NAD+ and precursors side effects and risks

Reported side effects

• Stomach upset with oral NR: In an 8 week trial: 20.0%, 14.3%, 11.4% at 100, 300, 1000 mg/day vs 14.3% placebo., mild. Review persistent symptoms and other supplements; rates vary widely across populations. (source)
• Diarrhea with NR or an NR combination: PAD trial: NR 39.3%; NR plus resveratrol 54.6%; placebo 27.6%., moderate. Assess ongoing diarrhea and hydration. The combination may be less tolerable. (source)
• NAD+ infusion cramps, nausea and chest pressure: All 6 NAD+ clients in a small retrospective series reported symptoms; this is not a general incidence estimate., moderate. Pause the infusion and alert clinical staff. Chest pain, breathlessness or fainting needs urgent assessment. (source)
• Severe chills, shaking, vomiting or fatigue after injections: unknown, serious. Get urgent assessment; FDA reports were consistent with excessive endotoxin contamination. (source)
• Injection pain and local irritation: NR shot preprint: pain >2 minutes 45.9%; soreness/tightness 43.2%. NAD+ route specific rates were not published there., moderate. Persistent redness, warmth, swelling or fever needs assessment. (source)
• Headache or nausea with high-dose NR: NR 3000 mg/day: 3 headache events and 2 nausea events vs 0 and 0 placebo, in 10 people per arm., mild. These are small-study event counts, not a reliable population frequency. (source)
• Poor sleep, jitteriness or anxiety: unknown, moderate. Reported online with NR/NMN or NAD+ shots; causal links and rates are unproven. (source)
• Iontophoresis patch skin irritation: 25% in the uncontrolled NAD+ plus naltrexone study., mild. Stop applying to irritated skin and have the reaction assessed. (source)

Stop and get help if

• Severe chills, shaking, repeated vomiting or sudden illness after an injection: Stop administration and get urgent medical assessment; contamination or endotoxin is possible.
• Chest pain, breathlessness, fainting or a sustained racing heart during an infusion: Stop the infusion and seek urgent assessment; do not assume it is a normal NAD+ sensation.
• Spreading redness, marked warmth, swelling or fever after an injection: Get prompt medical assessment for infection or a serious reaction.
• Face or tongue swelling, wheezing or trouble breathing after administration: Stop administration and seek emergency care for a possible severe reaction.
• Sudden severe vomiting, diarrhea, agitation or confusion after starting naltrexone in the NAD+ combination: Seek urgent medical care for possible opioid withdrawal triggered by naltrexone.

Who should avoid it

• pregnant: This is an editorial screen, not an FDA NAD+ label.
• breastfeeding: This is an editorial screen, not an FDA NAD+ label.
• tryingToConceive: This is an editorial screen, not an FDA NAD+ label.
• under18: Some rare-disease studies enrolled children; they do not establish routine wellness use under 18.
• activeCancer: Animal NR data show a tumor-growth/spread signal. Human risk is unknown; review any NAD booster with the oncology team.
• cancerHistory: Cancer recurrence risk has not been tested adequately; animal findings cannot quantify human risk.
• kidneyDisease: Small kidney-disease trials do not establish safe self-dosing, particularly during acute illness.
• liverDisease: Liver safety needs individual review. A negative liver-fat trial of an NR combination is not proof of liver treatment.
• heartCondition: NAD+ infusions can cause chest pressure and faster heart rate. Heart-failure trials used monitored care.
• diabetes: NMN may change insulin responses. Review glucose monitoring and medicines; a hypoglycemia interaction is not established.
• testedAthlete: IV fluid volume can breach WADA M2.2 even when the infused substance is not prohibited.
• other: The large NR Parkinson trial found worse clinical scores than placebo; discuss supplementation with the treating neurologist.
• other: Do not repeat exposure after a serious reaction until the ingredient, excipients and possible contamination are assessed.
• other: For the naltrexone combination only: opioid analgesics, current opioid dependence or acute withdrawal contraindicate naltrexone. It can trigger severe withdrawal.

Interactions

• Other NAD+ boosters or high-dose vitamin B3: Duplicate exposure has no proven extra benefit. NR, NMN, NAD+ and niacin are not interchangeable milligram for milligram.
• Insulin and sulfonylureas: A direct interaction is unproven. Because NMN changed insulin sensitivity in one trial, discuss extra glucose checks when medicines lower blood sugar.
• Levodopa and Parkinson medicines: NR-SAFE had changes in movement symptoms and levodopa use. NOPARK found worse scores; a direct drug interaction remains unproven.
• Cancer treatment and NAD-pathway drugs: NAD supports DNA-repair pathways used in cancer biology. Clinical interaction effects are unknown; review with the oncology team.
• Opioids, only when naltrexone is included: NAD+–naltrexone combination only: opioid use or dependence contraindicates naltrexone and can cause severe withdrawal. Assess recent use before starting.

Product quality risks

• FDA reports of severe reactions to NAD+ injections were consistent with endotoxin contamination.
• A study tested 18 NMN products. NMN deviations from adjusted label claims ranged from −100% to +11.2%.
• An oral purity result cannot establish injectable sterility, endotoxin safety or correct dose.
• A 2026 FDA warning identified NAD+ bulk compounding outside 503B eligibility and major sterile-manufacturing failures.