Question 247 of 433
What is NAD, and do NMN and NR work?
The short answer
NAD is a molecule every cell uses to make energy and repair DNA, and it declines with age. NMN and NR reliably raise NAD in blood. Whether that makes people healthier is still unproven.
Dr. David Sinclair’s Lifespan made these supplements famous. The human trials since then have been underwhelming: small improvements in a few measures in a few studies, such as insulin sensitivity in muscle or walking distance in people with artery disease, and no effect in many others. NR did not extend life in the federal mouse program.
A regulatory note: after a long dispute, the FDA confirmed in September 2025 that NMN can lawfully be sold as a supplement. Legal is not the same as proven. NAD infusions and injections are expensive, often cause nausea and flushing, and have no good evidence behind them.
“This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship.” From the book’s medical disclaimer. Full disclaimer
HUMAN BIOMARKER STUDIES — NAD precursors raise blood NAD; meaningful clinical outcomes and general longevity benefit remain unproven.Evidence grade (draft mapping)Grade pendingPart 17, Q247 · Part sources
From Longevity Unmasked by Afshine Ash Emrani, MD, FACC. Medical disclaimer. This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship. Nothing here is meant to diagnose, treat, cure, or prevent any disease. Medicine is personal: a test, drug, supplement, or exercise plan that helps one person can harm another. Do not start, stop, or change any medication or treatment because of something you read in these pages. Talk with a licensed clinician who knows your history first. If you think you are having a medical emergency, call 911. The author disclaims responsibility for any loss or harm arising from use of the information in this book.