Hi Diana, Thank you for trying Qualia NAD+, and for your feedback! Increased heart rate or flushing can occur in Qualia NAD+ due to Qualia increasing circulatory function, but typically will subside in 15 minutes or so after taking. The nicotinic acid (niacin) form of vitamin B3 can cause flushing when taken in amounts substantially more than the daily value (DV) amount. Qualia NAD+ contains nicotinic acid, but in an amount below the level where flushing has occurred in studies. The other common form of vitamin B3, niacinamide, does not cause flushing. NIAGEN® Nicotinamide Riboside, a next generation vitamin B3, also does not cause flushing.* If you continue to take Qualia NAD+ and the flushing continues and/or is uncomfortable, please let us know and we'll be happy to assist you in a return of the product under our product guarantee. Qualia NAD+ is designed to work beneath the surface (it's a cellular health supplement), so its primary purpose is not to deliver results you'd feel. That said, “energy”  (i..e, having more energy, feeling more energetic. etc.) is the theme we most commonly get as anecdotal feedback. A more balanced mood (i.e., less moody or irritable, more calm. etc.), sleep (i..e, needing a bit less, feeling better rested, etc.) and general well-being are other areas that can be experienced. But keep in mind that everyone is unique and results vary from person to person.* If we can support further, please let us know.  With kindness, Bailey *These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.