Understanding the interactions, benefits, and safety of combining these two powerful supplements.
We found no documented interaction between Vitamin D3 with A, E and K2 and NR in the sources below. That isn't proof the combination is right for you: check each one's cautions, and ask your pharmacist if you take medication.
What it is: A combination of vitamin D3 with vitamins A, E and K2. Vitamin D helps the body absorb calcium and supports muscles, nerves and the immune system.
What the research says: Getting enough vitamin D and calcium helps protect against osteoporosis.
In Holitro: D Complex (5,000 IU per capsule)
Sources: NIH Office of Dietary Supplements: Vitamin D: Fact Sheet for Consumers (updated November 2022); NIH Office of Dietary Supplements: Vitamin A: Fact Sheet for Consumers (updated March 2025); NIH Office of Dietary Supplements: Vitamin E: Fact Sheet for Consumers (updated March 2021); NIH Office of Dietary Supplements: Vitamin K: Fact Sheet for Consumers (updated March 2021)
What it is: A form of vitamin B3 that the body uses to make NAD+, a molecule involved in energy production.
What the research says: It reliably raises NAD+ levels and was well tolerated for weeks to months in trials, but effects on health and aging have been mixed or absent.
In Holitro: NR (500 mg per capsule)
Source: PubMed review: NAD+ supplementation for anti-aging: systematic review (2026) (updated February 2026)
Check with your doctor or pharmacist, especially if you take medication.
Check your stack — freeEducational information only, not medical advice. This reflects general ingredient overlap, not a personalized safety review. Always check with your doctor or pharmacist before combining supplements, especially if you take medication, are pregnant or nursing, or manage a health condition. These statements have not been evaluated by the FDA.
Balancing dosages across multiple different bottles is risky, inefficient, and expensive. D Complex is already lab-dosed and delivered daily in our Immune Pack — one less bottle to manage.
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