Just as a little side note. This was many years before my body completely broke down, but they were warning signs. My first doctor was an endocrinologist that I went to when my energy levels and mood started unexplainably slipping. Two of the tests that came back low were testosterone and Vitamin D (down around 25 ng/mL). In hindsight it was due to nutrient deficiencies due to malabsorption, which in turn was due to exocrine pancreatic insufficiency (SIBO and Candida overgrowth issues also did not help).