NAD+ levels decline with age, dropping roughly 50% between your 40s and 60s in some tissues. The good news: you can push those levels back up through a combination of targeted supplements, exercise, dietary strategies, and certain plant compounds. Each approach works through a different mechanism, so stacking several together tends to produce the best results.
Why NAD+ Levels Matter
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every cell. It drives energy production, DNA repair, and the activity of sirtuins, a family of proteins linked to metabolic health and longevity. When NAD+ drops, cells struggle to produce energy efficiently, repair damage slows down, and inflammation tends to increase. Your body replenishes NAD+ through three pathways, but the salvage pathway handles about 85% of total production. That pathway depends on a rate-limiting enzyme called NAMPT, which recycles used NAD+ back into a usable form. Most strategies for raising NAD+ either feed raw materials into these pathways or protect existing NAD+ from being broken down too quickly.
NAD+ Precursor Supplements
The most direct way to raise NAD+ is to give your body more of the building blocks it needs. Three forms of vitamin B3 serve as NAD+ precursors, but they differ significantly in efficiency and side effects.
Nicotinamide Riboside (NR)
NR is currently the most studied precursor supplement. It converts to NAD+ more efficiently than older forms of B3, and it has been evaluated in 13 published human trials with no severe attributable side effects. In a randomized controlled trial published in The Lancet, participants taking 2,000 mg of NR per day showed measurable increases in blood NAD+ within five weeks. That particular trial focused on long-COVID patients and found that while NR reliably boosted NAD+, it didn’t significantly improve fatigue, sleep, or cognition compared to placebo in that population. The NAD+ increase itself, though, was consistent and well-documented.
NMN (Nicotinamide Mononucleotide)
NMN sits one step closer to NAD+ in the salvage pathway, which is why it attracted intense interest. Its regulatory history has been rocky: the FDA pulled its dietary supplement status in late 2022 because it was simultaneously being investigated as a drug candidate. As of 2025, the FDA reversed that decision and confirmed NMN is lawful for sale as a dietary supplement in the U.S. Brands still can’t make medical claims, but the product is legally available again. Human data on NMN is growing, though it currently has fewer published clinical trials than NR.
Niacin (Nicotinic Acid) and Nicotinamide
Plain niacin is the oldest and cheapest B3 option, but it causes intense skin flushing: redness, itching, and warmth that many people find intolerable. It also carries a risk of liver toxicity at high doses. Nicotinamide (also called niacinamide) avoids the flushing problem because of a slight structural difference, but it raises NAD+ less efficiently than NR and can inhibit sirtuins at very high doses. Both are available over the counter and inexpensive, making them reasonable starting points if cost is a concern, but NR and NMN offer a more targeted approach.
Exercise Boosts Your Body’s Own Production
Exercise increases NAD+ not by supplying precursors from outside, but by upregulating the NAMPT enzyme that drives the salvage pathway from within. A systematic review with meta-analysis found that exercise training reliably raises NAMPT levels in skeletal muscle, with aerobic exercise showing a 75.1% probability of increasing the enzyme and resistance exercise showing a 66.4% probability. Both work, but cardio appears to have a slight edge.
Age and sex matter somewhat. Young adults had a 75.6% probability of NAMPT increase from training, while older adults still saw a meaningful 68.7% probability. Men showed the strongest response at 79.3%. These aren’t dramatic differences, and the takeaway is straightforward: regular exercise of any type supports NAD+ production regardless of your age or sex. The effect compounds over time because trained muscles maintain higher baseline NAMPT activity.
Caloric Restriction and Fasting
The connection between eating less and living longer has been studied for decades, and NAD+ turns out to be a key part of that link. Caloric restriction activates the NAD+ salvage pathway and stimulates sirtuins, the same protective proteins that NAD+ fuels. The earliest evidence came from yeast studies where mimicking caloric restriction through the salvage pathway increased both stress resistance and lifespan. In humans, intermittent fasting and time-restricted eating are the most practical ways to tap into this mechanism without chronic calorie counting.
You don’t need extreme fasting protocols. A consistent overnight fast of 14 to 16 hours gives your body a window of lower energy intake that nudges the NAD+ salvage pathway upward. The effect is modest compared to supplementation, but it stacks well with other approaches and carries additional metabolic benefits on its own.
Plant Compounds That Protect Existing NAD+
Raising NAD+ production is only half the equation. Your body also has enzymes that consume NAD+, and one of the most significant is CD38, whose activity increases with age. This is one reason NAD+ declines as you get older: you’re burning through it faster. Certain flavonoids found in fruits and vegetables can inhibit CD38, slowing NAD+ degradation and allowing levels to recover.
Quercetin, found in onions, apples, and capers, inhibits both CD38 and another NAD+-consuming enzyme called PARP-1. It doesn’t exhibit toxicity after oral consumption and has been studied extensively as a safe, mild inhibitor. Apigenin, abundant in parsley, celery, and chamomile tea, works through the same mechanism. Other flavonoids with similar effects include kaempferol (found in kale and spinach), fisetin (strawberries), and catechins (green tea). None of these compounds produce dramatic NAD+ spikes on their own, but they help preserve what your body makes, especially when combined with precursor supplements or exercise.
Combining Strategies for the Biggest Effect
Each approach targets a different bottleneck. Precursor supplements provide raw materials. Exercise cranks up the NAMPT enzyme that converts those materials. Fasting creates the metabolic conditions that favor NAD+ production. Flavonoids slow down the enzymes that destroy NAD+ once it’s made. Using all four together addresses the problem from every angle, and most longevity-focused practitioners recommend exactly this kind of layered approach.
A practical starting stack might look like: an NR or NMN supplement taken daily, regular aerobic exercise three to five times per week, an overnight fasting window of at least 14 hours, and a diet rich in quercetin and apigenin from whole foods or targeted supplements. You don’t need to do everything at once. Adding one habit at a time lets you notice how each change affects your energy and wellbeing.
Side Effects and Safety Considerations
At standard supplement doses, most people tolerate NAD+ precursors well. The most common side effects are mild: nausea, stomach discomfort, headaches, lightheadedness, diarrhea, and occasional muscle cramps. These tend to appear at higher doses and in concentrated capsule form rather than from dietary sources. Plain niacin carries the additional risk of flushing and liver toxicity at high doses, which is why most people prefer NR or NMN.
The most significant safety concern involves cancer. NAD+ supports energy production in all cells, including cancerous ones. There’s theoretical concern that boosting NAD+ could fuel tumor growth in people with active cancer or a strong cancer history. This hasn’t been proven, but it hasn’t been ruled out either, and long-term safety data for most NAD+ supplements simply doesn’t exist yet. If you have a history of cancer, advanced liver disease, or are pregnant or breastfeeding, talk to your doctor before starting supplementation.