Nicotinamide adenine dinucleotide (NAD+) is a vital molecule found in every cell of the body. It plays a central role in energy metabolism, cellular repair, immune function, and overall longevity. However, NAD+ levels decline with age—and this decline has been linked to numerous health conditions, including heart disease, diabetes, neurodegenerative disorders, and muscular diseases.

As a result, NAD+ supplements have gained popularity for their potential to boost energy, support metabolic health, and even improve brain function. But before adding NAD+ boosters to your supplement routine, it’s important to understand that they may interact with certain medications and other supplements.

1. Diabetes Medications (Including Insulin and Metformin)

If you manage your blood sugar with insulin or medications like metformin, NAD+ supplements may interfere with how your body responds.

  • Some studies suggest that high doses of nicotinamide (NAM)—a precursor to NAD+—can decrease insulin sensitivity, potentially leading to insulin resistance.

  • This interaction could diminish the effectiveness of diabetes medications, increase blood glucose levels, and complicate blood sugar control.

Caution: Always consult with your doctor if you have diabetes and are considering NAD+ supplementation.

2. Blood Pressure Medications

NAD+ has been shown in some studies to lower blood pressure, especially at higher doses (more than 2 grams per day).

  • If you’re taking antihypertensive drugs, combining them with NAD+ could lower your blood pressure too much, increasing your risk of dizziness, fatigue, or fainting.

  • People with low baseline blood pressure should be especially cautious.

Recommendation: Monitor blood pressure regularly and speak with your provider before combining these therapies.

3. Cancer Treatments

Although NAD+ supports cellular energy, it can potentially be harmful for individuals undergoing cancer treatment.

  • Research suggests that cancer cells may use NAD+ to fuel growth and resist treatment, making NAD+ boosters counterproductive during chemotherapy.

  • Some cancer therapies work by reducing NAD+ in tumor cells—so taking supplements may interfere with the treatment’s mechanism.

Advice: Avoid NAD+ supplements during cancer therapy unless directed by your oncologist.

4. Anticoagulants (Blood Thinners)

Certain NAD+ precursors, such as niacin, may interact with blood thinners like warfarin (Coumadin).

  • These supplements could affect the way your body metabolizes anticoagulants, increasing your risk of either clotting or excessive bleeding.

  • If taken together, your healthcare provider may need to adjust your INR (International Normalized Ratio) monitoring schedule.

Tip: If using both, ensure there’s medical supervision and timing separation between doses.

5. Antioxidant Supplements (e.g., Resveratrol and Quercetin)

Some antioxidants can naturally boost NAD+ levels, but combining them with NAD+ supplements may amplify side effects such as:

  • Headaches

  • Nausea

  • Skin flushing or irritation

  • Fatigue and abdominal discomfort

For instance, resveratrol may increase NAD+ levels up to five times, which can intensify reactions when used with NAD+ supplements.

Tip: If combining both, start with lower doses and monitor your body’s response.

6. Antidepressants

The connection between NAD+ and mood disorders is still being explored. While low NAD+ levels have been linked to depression and anxiety, combining antidepressants with NAD+ boosters can be tricky.

  • Some antidepressants interact with the same enzymes that regulate NAD+ production.

  • This could affect how much NAD+ is synthesized or utilized in the brain.

Caution: There isn’t enough human research yet, so talk to your psychiatrist before mixing NAD+ with mood-regulating medications.

7. Melatonin

Both NAD+ and melatonin influence your circadian rhythm—the internal clock that regulates your sleep-wake cycle.

  • Taking both at night may lead to excessive drowsiness, fogginess, or trouble staying alert during the day.

  • This combination might disturb sleep patterns rather than improve them.

Tip: Space out your intake or adjust timing based on how your body responds.

When to Consult a Healthcare Provider

Because long-term human studies on NAD+ supplementation are limited, it’s important to be cautious—especially if you have underlying health conditions or take daily medications.

You should avoid NAD+ supplements if:

  • You are pregnant or breastfeeding

  • You have celiac disease or are immunocompromised

  • You’re being treated for cancer or heart disease without guidance

Speak to your healthcare provider if you're on medications for:

  • High blood pressure

  • Diabetes

  • Mood disorders

  • Blood clotting or cardiovascular conditions

They can help assess whether NAD+ is safe for your specific situation.

Quick Recap

NAD+ supplements may offer promising benefits—from boosting energy to slowing signs of aging. But they’re not risk-free. NAD+ can interact with medications for blood sugar, blood pressure, cancer, and more.

Bottom line: Never start a new supplement without checking for interactions—especially if you’re managing chronic conditions. Personalized advice from your doctor is essential.