When cellular energy production is impaired, no diet, supplement, or health protocol can work as intended. In this episode, Dr. Chris Masterjohn, nutrition scientist and expert in micronutrients and metabolism, explains why mitochondrial function is the limiting factor behind stalled progress, persistent fatigue, and supplements that stop working over time. He breaks down why vitamin D supplementation often creates new problems when it is taken without proper nutrient balance, how high doses can disrupt other systems in the body, and why sunlight has biological effects that vitamin D pills alone cannot replicate. Join the most comprehensive *female-specific community for health and longevity optimization.* After over a decade dedicated to human performance and women’s health, I created this space to share everything you need to know to optimize health and lifespan.