How to increase NAD+: studied approaches and their limitations

How can you increase NAD+? The question arises when discussing ageing, because this coenzyme essential for energy production declines with age in several tissues. Exercise, fasting, sleep, alcohol, diet and supplements: many approaches are proposed, but not all have been measured in humans. This guide separates human observations from animal findings and examines NAD+ tests.

Can NAD+ really be increased?

Yes, but not in the same way for every approach. Precursors taken as supplements increase the NAD+ measured in the blood: this is demonstrated. Lifestyle approaches mainly act on the enzymes that produce and consume NAD+ in tissues, particularly muscle, and their effects are harder to measure.

For this molecule's role, see what NAD+ is and why it declines with age. The table summarises studied approaches.

Physical activity: the best-documented approach

In muscle, NAD+ is mainly produced through the salvage pathway, whose rate-limiting enzyme is called NAMPT. In a study of 57 adults, the amount of NAMPT in muscle was lower in older participants. It depended mainly on their maximum aerobic capacity.

Endurance or strength training?

Both increased NAMPT. After twelve weeks of endurance training, muscle NAMPT rose 12% in young people and 28% in those aged 55 or over. Strength training produced 25% and 30% increases. In older participants, training eliminated the age-related difference.

Another study followed 16 sedentary, overweight adults, with a mean age of 59, through 10 weeks of strength training with two sessions per week. Their muscle NAD+ increased by 127%, and NAMPT by 15%. Before training, their muscle NAD+ was lower than that of trained young men; afterwards, it was comparable.

What these studies do not establish

• The first measured NAMPT, not NAD+ itself.
• The second involved sixteen people without a control group.
• Blood results differ by method, discussed below.

These limitations do not reduce physical activity's value for many other reasons. They simply encourage caution about numerical promises.

Fasting and calorie restriction: mainly animal evidence

Fasting and calorie restriction are often presented as ways to increase NAD+. The evidence comes mainly from mice. During fasting and after exercise, their muscle activates an energy sensor, AMPK, which triggers metabolic adaptation through the sirtuin SIRT1. This sensor works precisely by increasing NAD+ in cells.

Direct human tissue measurements after fasting are rare, and we found no controlled trial showing intermittent fasting raises NAD+. If fasting for other reasons, seek medical advice with medication, diabetes or pregnancy.

Sleep and circadian rhythm

NAD+ follows a 24-hour rhythm. In mice, the biological clock controls NAMPT production and daily NAD+ oscillation. NAD+ in turn affects the clock through SIRT1: the systems form a loop.

In humans, it is not yet known whether better sleep or regular times alter tissue NAD+. Sufficient, regular sleep remains foundational to health; our sleep and melatonin article details studied approaches.

Alcohol: a major NAD+ consumer

Alcohol is one of the few influences whose effect on NAD+ is well understood. In the liver, the two enzymes that break it down, alcohol dehydrogenase followed by aldehyde dehydrogenase, each convert NAD+ to NADH. The ratio between the two forms falls, both in the cytoplasm and in the mitochondria.

This imbalance slows pathways needing NAD+: fat breakdown, Krebs cycle and liver glucose production. Excess alcohol also risks insufficient B3 intake. For the NAD+/NADH pair, see our dedicated article.

Diet: vitamin B3 and tryptophan

NAD+ is made from two dietary raw materials: vitamin B3 (niacin) and tryptophan, an amino acid found in proteins. The main sources of B3 are liver, meat, fish, seafood and whole grains. In some cereals, niacin is bound to other molecules and only around 30% is absorbed.

Around 60mg of tryptophan is needed to obtain the equivalent of 1mg of niacin. This conversion decreases if vitamin B2, vitamin B6 or iron intake is insufficient. In France, ANSES recommends 1.6mg of niacin equivalent per megajoule of energy consumed, or 16mg per day for 10 MJ (around 2,400 kcal).

Two authorised claims govern its role: “niacin contributes to normal energy-yielding metabolism” and “niacin contributes to the reduction of tiredness and fatigue”. B3 and tryptophan each have dedicated articles.

Supplemental precursors: overview

Precursors are forms of vitamin B3, or related molecules, that cells convert into NAD+. Their effect on blood NAD+ is the most firmly established of the approaches studied in humans.

NR is best documented. EFSA judged it safe up to 300mg daily in healthy adults and 230mg during pregnancy and breastfeeding. It also confirmed release of nicotinamide, a B3 form. 300mg is the dose in Hexagon® NAD+ Nicotinamide Riboside Chloride 300mg, one capsule daily.

NMN uses the same salvage pathway and also increases blood NAD+. The choice between NMN and NR is discussed in a dedicated article, as are the results of NR clinical trials. Nicotinic acid is a classic precursor, but it causes flushing, and ANSES sets its safety limit at 10mg per day. For nicotinamide, the limit is 900mg per day; nausea and liver toxicity have been reported at around 3 g per day.

Can NAD+ be measured? What tests are worth

Yes, in blood. Finger-prick drop tests exist alongside laboratory analysis. But they measure whole-blood NAD+, not muscle or brain tissue NAD+.

Their results are contradictory. Using a finger-prick test, one team observed an increase in blood NAD+ after endurance exercise or NMN, and a stable baseline level over 100 days in the same person. In contrast, a 2026 analysis using a rigorously validated laboratory method found blood NAD+ stable with age and during lifestyle interventions. Only nicotinamide riboside increased it.

A test can therefore verify a precursor raises blood NAD+. It cannot assess “biological age” or reveal tissue changes. The 2026 authors question blood NAD+'s value as an ageing marker or lifestyle marker.

Frequently asked questions

Does coffee increase NAD+?

Coffee contains trigonelline, a molecule that cells can convert into NAD+. It increases NAD+ in worms, in mice and in cultured human muscle cells. In humans, only correlations are available: blood trigonelline levels are lower in people with sarcopenia. Much of the study was conducted by the research centre of a food industry group.

Are NAD+ infusions useful?

They have been studied very little. In a pilot study, 750mg of NAD+ infused over six hours into eight healthy men disappeared from plasma during the first two hours, probably broken down by enzymes in the blood. The study did not measure any health effects, and an infusion remains a medical procedure.

Is swallowing NAD+ capsules useful?

Food NAD+ is converted to nicotinamide before intestinal absorption. Capsules therefore probably mainly supply B3 rather than ready-to-use NAD+. This explains research focus on precursors such as NR.

Why does exercise increase muscle NAD+?

Training increases the density of mitochondria in muscle. In the strength-training trial, the increase in NAD+ went hand in hand with an increase in citrate synthase activity, a marker of this density, which rose by 183%. However, a cause-and-effect relationship remains to be established.

Can diet alone increase NAD+?

It supplies raw material and prevents deficiency, the essential point. Meat or fish supplies 5 to 10mg niacin per serving; a 300mg NR capsule releases around 126mg nicotinamide, far beyond need. Health value of this surplus without deficiency is unproved.

Do men and women have equal NAD+?

Not quite. In the finger-prick study, men's mean blood NAD+ exceeded women's before fifty. Any health consequence is unknown.

Conclusion

To increase NAD+, the best-supported human approach is physical activity, endurance and strength, stimulating muscle NAMPT and NAD+. Limiting alcohol and meeting B3 and tryptophan requirements preserve raw materials and NAD+/NADH balance. Fasting and circadian rhythm remain mainly animal possibilities. Precursors raise blood NAD+, but health benefits remain unproved and blood tests do not reveal tissue levels.

Sources

1. de Guia RM et al. (2019). Aerobic and resistance exercise training reverses age-dependent decline in NAD+ salvage capacity in human skeletal muscle. Physiological Reports, 7(12), e14139. doi:10.14814/phy2.14139
2. Lamb DA et al. (2020). Resistance training increases muscle NAD+ and NADH concentrations as well as NAMPT protein levels and global sirtuin activity in middle-aged, overweight, untrained individuals. Aging (Albany NY), 12(10), 9447-9460. doi:10.18632/aging.103218
3. Cantó C et al. (2009). AMPK regulates energy expenditure by modulating NAD+ metabolism and SIRT1 activity. Nature, 458(7241), 1056-1060. doi:10.1038/nature07813
4. Cantó C et al. (2010). Interdependence of AMPK and SIRT1 for metabolic adaptation to fasting and exercise in skeletal muscle. Cell Metabolism, 11(3), 213-219. doi:10.1016/j.cmet.2010.02.006
5. Ramsey KM et al. (2009). Circadian clock feedback cycle through NAMPT-mediated NAD+ biosynthesis. Science, 324(5927), 651-654. doi:10.1126/science.1171641
6. Cederbaum AI (2012). Alcohol metabolism. Clinics in Liver Disease, 16(4), 667-685. doi:10.1016/j.cld.2012.08.002
7. NIH Office of Dietary Supplements (2022). Niacin – Fact Sheet for Health Professionals. ods.od.nih.gov
8. ANSES. Nutritional references for vitamins and minerals. anses.fr
9. Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. eur-lex.europa.eu
10. Membrez M et al. (2024). Trigonelline is an NAD+ precursor that improves muscle function during ageing and is reduced in human sarcopenia. Nature Metabolism, 6(3), 433-447. doi:10.1038/s42255-024-00997-x
11. EFSA NDA Panel (2019). Safety of nicotinamide riboside chloride as a novel food pursuant to Regulation (EU) 2015/2283 and bioavailability of nicotinamide from this source, in the context of Directive 2002/46/EC. EFSA Journal, 17(8), e05775. doi:10.2903/j.efsa.2019.5775
12. Grant R et al. (2019). A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+. Frontiers in Aging Neuroscience, 11, 257. doi:10.3389/fnagi.2019.00257
13. Wang P et al. (2023). Fingerstick blood assay maps real-world NAD+ disparity across gender and age. Aging Cell, 22(10), e13965. doi:10.1111/acel.13965
14. Tretowicz MM et al. (2026). Human whole-blood NAD+ levels do not vary with age or lifestyle interventions. Nature Metabolism, 8(6), 1282-1290. doi:10.1038/s42255-026-01537-5

Food supplements do not replace a varied, balanced diet or a healthy lifestyle. Ask a healthcare professional for advice if you are taking medication, pregnant or breastfeeding.