In her current role, she covers all the latest trends in the clean and natural beauty space, as well as lifestyle topics, such as travel. She received her journalism degree from Marquette University, graduating first in the department. She lives in Brooklyn, New York.