Most people first hear about NAD in wellness ads or on social media. The truth is simpler. NAD (nicotinamide adenine dinucleotide) is a helper molecule that lets our cells turn food into energy and repair damage. Levels of NAD tend to fall with age. NAD supplements try to raise those levels. This guide explains what NAD supplements are, what we know from human studies, and where claims go beyond the evidence.
What are NAD supplements and how they work
NAD is a coenzyme. A coenzyme is a small molecule that helps enzymes do their job. Inside cells, NAD switches between two forms, NAD+ and NADH, to move energy around. NAD is also used by repair enzymes that fix DNA and keep cell clocks on time.
Most products sold as NAD supplements do not contain NAD itself. They contain precursors, which are building blocks the body uses to make NAD. The two most common are nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). When you swallow NR or NMN, your body can convert them into NAD. Some clinics offer NAD by intravenous (IV) drip, but the science base for IV infusions is thin compared with oral precursors.
If you want a deeper overview before reading on, see our plain-language explainer, where we show that NAD supplements raise NAD in the body and why broad health gains are not established yet.
Do NAD supplements increase NAD in humans?
Early human studies show that certain NAD precursors raise NAD in blood. A controlled trial found that oral nicotinamide riboside increased markers of NAD metabolism in healthy adults. Other trials report that nicotinamide mononucleotide increased muscle insulin sensitivity in women with prediabetes, although this was a specific group and not proof of general benefits.
Across studies, the size of the NAD rise varies by dose, product, and person. Reviews note that NAD levels appear to decline with age in some tissues, which is one reason researchers test precursors in older adults.
Potential benefits of NAD supplements: signals and limits
What looks promising
Small human studies suggest possible benefits in select cases, such as improved insulin signaling in muscle after NMN in people with prediabetes. Some trials with NR report changes in blood markers tied to inflammation or liver fat, but findings are mixed from study to study.
What is not yet proven
Claims that NAD supplements make people live longer, sharpen memory for most adults, or prevent chronic disease are not yet supported by strong human evidence. Animal studies are encouraging, but human trials large enough to measure health events over years are missing. That is why our explainer stresses that lifestyle counts far more than genetics for health and longevity: daily habits move risk more than any single supplement we can buy today.
Risks, side effects, and who should avoid NAD supplements
Short studies in adults find NR and NMN are generally well tolerated. Reported side effects are usually mild, such as nausea or flushing, and often dose related. People with liver disease, those on blood thinners or chemotherapy, and people who are pregnant or breastfeeding should speak to a clinician before use. If you choose to try a product, do not exceed the label dose, and avoid mixing with other “anti-aging” stacks without medical advice.
Because supplement rules differ from drug rules, product quality can vary. Look for third-party testing, clear labeling, and a brand that shares its ingredient source and dose. If a clinic offers NAD IV drips, ask what evidence supports the use in your case, and the risks and costs compared with oral precursors.
Forms and doses: pills, IV, and lifestyle ways to raise NAD
Pills and powders
Most research uses capsules of NR or NMN. Typical study doses range from about 250 mg to 1,000 mg per day for short periods. Higher doses have been used in trials under medical oversight.
IV infusions
NAD IV drips deliver NAD or precursors directly into a vein. Some people report quick effects such as alertness, but published evidence is limited, and infusions are costly. Until stronger data exist, oral precursors have the more solid research base and are easier to compare across brands.
Everyday habits that support NAD
Good sleep, regular exercise, and balanced food choices support the body’s energy pathways that use NAD. Gentle, repeatable activity like walking and strength work help many people keep weight and blood sugar in check; see why walking is the simplest way to lose fat and keep it off.
Limitations and quality of evidence
Most NAD supplement studies in humans are small and short. Many measure blood NAD or lab markers, not hard outcomes such as fewer heart attacks or better memory years later. Some authors or funders have ties to companies that make NAD products. Independent, longer trials in diverse groups are needed before making broad claims.
Nature Communications – Nicotinamide riboside is uniquely and orally bioavailable in mice and humans – 2016
A clinical pharmacokinetics study showed that oral nicotinamide riboside raised human blood NAD+ and related markers in a dose-dependent way. Evidence type: human trial.
Science – Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women – 2021
In a randomized controlled study, NMN improved muscle insulin sensitivity and signaling in overweight women with prediabetes. Evidence type: randomized controlled trial (specific group).
Frontiers in Aging – Nicotinamide adenine dinucleotide in aging biology – 2023
A peer-reviewed review summarizes that NAD+ levels decline across life and may contribute to age-related conditions. Evidence type: narrative review.
GQ – NAD supplements promise to improve energy, metabolism, and longevity – 2025
A magazine explainer describes what NAD is, how supplements are used, and why expert opinions differ on IV versus oral forms. Evidence type: reputable secondary source.
This article is for general information and does not replace medical advice.
0 Comments