Everything You Need to Know About NAD and NAD+ Supplements

NAD supplements have quickly become one of the most talked-about tools in the longevity space—especially for women navigating midlife. While the science behind NAD isn’t new, it’s finally gaining the mainstream attention it deserves. That’s because NAD levels decline naturally with age—and the drop tends to accelerate during perimenopause and menopause. This decline may impact your body's ability to repair faulty cells, maintain a healthy metabolism and a well-tuned circadian rhythm—all of which may contribute to fatigue, brain fog, weight gain, and other signs of aging that many women begin to notice in their 40s.

First, let’s back up and cover a few basics: Short for nicotinamide adenine dinucleotide, NAD is a coenzyme found in every cell of the body. It plays a critical role in cellular energy production, DNA repair, and overall metabolic function. As NAD levels fall, these essential processes slow down, which has been linked to signs of aging, including cognitive decline and metabolic disease. Some evidence suggests this drop may begin around age 45—coinciding with the transition into perimenopause.

That’s where supplements come in. Boosting NAD and NAD+ levels—either directly or through their precursors like NMN, NR, or NADH (which we’ll cover below)—may help restore cellular function, support healthier aging, and protect against the stressors that become more prominent during hormonal shifts.

“NAD supplements may help restore levels in the body, which is why interest has exploded in recent years,” says Kathleen Jordan, MD, Chief Medical Officer at Midi Health.

Read on to learn more about the potential benefits of NAD supplements—and how they may support energy, metabolism, and longevity.

What Is NAD?

Allow us to take you back to middle school science class for a minute. If you remember learning about mitochondria, then you know that these organelles are the “powerhouses” of your cells. They generate the energy needed to make your body function as it should. NAD is important because it’s known to regulate mitochondrial signaling. In fact, NAD helps hundreds of enzymes in your cells do their jobs:

• Mending DNA damage
• Reducing inflammation
• Improving cell signaling

While this may sound very technical, it all ladders up to one clear advantage: boosting reduced NAD levels may improve overall health and slow aging. “The importance of NAD and cellular health has a long history in the longevity space,” says Dr. Jordan.

Types of NAD Supplements

There are several types of NAD supplements you might see on the market—NAD+, NADH, NR, NMN—all of which can help your body boost its own NAD production. While the differences are quite technical and boil down to the mechanisms used to boost NAD, here’s how to separate them at a high level:

• NAD+: This supplement works by helping your cells make energy from food, primarily sugar and fats.
• NADH: This form delivers energy to parts of cells that make ATP (the energy your body uses). This is what actually powers things in your cells.
• Nicotinamide Mononucleotide (NMN or NM): This is a direct precursor to NAD+— your body can turn NMN into NAD+ pretty quickly.
• NR (Nicotinamide Riboside): Like NMN, this is another NAD+ precursor. NR gets turned into NMN first, then into NAD+

NAD supplements are available as a pill, powder, liquid or IV injection. You can also increase levels of NAD through lifestyle factors like getting regular exercise and restful sleep, as well as eating a healthy diet with foods containing niacin (vitamin B) found in meat, fish, dairy products and certain vegetables, such as cabbage and cucumbers. 

Benefits of NAD Supplements

If you’ve been hearing more and more about NAD supplements these days, it’s important to understand the research—what we know and what we may be able to infer about NAD’s benefits based on where the science stands. Like any supplement, it’s best to work with a healthcare professional, like a Midi clinician, to determine if it’s right for you. 

Anti-Aging and Longevity

Aging is a complex process, but a lot of it boils down to cellular aging, and research shows that declining levels of cellular NAD plays a role in accelerated aging and ultimately longevity. 

However, the opposite has also been shown to be true: There’s evidence—although primarily in animal studies—that increasing NAD levels may slow aging. That’s because NAD coenzymes impact pathways in the body that modify aging, according to a 2021 UK study that included human and animal data. 

Another paper in Ageing Research Reviews found that NAD may “replenish NAD levels in aged tissues and exhibit beneficial effects against aging and aging-related diseases. Most importantly, boosting NAD metabolism has been shown to extend the lifespan of various organisms,” including mice. 

“By increasing NAD activity, you don’t get the same rate of cell death, and it can help repair DNA,” explains Dr. Jordan. “So there’s a theoretical link that it could prevent cancers because you won’t get aberrant cell growth that might lead to premature death.” 

Improved Cognitive Function

Mitochondrial damage—in part due to a lack of NAD—has been shown to increase neuroinflammation. A strong body of research has proven that too much inflammation can lead to all sorts of adverse health outcomes, including cognitive ones. Tamping down inflammation has the opposite effect. 

While experimental animal studies suggest that treatments involving NAD may decrease oxidative stress, neuroinflammation, and positively impact the expression of growth factors and mitochondrial function, various studies are still underway to investigate the potential impact on memory, focus and mental clarity in humans. 

Enhanced Energy Levels

NAD is vital for the function of enzymes involved in the production of adenosine triphosphate (ATP), which is the primary energy carrier in cells that is made by mitochondria. Without enough NAD, your cells can’t generate the energy needed for various physiological processes, causing fatigue, among other issues. 

Boosting NAD levels has been shown to improve ATP synthesis, which has several benefits including:

• Improving your body’s ability to convert the food you eat into usable energy
• Promoting overall cellular function
• Optimizing energy production that affects how efficiently you burn through your energy stores

Better Metabolic Health

Metabolism doesn’t just refer to how fast your body burns calories. It’s also what helps regulate your blood sugar, insulin and cholesterol levels. Some evidence suggests that increasing NAD may lower the risk for obesity, metabolic syndrome and the conditions they can cause, including heart disease, type 2 diabetes and stroke, but the science is mixed with some research showing no improvements related to insulin resistance.

The mechanism is still unclear, but one oft-cited study of women who were overweight or obese and also had prediabetes found that NAD supplementation with nicotinamide mononucleotide (NM), an NAD precursor, for 10 weeks improved insulin sensitivity. Preliminary research also suggests that boosting NAD may improve body composition.

Support for DNA Repair and Cellular Health

We’ve touched on the role of NAD in supporting DNA repair and cellular health. But let’s dig into a bit more research here. A review of studies in the Journal of Biological Chemistry reported that NAD impacts pathways that are involved in gene preservation and expression, as well as how well your body responds to DNA damage. Think of it as one of the safeguards of your DNA, preventing everything from aging to diseases from setting in.

Doctor-Recommended NAD Supplements

At Midi, we primarily recommend NMN and NR, since these precursors appear to be more effective in oral form than NAD or NAD+:

NR (Nicotinamide Riboside)

• Typical Dose: 300–500 mg/day; some use up to 1 g/day for more robust increases in NAD+ levels
• Suggested Brands: Tru Niagen (Niagen is a patented form of NR) and Thorne ResveraCel (includes NR plus additional antioxidants)

NMN (Nicotinamide Mononucleotide)

• Typical Dose: 250–500 mg/day (up to 1 g/day if well-tolerated)
• Suggested Brands: ProHealth and Alive by Nature (offers sublingual forms for potentially enhanced absorption)

How to Choose the Best NAD Supplement

As with any supplement, it’s important to look for one that has independent, third-party research supporting its formulation, efficacy and safety. Some good ones include U.S. Pharmacopeia (you’ll see it as USP or USP Verified) and NSF International. As with anything you take for your health, though, it’s a good idea to consult with your healthcare professional, like a Midi clinician, before you go shopping.

Suggested Dosages of NAD Supplements

There are no recommended dosages for NAD or its precursors, says Dr. Jordan. Some trials have looked at supplements that offer between 250 and 1,000 mg per day—which is obviously a big range. 

“But one thing to know is that NAD has been around long enough—and people have been supplementing with it for decades—that it’s clear that NAD is safe. And while you want to be reasonable about the amounts you take, there aren’t cases of toxicity,” says Dr. Jordan. 

Does NAD Really Work?

Because NAD is a supplement, it’s not regulated by the FDA and claims around efficacy don’t have to be proven (which is required of prescription medications). While the potential impact of boosting your NAD levels with supplements are still being researched, there is a firm understanding that NAD-boosting supplements are a safe way to address age-related decline in NAD that has shown benefit in early studies across various consequences of aging.

While the potential impact of boosting your NAD levels with supplements are still being researched, there is a firm understanding that NAD boosting supplements are a safe way to address age-related decline in NAD that has shown benefit in early studies across various consequences of aging.

The big thing to keep in mind about NAD: It takes time to work, so patience is key. “The challenging part is that it doesn’t immediately make you feel great,” says Dr. Jordan. “You take melatonin and it makes you feel more zen. Or you take hormone therapy and it helps you sleep, feel more vibrant and makes your skin and hair look better. With NAD, it’s helping you at a cellular level, but there’s no immediate boost. You have to have faith that it’s working for you.” 

Potential Side Effects and Precautions of NAD Supplements

Some minor side effects that could be tied to NAD supplementation include:

• Headache
• Diarrhea
• Nausea
• Flushing
• Rashes
• Abdominal discomfort
• Digestive issues

But again, the safety of NAD is pretty sound. It is possible that interactions could occur with certain medications, including insulin, blood thinners, and chemotherapy. Be sure to share any supplements you take with your healthcare providers and don’t add new ones without consulting first to reduce the risk of side effects.

How to Maximize NAD Supplement Benefits

Because regular exercise and a healthy diet can naturally support NAD production, making these lifestyle changes in addition to taking a supplement could give you an extra boost. 

Research shows that physical activity spurs NAD synthesis in both old and young muscle tissue. And, in terms of nutrition, there’s evidence that eating a high-fat, high-sugar diet can interfere with your cellular NAD levels and, in turn, mitochondrial function. A healthy diet with plenty of vegetables and lean protein may have the opposite effect.

Key Takeaways

• NAD has been shown to support healthy aging and longevity.
• It may also boost cognitive function, energy levels, and improve insulin sensitivity.
• NAD can be taken as a pill, a powder, or IV.
• More large-scale research in humans is needed, but there’s plenty of research in animals to show the potential promise of NAD in promoting health and longevity. And it’s generally considered safe for humans to take.

Frequently Asked Questions (FAQs)

What does the NAD supplement do?

NAD is a coenzyme that’s found in every cell in your body. Levels naturally decrease with age—notably as you reach menopause. So supplementing with NAD or one of its precursors (NAD+, NADH, NR, NMN) can boost your stores and protect you from DNA damage.

What are the downsides of NAD?

Experts consider NAD generally safe for most people. There is no hard-and-fast amount that’s recommended, but upwards of 1,000 mg a day appears to be safe. The side effects also are minimal, but you should consult your healthcare provider before adding it to any other medication or supplements you’re already taking.

Is NAD just vitamin B3?

Not exactly. B3 is a vitamin that your body uses to convert NAD+.

What is the best form of NAD to take?

There’s some evidence that the most beneficial form of NAD may be nicotinamide riboside (NR) thanks to its bioavailability—and therefore its ability to increase NAD levels.

Are there any dangers taking NAD supplements?

Some mild side effects and interactions have been noted, but for the most part, no, they aren’t any major dangers to taking NAD supplements.