Looking for insights from U.S.-based endocrinologists, urologists, nutritionists, dietitians, or men’s health experts on the role of vitamins and minerals in supporting healthy testosterone levels in men—especially after age 40. Which nutrients are most important for natural testosterone production, and what does current research suggest about vitamin D, zinc, magnesium, selenium, boron, and B vitamins? How do nutrient deficiencies affect energy, mood, muscle strength, libido, and hormonal balance? Additionally, are food sources more effective than supplements, and what lifestyle habits best support healthy testosterone naturally?