The Truth About NAD: Why More NAD Might Be Making You Worse

About this video

Yurth warns against repeatedly adding NAD or its precursors without understanding why levels fall. Using a leaking-bucket analogy, she argues that age, stress and illness raise NAD-degrading enzymes, which she names as CD38 and NNMT, so replenishment alone does not fix the underlying drain. She further claims that excess breakdown products could harm methylation and could preferentially support senescent or malignant cells, a contested interpretation she attributes to emerging research and expert discussion. Her preferred direction is addressing the degrading pathways first, using any replenishment only periodically, and she cautions that enthusiasm for NAD infusions and supplements has outpaced the evidence.

Key takeaways

• Ask why a marker is low before simply replacing it, Yurth urges
• Yurth presents CD38 and NNMT as the leak to address in NAD decline
• Consider downstream effects on methylation, not just the target level
• Treat continuous NAD boosting as unproven and potentially counterproductive, in Yurth’s view

Episode details: published July 5, 2025 · 7.3K views · 4:28 long. Summary written by Self Growth Videos from the episode itself. The longevity and peptide concepts described are Dr. Elizabeth Yurth’s, presented for education — not medical advice. Consult a qualified professional before changing your own health practices. Disclosure: Dr. Yurth is co-founder and Chief Medical Officer of the Boulder Longevity Institute, a clinic, and BLI Academy sells clinician education.

← Previous: What Are Peptides & How Are They Helpful? · Next: The Best Peptide for Longevity →

All Dr. Elizabeth Yurth videos · Dr. Elizabeth Yurth profile · Boulder Longevity Institute (official site)