Anti-ageing supplements are everywhere, from advertising campaigns to social media feeds. Promising everything from increased energy to a longer life, they come in many forms, from powders containing multiple ingredients to single-nutrient capsules.
Author
- Justin Roberts
Professor of Nutritional Physiology, Anglia Ruskin University
One molecule in particular, NAD+ , has attracted growing interest, with claims it can boost energy, improve vitality, slow ageing and even help us live longer.
But does the science support these claims? And can NAD+ supplements really help us age more healthily?
NAD+ (short for nicotinamide adenine dinucleotide) is found in every cell in our bodies. It plays an essential role in helping our cells turn food into energy . Without it, many of the processes that keep us alive would be unable to function.
NAD+ also supports numerous enzymes and proteins, including sirtuins, which help regulate inflammation, DNA repair and the function of mitochondria , the structures responsible for producing much of the energy our cells need.
Research suggests that NAD+ levels decline as we get older . This is partly because damage to our DNA accumulates over time, activating enzymes that use up NAD+ more quickly. Another enzyme, called CD38, also becomes more active with age and inflammation, increasing NAD+ use. Meanwhile, our cells may become less efficient at producing it .
The extent of this decline varies between people and different tissues, with some studies suggesting that NAD+ levels may fall by between 10% and 80% as we age.
Lower NAD+ levels have been linked to reduced energy production in cells, slower DNA repair and other changes associated with ageing.
Animal studies suggest that increasing NAD+ levels may improve muscle function and metabolism and even cognitive function , encouraging researchers to investigate whether similar benefits are possible in humans.
Can supplements boost our NAD+ levels?
There is limited evidence that taking NAD+ itself as a supplement effectively increases NAD+ levels, as it is broken down during digestion . A potential solution to this could be liposomal NAD+, where the molecule is enclosed in tiny fat-based structures designed to improve absorption.
A 2026 study involving 14 people found that taking 1,000mg of liposomal NAD+ daily for two weeks increased NAD+ levels inside cells by more than 64%. However, larger, carefully controlled studies are needed to confirm this finding.
Most human research has instead focused on NAD+ precursors: substances the body uses to make NAD+. These include two compounds derived from vitamin B3, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN).
There is good evidence that both can increase NAD+ levels in the blood.
In one randomised, placebo-controlled study involving 140 overweight but otherwise healthy adults aged 40-60, NR supplementation increased blood NAD+ levels over eight weeks. The greatest increase occurred among those taking 1,000 mg (milligrams) daily, whose levels rose by 142% after two weeks and remained elevated throughout the study.
Another study involving 30 healthy adults found that taking 250 mg of NMN daily increased blood NAD+ levels by around 50% after four weeks, with levels remaining elevated throughout the 12-week trial.
High doses of vitamin B3 may also increase NAD+ , although these can be poorly tolerated over longer periods.
Together, these findings suggest that NAD+ precursors can successfully raise blood NAD+ levels. However, whether this also increases levels in other tissues, such as muscles and organs, remains unclear .
Can increasing NAD+ levels help us age more healthily?
Animal studies have produced encouraging results, with NAD+ precursors improving physical performance, insulin sensitivity and the way cells produce energy . One study found that giving older mice NR for six weeks increased their lifespan by an average of 39 days , equivalent to around 5%.
However, results from human studies have been less convincing.
A recent systematic review examined 33 human studies and found inconsistent effects on physical function, metabolism and other measures of healthy ageing.
For example, one study involving men aged over 65 found that taking 250 mg of NMN daily for 12 weeks improved walking speed by around 7% and left-hand grip strength by approximately 4%. Both are useful measures of physical function as we age. However, only 20 of the 42 participants completed the full study as planned, so larger trials are needed to confirm these findings.
In contrast, a 24-week study involving 14 older men with diabetes and reduced physical function found no significant improvements in walking speed or grip strength after taking the same dose of NMN.
These differences highlight how difficult it is to draw firm conclusions from small studies involving people with different health conditions.
There have been some other promising findings. A study involving recreational runners found that taking 600 mg or 1,200 mg of NMN daily alongside exercise training for six weeks improved some measures of the body's ability to use oxygen during exercise.
This raises the possibility that NAD+ precursors could improve certain aspects of exercise performance. However, further research is needed to establish whether these effects lead to longer-term improvements in fitness or healthier ageing.
NAD+ supplements: should you take them?
The growing research into NAD+ supplements is certainly intriguing. There is good evidence that precursors such as NR and NMN can increase blood NAD+ levels.
However, we still lack convincing evidence that these supplements can help us stay healthier for longer, reduce age-related decline or extend our lives.
Larger, longer clinical trials are needed to establish whether these supplements can lead to meaningful health benefits influencing our healthspan or lifespan.
For now, if you want to age healthily, the strongest evidence continues to support eating a varied, nourishing diet, managing stress and taking regular physical activity that helps maintain strength, fitness and mobility as you get older.
Professor Roberts has previously received external research funding unrelated to this article.
