Everything to Know About the New Celeb-Favorite Supplement NAD

By Oscar Hartzog

Oscar Hartzog

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There’s a good chance you’ve heard of NAD by now. Everyone from Joe Rogan to Jennifer Aniston and biohacker Bryan Johnson has sung the praises of the supplement — shorthand for nicotinamide adenine dinucleotide, an enzyme that helps boost cellular processes. But NAD is shaping up to be more than another celebrity fad. Growing evidence suggests that keeping NAD levels up might be one of the easiest ways to improve long-term health.

What Is NAD?

NAD (nicotinamide adenine dinucleotide) is a coenzyme involved in over 500 enzymatic processes in the body. It creates ATP (adenosine triphosphate, our cells’ fuel), powers the enzymes that repair damaged DNA, and protects against the stress behind inflammation and cardiovascular disease. Dr. Andrew Salzman, a Harvard-trained physician-scientist who specializes in NAD and DNA repair, calls it “the centerpiece of biology. It gives us our energy, it protects us against oxidants, and it saves us from cancer.”

Despite its importance to bodily functions, studies suggest that NAD levels begin dropping in our twenties and are roughly cut in half by age 50. That decline, says Salzman, can lead to everything from low energy and brain fog to metabolic disorders and impaired DNA repair. 

But restoring declining NAD levels isn’t as simple as taking NAD itself. Research has consistently shown that NAD molecules are poorly absorbed through the digestive tract and have difficulty crossing cell membranes because of their relatively large and complex structure. As a result, direct NAD supplementation has little ability to meaningfully raise intracellular NAD levels. Instead, scientists have found that the most effective way to increase NAD in the body is by supplying smaller precursor molecules — primarily NMN (nicotinamide mononucleotide) or NR (nicotinamide riboside). For a closer look at which formulas stand out, here’s a guide to the best NAD supplements of 2026.

Benefits of NAD

NAD use is connected with many potential positive outcomes, ranging from increased physical energy and a sharper mind to a lower risk of metabolic disorders, all of which can contribute to overall well-being and longevity. Below are a few of the most attractive and well-researched benefits of NAD.

DNA Repair and Longevity Every day, your DNA takes damage from UV exposure, toxins, and simple cellular replication. PARP — the enzyme that fixes it — runs on NAD. “Low NAD means no DNA repair. Mutations. Ultimately, malignancy,” Salzman explains. NAD also activates sirtuins, proteins sometimes called longevity genes, which regulate inflammation, stress response, and metabolic function. 

Sleep Health Because NAD is involved in many of the body’s core regulatory systems, its influence extends beyond cellular repair and metabolism to processes that affect everyday well-being, according to numerous studies, such as sleep. Adequate NAD also supports circadian rhythm regulation: Multiple clinical trials have shown that NMN supplementation meaningfully improves sleep quality.

Brain Fog and Cognitive Support Brain fog is one of the most-searched health complaints of 2026, and there’s growing evidence that NAD depletion is a factor. “Low NAD levels impair mitochondrial function, which means your brain doesn’t get the energy it needs,” says Salzman. “This leads to brain fog, slower thinking, and cognitive decline.” Dr. Mark Hyman, a family physician and best-selling author (who takes NAD supplements himself), describes it as essential for mitochondrial activity, inflammation regulation, and DNA repair — all of which directly affect cognition.

Metabolic Function and Weight Both aging and high-fat diets reduce NAD levels. A clinical trial in Science found that women with prediabetes taking NMN for 10 weeks showed improved ability to process glucose. Salzman’s own research, published in Nature, showed that diabetes triggers an NAD drop, which then drives the vascular complications and insulin resistance that make the disease destructive. 

Athletic Recovery and Muscle Health A recent trial of amateur runners published in the Journal of the International Society of Sports Nutrition found NMN supplementation improved VO2 and VO2max through enhanced oxygen utilization in skeletal muscle. On the cellular level, NAD is required for muscle fiber expansion and recovery. 

Menopausal and Ovarian Health For women specifically, NAD has been shown to support menopausal health by managing the inflammation that accelerates with declining estrogen, and research suggests it can improve ovarian reserves. 

Skin Health For skin elasticity, NMN increases hyaluronic acid production, which is critical for maintaining moisture and the skin’s barrier function, improving hydration, and UV damage repair.

Hair Health Many people turn to hair growth methods and combat gray hair at the cellular level. Findings from a 2023 study suggest that NMN supplementation may help reverse hair follicle shrinkage, thinning hair, and reduced hair density, demonstrating effectiveness similar to minoxidil.

Mold Detoxification Research indicates that enzymes that rely on NAD play a role in transforming harmful mycotoxins into less toxic substances, thereby supporting the body’s built-in defense systems.

How to Increase NAD Levels Safely

Here’s what most people miss: You can’t take an NAD pill and raise your cellular NAD levels. Clinical literature is clear — NAD is poorly absorbed by the gut and can’t cross cell membranes effectively. 

The good news? There are NAD precursors that can increase levels: Primarily NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside), which the body more easily absorbs and converts. NMN is one step closer to NAD in the conversion chain, but both are clinically proven to raise NAD levels. The products labeled simply “NAD” — nasal sprays, sublingual drops, liposomal formulas — are capitalizing on search trends, not science.

One more variable worth knowing: the enzyme CD38 actively destroys NAD and increases as we age. Some advanced supplement formulations include CD38 inhibitors like resveratrol and hydroxytyrosol alongside NMN, addressing depletion at the source. Wonderfeel Youngr NMN takes this approach: 900mg NMN combined with those antioxidants in a third-party tested, cGMP-certified formula developed by Salzman.

Lifestyle Still Matters

Aerobic exercise, intermittent fasting, quality sleep, and limiting alcohol all support NAD biosynthesis. In other words, a healthy lifestyle will significantly improve the positive effects of NAD precursors. Most researchers suggest combining these behaviors with a well-dosed precursor supplement for the best results.

Safety and Side Effects

Another reason for NMN’s explosion in popularity is that it appears very safe, as well as efficacious. A 2022 safety evaluation found 1,250 mg of NMN daily for four weeks to be safe with no adverse effects. In another trial, conducted by Harvard, participants took 2,000 mg daily and found benefits — lower LDL, reduced body weight, lower blood pressure — without harm. Concerns about liver or kidney stress aren’t supported by current evidence at typical doses. The more relevant caution is product quality: dosage, purity, and third-party testing vary widely.

Wonderfeel Youngr NMN

$88

Our favorite NAD-booster right now is Wonderfeel’s Youngr NMN. It’s a potent 900 mg NMN dose aligned with expert guidance and boasts antioxidant support to mirror NAD’s real‑world biology.

Frequently Asked Questions

How long does it take to feel the benefits of NAD? While NAD levels may begin increasing soon after taking a precursor such as NMN, noticeable benefits usually develop gradually because the process works at the cellular level.

Some people report improvements such as an increase in physical energy or reduced inflammation within the first few weeks. More noticeable benefits, such as cognitive clarity, workout recovery, or metabolic support, often begin to emerge after about three months of consistent use. Changes related to skin health or other visible markers of aging can take longer, sometimes appearing after several months to a year, since these effects depend on longer-term improvements in cellular function.

Can I increase NAD naturally? It’s possible to support NAD levels naturally through healthy lifestyle habits. Regular exercise can help stimulate NAD production because physical activity increases the body’s need for cellular energy. Diet can also play a role — foods rich in vitamin B nutrients, such as fish, eggs, mushrooms, leafy greens, whole grains, and avocados support the metabolic pathways involved in NAD production, while fermented foods like yogurt, kefir, kimchi, and sauerkraut contain small amounts of NAD-related compounds. Certain metabolic approaches, including intermittent fasting or ketogenic-style diets, may also influence NAD-dependent processes by changing how the body uses energy. Heat exposure from activities such as sauna sessions, hot tubs, or heated pools may further activate cellular pathways that rely on NAD-dependent enzymes. Together, these habits may help support healthy NAD metabolism, although researchers are also studying NAD precursors like NMN and NR as more direct ways to increase NAD levels as they decline with age.

What does NAD do for women’s health? NAD plays a central role in many aspects of women’s health, particularly in aging, hormone function, fertility, and sexual wellness. NAD supports cellular energy production, which is essential for tissues with high energy demands like the ovaries, brain, and reproductive system. One of NAD’s most critical roles is in DNA repair. In women, this is especially important because eggs are formed at birth and must remain healthy for decades. NAD fuels enzymes that constantly monitor and repair DNA damage, helping maintain the integrity of these cells over time. NAD also contributes to hormonal and reproductive health by supporting ovarian function. It helps provide the energy required for egg maturation and ovulation, both of which are energy-intensive processes.

What is NAD IV therapy and how does it work? NAD IV therapy is a treatment that delivers NAD directly into the bloodstream through an intravenous (IV) drip and is marketed as a fast way to boost NAD levels. However, while IV therapy bypasses digestion, NAD molecules still face challenges entering cells, where they are actually needed. Research suggests that much of the infused NAD may be broken down or excreted before it can be fully used by the body. As a result, the effectiveness of NAD IV therapy remains unclear, with limited and mixed clinical evidence. Current research indicates that NAD precursors like NMN and NR in oral form are more effective at increasing NAD levels because they are easier for cells to absorb and convert.