NAD+ Supplements and Longevity: What the NOPARK Trial Changes

NAD+ boosters are among the best-selling longevity supplements. The idea is appealing: levels of NAD+, a molecule every cell needs for energy and repair, fall with age in many tissues, so topping them up might help cells behave younger. In October 2026, a phase 3 trial published in JAMA put one of the most popular NAD+ precursors, nicotinamide riboside (NR), to a year-long test in people with early Parkinson’s disease. It did not work, and on some measures patients did slightly worse than on placebo. Here is what the trial found, what it does and does not tell us about healthy aging, and how to think about NAD+ supplements today.

What NAD+ is and why it became a longevity target

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell. It helps mitochondria turn food into usable energy, and it fuels enzymes involved in DNA repair and stress responses. In laboratory research, declining NAD+ has been tied to several hallmarks of aging, including mitochondrial dysfunction and deregulated nutrient sensing. You can explore those hallmarks on our Science page.

NAD+ itself is not well absorbed, so supplements supply precursors that the body converts into NAD+. The two best known are nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). See how they compare with other approaches on our Therapeutics page.

What earlier human trials showed

Healthy middle-aged and older adults

In a randomized, double-blind, placebo-controlled crossover trial with two six-week periods, NR was well tolerated and effectively stimulated NAD+ metabolism in healthy middle-aged and older adults (Martens et al., Nature Communications 2018). The authors suggested future trials look more closely at blood pressure and arterial stiffness.

Prediabetes

In a 10-week randomized trial in postmenopausal women with prediabetes and overweight or obesity, NMN increased muscle insulin sensitivity measured with the gold-standard clamp technique, along with muscle insulin signaling (Yoshino et al., Science 2021).

Parkinson’s disease, phase 1

In the NADPARK trial, 30 people with newly diagnosed, untreated Parkinson’s disease took 1,000 mg of NR or placebo for 30 days (Brakedal et al., Cell Metabolism 2022). NR was well tolerated and raised brain NAD+ levels, though the increase varied between people. Those whose brain NAD+ rose showed changes in brain metabolism that were associated with mild clinical improvement. That result set the stage for a much larger test.

Taken together, these studies showed that NAD+ precursors can raise NAD+ and are well tolerated in the short term. They were small and short, and none showed a change in hard aging outcomes.

The NOPARK trial: design and results

NOPARK was a randomized, double-blind, placebo-controlled phase 3 trial run at 11 centers in Norway (Brakedal et al., JAMA 2026). It enrolled adults diagnosed with Parkinson’s disease within the previous two years, with early-stage disease confirmed by dopamine transporter imaging and stable dopaminergic treatment. Between May 2020 and June 2024, 410 people were randomized to NR 500 mg twice daily or matching placebo for 52 weeks.

The primary outcome was the change in the total MDS-UPDRS score (parts I to III), a standard Parkinson’s rating scale where higher scores mean more severe disease. Among the 393 people in the primary analysis, the mean age was 65.6 years and 34% were female.

• Primary outcome: the total score rose by 2.45 points with NR and fell by 0.27 points with placebo. The adjusted mean difference was 2.72 points (95% CI 0.47 to 4.98; P = .02), favoring placebo.

• Secondary outcomes: four of five key secondary outcomes showed no difference. Nonmotor symptom burden worsened more with NR (difference 4.22 points; 95% CI 1.07 to 7.37).

• Safety: serious adverse events occurred in 8.3% of people taking NR and 14.1% of those taking placebo.

The investigators concluded that the findings do not support NR as a disease-modifying treatment for Parkinson’s disease. Read our short summary in Research Updates.

How to read the result

• The effect was small. The 2.72-point difference was below the 5.2-point threshold the investigators defined as clinically important worsening. The clearest message is no benefit, rather than major harm.

• Parkinson’s disease is not aging. A trial in a neurodegenerative disease does not directly test whether NR slows aging in healthy people.

• Raising a biomarker is not the same as helping patients. Earlier work showed NR raises NAD+, including in the brain. In this larger and longer trial, that did not translate into better clinical outcomes.

• It was a well-designed test. A year of treatment, placebo control, imaging-confirmed diagnosis and a prespecified primary outcome make this one of the more informative NAD+ trials to date.

Where this leaves NAD+ supplements for healthy aging

In the US, NR and NMN are sold as dietary supplements. They are not FDA-approved to treat or prevent any disease, and no regulator has approved any product for aging. The human evidence today shows that these precursors raise NAD+ and are well tolerated in short studies, that one small trial found improved muscle insulin sensitivity, and that a year-long phase 3 trial in early Parkinson’s disease found no benefit.

That is a thin base for long-term use. Supplement products are not reviewed by the FDA for effectiveness before they are sold. If you take an NAD+ booster, or are thinking about one, the right first step is a conversation with a physician who knows your history, your medications and your goals. That physician-first principle applies to every therapy on our Therapeutics page.

What would settle the question

1. Longer randomized trials in healthy older adults with function-based endpoints such as strength, walking speed, cardiovascular measures and cognition.

2. Validated biomarkers of aging that regulators accept as trial endpoints, the goal of programs such as ARPA-H PROSPR. Browse our Research Updates for the latest on aging clocks.

3. Studies that identify who, if anyone, has a meaningful NAD+ shortfall that responds to supplementation.

Bottom line

NAD+ biology is real and important, but NAD+ supplements remain unproven for healthy aging. A large, year-long test of NR in early Parkinson’s disease found no benefit. Living longer only matters if you live youthful, and the best-supported foundations of a youthful healthspan are still cardiorespiratory fitness, strength training, sleep, nutrition and good medical care.

FAQ

Do NAD+ supplements slow aging?

No human trial has shown that NAD+ supplements slow aging or extend lifespan. Short studies show they raise NAD+ levels and are well tolerated.

Did nicotinamide riboside fail in the NOPARK trial?

Yes. After 52 weeks, NR did not improve outcomes in early Parkinson’s disease, and total symptom scores worsened slightly more than with placebo.

Are NR and NMN FDA-approved?

No. They are sold in the US as dietary supplements and are not approved to treat or prevent any disease, including age-related disease.

Should I take an NAD+ booster?

That is a decision to make with a physician who knows your health history. The human evidence for healthy-aging benefits is limited, and supplement quality varies.

Stay ahead of the evidence

Get the evidence without the hype. Join the Longevity Brief for physician-reviewed research updates, or book a consultation with Dr. Farhan Tahir at youthfulmedicine.com.

This article is for educational purposes only and is not medical advice. It does not create a doctor-patient relationship. Talk with your own physician before starting, stopping or changing any medication or supplement.