Which supplements or medications are best not combined with NAD+?
The combination of NAD+ supplements, particularly nicotinamide, with platinum-based chemotherapy is the most concrete reason for caution. For other interactions the indications are preliminary, but worth discussing if you use multiple substances.
The most concrete warning concerns nicotinamide in combination with platinum-based chemotherapy (cisplatin). Laboratory research shows that nicotinamide can form a compound with reactive platinum species, leaving less active cisplatin available to kill cancer cells. This has been demonstrated in cell studies, not in humans, but the mechanism is specific enough to take seriously. Never take nicotinamide, NMN or NR on your own initiative if you are receiving platinum-based chemotherapy; discuss this with your doctor.
A second risk lies in high doses of nicotinamide itself. Nicotinamide is a building block of NAD+, but at high doses it simultaneously inhibits the enzyme SIRT1, which itself requires NAD+ to function. That enzyme helps control oxidative stress. At excessively high doses, that protective effect may be lost, increasing free radical activity and inflammation. This has been observed in cell studies, not in clinical research involving humans.
Experimental cancer drugs that block NAD+ production, known as NAMPT inhibitors, cause dangerous platelet deficiencies. Niacin, another vitamin B3 form, can partially compensate for that damage via an alternative pathway. This illustrates that the NAD+ pathway is sensitive to disruption by drugs and that B3 variants can interfere with one another.
Popular supplements such as quercetin, genistein, Ginkgo Biloba, soy isoflavones and milk thistle contain plant compounds that inhibit or activate liver enzymes. Those enzymes also break down many medications. Anyone combining NAD+ supplements with other substances that travel through the same liver pathways risks having the effect of those medications strengthened or weakened. This is a broad interaction risk, not specific to NAD+, but relevant if you use multiple supplements or medications at the same time.
Sulforaphane, an extract from broccoli sprouts, and fucoidan, a seaweed supplement, disrupt similar liver pathways. Sulforaphane clashed in cell studies with the diuretic furosemide, the cardiac drug verapamil and the painkiller ketoprofen. Fucoidan inhibited liver enzymes in laboratory research. The evidence for this is limited and does not come from studies in humans, but even 'natural' supplements can interfere with medications in unexpected ways. If you use medications, always discuss combinations with your doctor or pharmacist.
All claims are based on cell and/or animal studies (PMID 42278515, 28000862, 25894564, 16289744, 23238480, 29096568). No large human RCTs or meta-analyses are available on these specific combinations. The level of evidence is therefore limited to preliminary mechanistic and toxicological indications.
Which supplements are best avoided when taking blood thinners?
Ginkgo biloba, ginger, garlic, cranberry and St John's wort are best known as risky combinations with warfarin and similar blood thinners. Tell your doctor or pharmacist which supplements you use, because even seemingly harmless products can affect the balance of blood clotting.
Are NAD+ supplements (NMN/NR) worth it?
NMN and NR demonstrably raise NAD+ in your blood and appear to be safe, but whether you will notice any benefit in muscle strength, heart function or memory has not yet been proven in humans. Note also: NR is authorised in the EU as a supplement; NMN is not (yet).
What does a NAD supplement do, and does it work in people?
NAD supplements demonstrably raise NAD levels in your blood, but whether you actually benefit from that remains uncertain. If you want to try them, keep your expectations realistic and choose a dose with the best available evidence behind it.
What is best not to combine with creatine?
Combining creatine with caffeine powder adds nothing to your performance and increases the risk of gastrointestinal complaints; ready-made pre-workout blends with many ingredients carry additional risks due to possible contamination and unknown long-term effects.
What is NAD+ and what does it do in your body?
NAD+ is an indispensable molecule for energy, DNA repair and cell maintenance, and its levels measurably decline with age. Whether that decline can be corrected with supplements, and what benefit that would bring, is a separate question.
Which foods or habits effectively raise NAD+ levels?
Exercise and NAD+ supplements (NR or NMN) demonstrably raise NAD+ levels, but whether higher levels also confer health benefits in humans has not yet been proven. Regular physical activity is the only approach for which broader health benefits have also been demonstrated.